USGS Global Visualization Viewer: Site
Description
The USGS Global Visualization Viewer
(GloVis) is a quick and easy online search and order tool for selected
satellite and aerial data. The viewer allows user-friendly access to
browse images from the multiple EROS data holdings. Through a graphic
map display, the user can select any area of interest and immediately view all
available browse images within the USGS inventory for the specified location.
From the browse image viewer page, the user may either navigate to view
adjacent scene locations or select a new area of interest. GloVis also offers
additional features such as cloud cover limits, date limits, user-specified map
layer displays, scene list maintenance, and access to metadata. An ordering
interface is provided for data that have processing options available.
A downloading interface is
provided for datasets that are available at no charge.
The GloVis website requires the use of JavaScript. If a warning appears
saying that JavaScript is turned off in your browser, please adjust your
browser's settings.
The Browse Image Viewer application is implemented as a Java applet. It
works with either the web browser's built in version of Java, or with the
Java plug-in available from Sun. Note that most of the features are only
available when using the Java plug-in from Sun (or a browser with an
equivalent built-in version of Java). These features also require the user
to answer "yes" to the security warning dialog that is displayed before the
Browse Image Viewer application is shown. Answering "yes" to the security
warning dialog grants the application the privileges required to access the
user's local hard drive. The application uses this to do things like save the
contents of the scene lists to the user's computer and reload them later
at the user's request. Answering "Always" is the same as answering "yes",
and will eliminate needing to answer the question on future visits to the
web site.
The viewer application has four basic components: the menu bar, the controls
on the left side of the main display, the browse images displayed on the right
side, and the status bar along the bottom of the viewer.
The Browse Image Viewer application uses separate threads of execution for
downloading data from the GloVis server. While data is being read from the
server, various indicators are displayed in the image area of the display. The
indicators describe what is being read, such as "Reading Inventory" to indicate
the list of available scenes is being read, "Loading Imagery" to indicate
browse images are being read, or "Loading Map Layers" to indicate map layers
are being loaded. While images are loading, a coverage map is drawn in light
blue to indicate where scenes are being loaded. The user can still interact
with the applet while data is being read from the server, although some
functions may be disabled temporarily.
Menu Bar
The Browse Image Viewer has a menu bar at the top
to provide an interface to many of the options available in the viewer. The
following paragraphs provide details on each of the available menu entries.
NOTE: On an Apple Macintosh, the menu bar selections are added to the menu
at the top of the display instead of directly to the Browse Image Viewer.
Collection Menu
The Collection menu allows the displayed dataset to be changed. The
menu is organized into a cascading menu for each of the different types
of dataset collections. The default dataset is set to the dataset selected
on the home page. For more information about each collection, see
About Browse Images.
NOTE: While the tool does allow the user to search multiple datasets,
the scene list for each dataset is maintained
separately. To order data from different datasets, you will need to
order each list separately. The only exception to this is the
Landsat 4 - Present scene list which shows the combined contents
of the Landsat 8 OLI (coming in 2013), Landsat 7 ETM+,
Landsat 7 ETM+ SLC-off, Landsat 4-5 TM, and Landsat 4-5 MSS scene lists.
Ordering the Landsat 4 - Present scene list will order the scenes from
all the related scene lists.
Resolution Menu
The Resolution menu allows the resolution displayed in the image display
area to be changed. All resolutions of browse images (and selected map
layers) are displayed in the Lambert Azimuthal Equal Area projection,
except for MODIS data which is displayed in the Sinusoidal projection and
NAPP/NHAP data which is displayed in the geographic projection. At the
highest resolution, a single scene is shown.
NALC Triplicates, Tri-Decadal TM, and Tri-Decadal 1-5 MSS
1000 meters in GIF format
480 meters in JPEG format
ETM+ Pan Mosaics
1000 meters in GIF format
285 meters in JPEG format
TM Mosaics
2000 meters in GIF format
700 meters in JPEG format
ASTER
1000 meters in GIF format
400 meters in GIF format
90 meters in JPEG format
MODIS
10000 meters in JPEG format
5000 meters in JPEG format
NAPP
Note that NAPP data is in the geographic projection, so pixel
sizes are in degrees.
low (0.00045 degrees) in JPEG format
high (0.00015 degrees) in JPEG format
NHAP
Note that NHAP data is in the geographic projection, so pixel
sizes are in degrees.
low (0.00090 degrees) in JPEG format
high (0.00030 degrees) in JPEG format
For band combinations and further details on the browse image, see
About Browse Images.
Map Layers Menu
The Map Layers menu allows the displayed map layers to be selected.
The map layers available include administration boundaries, the current
collection grid representation, country boundaries, a north arrow, a user
defined point of interest, protected area points, protected area polygons,
railroads, roads, an overlay of the scenes in the scene lists, water
(rivers and shorelines), and cities. The overlay of the scenes in
the scene lists is enabled by default.
NOTE: Due to reprojection issues, the map layers shown in the display
may be slightly inaccurate relative to the satellite browse image. The
map layer display should only be used as a general guide.
NOTE: Some map layers are not available for MODIS data.
The option to load shapefiles from the user's local computer is also
available if the applet was granted sufficient privileges by answering
"Yes" to the security warning when the applet loaded.
The options in the Map Layers menu include the following. Note that the
colors mentioned for the map layers are the default colors. In most
cases the colors can be modified using the Modify Colors Dialog.
All Map Layers: An overlay of all the map layers that are
available for the current dataset is added to the current browse image
display. Note: The example image does not include the north arrow.
Address Search Result: An icon indicating the last displayed
location from the Search for Address
option is shown in the image display area. The address search result
is shown as an yellow "stick-pin".
Admin boundaries: An overlay of administration boundaries is
added to the current browse image display. The administration
boundaries are white in color. The administration boundaries layer
includes country, state, and other large-scale cultural boundaries.
Cities: An overlay of major world cities is added to
the current browse image display. Both the city location and name are
yellow. Capital cities are indicated by a star icon and other cities
are indicated by a yellow dot. Smaller cities will be shown at higher
resolutions.
Collection Grid: An overlay of the WRS-2 or WRS-1 scene
centers (displayed as yellow squares), the MODIS grid tile outlines
(displayed as a yellow outline around the image), or the UTM grid
centers for the Mosaic datasets (displayed as yellow squares) are added
to the current browse image display.
Country boundaries: An overlay of country boundaries is
added to the current browse image display. The country boundaries are
white in color. The country boundaries layer is a subset of the admin
boundaries layer that includes only the country boundaries. Note that
the country boundaries are drawn using wider lines than the admin
boundaries.
North Arrow: An overlay of an arrow pointing north is added
to the upper left corner of the current browse image display. The arrow
is white in color with a black outline. The arrow rotates in the
direction of north when moving to different locations. This is
provided since the projection used to display the browse images
preserves pixel area while distorting direction.
Point Of Interest: An overlay of a users selected
point of interest is added to the current browse image display. The
point of interest feature resembles an orange "stick-pin".
Protected Area Points: An overlay of protected areas is
added to the current browse image display. The protected areas are
displayed as yellow dots. When the mouse cursor is over a point, the
name of the protected area is displayed in the applet status bar after
the lat/long display. The Protected Area Polygons and Points datasets
sometimes contain different areas.
NOTE: The protected area information displayed by GloVis was obtained
from the
World Database of Protected Areas (WDPA) Consortium, December
2007 version. The World Database on Protected Areas (WDPA) is
a joint venture of UNEP and the IUCN, produced by UNEP-World
Conservation Monitoring Centre (UNEP-WCMC) and the IUCN WCPA
working with governments and collaborating NGOs. The WDPA is
updated continuously providing the most current data on
protected areas worldwide. Please go to
http://www.unep-wcmc.org/protected-areas_24.html
for more information. UNEP-WCMC bears no responsibility for
the integrity or accuracy of the data contained herein.
GloVis processes the original data to the projection being
displayed and reformats it into files that are easier to use with the
applet.
Protected Area Polygons: An overlay of protected areas is
added to the current browse image display. The protected areas are
displayed as polygons and are displayed in yellow. When the mouse
cursor is over a polygon, the name of the protected area is displayed
in the applet status bar after the lat/long display.
NOTE: The protected area information displayed by GloVis is obtained
from the
World Database of Protected Areas (WDPA) Consortium, December
2007 version. The World Database on Protected Areas (WDPA) is
a joint venture of UNEP and the IUCN, produced by UNEP-World
Conservation Monitoring Centre (UNEP-WCMC) and the IUCN WCPA
working with governments and collaborating NGOs. The WDPA is
updated continuously providing the most current data on
protected areas worldwide. Please go to
http://www.unep-wcmc.org/protected-areas_24.html
for more information. UNEP-WCMC bears no responsibility for
the integrity or accuracy of the data contained herein.
GloVis processes the original data to the projection being
displayed and reformats it into files that are easier to use with the
applet.
Railroads: An overlay of major railroads is added
to the current browse image display. The railroads are dark pink in
color.
Roads: An overlay of major roads and thoroughfares is added
to the current browse image display. The roads are tan in color.
Scene List Overlay: An overlay of the scenes added to any
of the scenes lists in the applet is added to the current browse image
display. The scene list overlay is shown in green. The scene lists
to include can be modified using the Configure Scene List Overlay Dialog box.
Water: An overlay of major rivers and shorelines is added
to the current browse image display. The water features are blue in
color.
No Map Layers: All previously selected map layers will be
removed from the current browse image display.
Modify Colors...: Opens a dialog
box that allows the color used to display each of the standard map
layers to be modified. To change a color for a map layer, click on the
button associated with the map layer and select the color to use. The
color change is not applied until the dialog's Ok or Apply buttons are
pressed. The Default button returns all the map layers to their
original colors (the Ok or Apply buttons need to be pressed to apply
the change). The Cancel button will exit the dialog without applying
any unapplied changes.
Search for Address...: Opens
the Search for Address Dialog Box which provides the ability to search
for an address and display the location of the address in the image
display area.
The Search for Address Dialog Box provides the following:
Enter Address: The enter address text field allows
entering an address. Pressing the enter key initiates the search.
The address can be a city name, street address, zip code, or even a
major landmark.
Address Search Results: After a search completes, the
results are displayed in a list. The results provide the full
matching address along with the latitude and longitude of the
address. Double-clicking on one of the results displays the
location in the image display area and marks it with an icon (only
the last address selected is displayed).
Search: The search button initiates a search for the
address in the enter address text field, just like pressing the
enter key does in the enter address text field.
Display: The display button displays the currently
selected result in the results list, just like double-clicking on
the address in the list.
Clear: The clear button clears the address entry field
and search results list.
Close: The close button closes the dialog box.
Set Point Of Interest...: Opens the Point Of Interest Dialog
Box which provides the ability to display a point in the image display
area by entering a latitude and longitude.
The Point of Interest Dialog Box has the following characteristics:
Latitude: The latitude entry box for entering a valid
Latitude.
Longitude: The longitude entry box for entering a
valid Longitude.
Set: The set button sets the Point of Interest
Clear:The clear button removes the previously set
Point of Interest.
Close:The close button closes the dialog box.
Configure Scene List Overlay...:
Opens a dialog box that allows selecting which scene lists
should be shown as part of the Scene List Overlay map layer. A
checkbox for each dataset is provided. Buttons to set or clear all
the checkboxes are provided. Any changes are applied by the Ok and
Apply buttons, while the Cancel button will exit without applying
any unapplied changes.
Read Shapefile...: Displays a file open dialog box to allow
choosing a shapefile to read. When a shapefile is chosen, the user
is also allowed to choose the color used for displaying the shapes.
Note that only shapefiles using geographic coordinates are supported
and the shapefile should be referenced to the WGS84 or NAD83 datum
for best results. When the shapefile is loaded, the image display
area is centered at the center of the shapefile coverage if it is
not already displaying an area covered the shapefile.
Show Shapefile Attributes...: Opens a dialog box that
displays the attributes for the last shapefile shape that has been
clicked on. Each shapefile that is loaded also has a tab available
in the dialog box that allows configuring the following:
The attributes to display when a shape from the file is
clicked on.
The color to use when drawing the shapes from the file.
The attribute to display in the statusbar when the mouse
is hovering over a shape from the file.
A simple interface that allows displaying a subset of the
shapes in the file by choosing to display only the shapes that
have a particular value for an attribute.
Shapefiles: For each shapefile that is read, a menu option
with a checkbox is added to the menu to allow turning the display of
that shapefile on and off. When the shapefile display is turned on,
the image display area is centered at the center of the shapefile
coverage if it is not already displaying an area covered the shapefile.
Tools Menu
The Tools menu provides the following options:
Default to Selected Date: When selected, changing the
displayed active scene to a different date will change all the
displayed scenes to the closest available date.
NDVI Graph...: Opens the
NDVI Graph Dialog Box for Landsat, EO1, MRLC, Tri-Decadal TM,
Tri-Decadal ETM+ and Tri-Decadal Pansharp ETM+ only.
Print...: Allows printing the current contents of the main
Browse Image Viewer display. It opens a dialog that allows setting
printing parameters and selecting the destination printer. The
dialog displayed is specific to the operating system being used.
Refresh: Refreshes the data displayed by reloading the
scene inventory and browse images from the web server. This is
useful to users who are waiting for the most recently acquired
scenes to become available. This can also be done by using the
"CTRL+R" keyboard shortcut on most browsers.
The File menu provides options to save files to the user's hard drive
and load data into the GloVis application from the user's hard drive.
The File menu is only available when using the Java plug-in and the GloVis
applet was granted sufficient privileges by the user answering "yes" to the
security warning dialog that is displayed before the applet loads.
Save All Scene Lists...: Saves the contents of all the
dataset scene lists. See Save and
Load Scene Lists.
Save Hidden Scene Lists...: Saves the contents of all the
hidden scene lists. See Save and
Load Scene Lists.
Load Hidden Scene List...: Loads a previously saved hidden
scene lists file. See Save and Load
Scene Lists.
Download Visible Browse & Metadata...: Downloads the
original browse image and metadata file for the scenes visible on
the display. See Download Visible
Browse & Metadata.
Download Path path, Row row Browse &
Metadata...: Downloads the original browse image and metadata
file for the scenes in path path and row row that
match the current search limits. See
Download Browse & Metadata.
Download Scene List Browse & Metadata...: Downloads the
original browse image and metadata file for the scenes in the
current scene list. See
Download Scene List Browse & Metadata.
Help Menu
The Help menu provides selections for several different sources for help.
The menu selections include:
About GloVis:Pops up a box identifying the GloVis release.
Product Information: Provides a link to a web page with
additional information about the currently selected dataset.
Data Acquisition Schedule: Provides a link to the
acquisition schedule for the currently selected dataset. Note:
Some datasets do not have an acquisition schedule web page
available.
Data Acquisition Request: Provides a link to a web page that
allows submitting a request for a data acquisition. This is only
available for the EO-1 datasets.
Navigation Controls
The left side of the Browse Image Viewer has various naviation controls
that are explained in the following paragraphs.
Locator Map
The locator map is the map of the world in the upper left corner of the
Browse Image Viewer. It indicates the currently displayed location with a
small diamond-shaped icon. A new display location can be selected by
clicking on a location within the locator map. Scroll bars along the
right and bottom edges of the locator map allow navigation to areas not
currently in the viewing area. When the cursor passes over the locator
map, the status bar of the Browse Image Viewer displays the latitude and
longitude of the location under the cursor. The WRS path and row are
also displayed (except for MODIS data where the H/V tile numbers are
displayed, and the ETM+/TM mosaics where no path and row info is
displayed).
There are three different images displayed for the locator map. The
image used for most of the datasets is in the geographic projection.
For the MODIS datasets, a locator map in the sinusoidal projection is
displayed for the locator map. Clicking in the gray area that is off the
edge of the world will not change the displayed area in the image display
area.
For the NAPP and NHAP datasets, a geographic projection map of only the
lower 48 states is shown since the data is only available there.
WRS Path/Row or Horizontal/Vertical Tiles
For most datasets, the first and second fields display the second
version of the World Reference System (WRS-2) path and row (or WRS-1 for
Landsat 1-3 MSS data) of the active (highlighted) scene within the display.
For the MODIS datasets, the first and second fields display the
horizontal and veritical tile number of the MODIS reference grid. The
image display area can be moved to a new location by entering a new
path/row (or tile number) and pressing the enter key or clicking the "Go"
button. MODIS Tile numbers that fall outside the edges of the world are
rejected.
For the ETM+ Mosaic, TM Mosaic, and NHAP datasets, this field is not
available since there is no regular grid available.
For the NAPP dataset, the entry fields are the flight line and station.
Lat/Long
The first and second fields display the latitude and longitude of the
center of the active (highlighted) scene within the display. The browser
may be updated to a new location by entering new latitude and longitude
coordinates and pressing the enter key or clicking the associated "Go"
button.
Max Cloud
The cloud cover dropdown list allows the user to restrict the displayed
browse images to only those that meet specific cloud cover restrictions. By
default, the USGS Global Visualization tool will display all browse images
in the archive (Max Cloud 100%). A maximum cloud restriction of 0% (Max
Cloud 0%) will display only cloud-free images. The cloud cover restriction
can be set in 10% increments.
Note: The cloud cover values for each scene are provided to GloVis
by the data provider. They are typically estimates and may not accurately
reflect the cloud cover actually present in the scene.
Note: The Max Cloud cover option is not available for some datasets.
Arrow Buttons
The arrow buttons allow spatial navigation from the selected scene to
the next adjacent path and row (or tile). The up/down arrows will update
the browse display to be centered over the next or previous row. The
left/right arrows will update the browse display to be centered over the
next or previous path (or horizontal tile).
When displaying ASTER data at the 400m resolution, the arrow buttons will
step by 1/3 of a path or row.
Scene Information
The information displayed pertains to the active (highlighted) scene
within the display and varies with the selected dataset. It can include:
ID: the scene ID
Cloud Cover: the estimated cloud cover
Quality: image quality value ranging from 0-9
Date: the acquisition date
Pointing Status: for EO-1 data, an indication is provided
on where the sensor was pointing (at nadir, within the path/row,
or outside the path/row)
Sensor: for the Landsat 4 - Present data, an indication is
provided for the source sensor
Roll: film roll number (for NAPP/NHAP data only)
Frame: frame number on the roll of film (for NAPP/NHAP data
only)
Proj: project name that collected the scene (for NAPP/NHAP
data only)
The information in the scene information area can be copied to the
clipboard for pasting to other applications. The method to copy
information to the clipboard varies depending on the browser and Operating
System used. For most browsers, highlight the information
to copy using the mouse and copy it by pressing "CTRL-C". For some
browsers, the technique is to highlight the information to copy using the
mouse, click the right mouse button, and select "copy". Some browsers
may require other methods to be used.
Date Selection
This area allows the user to navigate through all available acquisition
dates, which also meet any user-specified Search Limits. Note that the dates available
in the month and year dropdown lists reflect the year and month ranges set
in the Search Limits. For Landsat and MODIS data, the date navigation
applies to the currently selected path/row or tile. For ASTER and EO-1
data, the date navigation applies to all the currently displayed scenes or
scenes that cross the User Defined Area.
Note that this field may not be present for some datasets.
Landsat and MODIS Date Navigation
The date navigation applies to the active (highlighted) path and
row or horizontal and vertical tile.
Go: will display the user-specified month and year
Prev Scene: will display the previous acquisition date
Next Scene: will display the next acquisition date
ASTER and EO-1 Date Navigation
The date navigation applies to all currently visible scenes or
to scenes that intersect the User
Defined Area. Since ASTER and EO-1 data are not aligned to
WRS path and rows, scene navigation is based on satellite
swaths.
Go: will make the first displayed scene matching the
user-specified month and year the active scene
Prev Scene: will make the previous scene in the current
swath the active scene or if at the beginning of a swath it
moves to the end of the previous swath
Next Scene: will make the next scene in the current
swath the active scene or if at the end of a swath it moves to
the start of the next swath
Double left-clicking on a scene in the browse image display will perform
the same function as selecting the "Next Scene" button (The first click
will select the scene below the cursor, making this not very useful for
ASTER data).
NOTE: A date selection button will be disabled if the active scene is the
first or last available scene and no previous or next scene exists in the
inventory (according to any user-specified limits set in the Search Limits Dialog Box).
Scene List
The scene list allows the user to maintain a list of selected scenes for
each dataset. The list includes the scene ID for each scene selected. The
user can add scenes to or delete scenes from each list or send the contents
of the list to the USGS Shopping Cart to access further options for
downloading scenes or requesting additional processing.
The vertical scroll bar along the right margin of the list allows the user
to navigate up and down within the list. The tooltip shown when the mouse
cursor hovers over the scene list indicates how many scenes are in the list.
Note: There is a maximum URL length that limits the number of
scenes that can be passed to a shopping cart. If this limit is reached,
pressing the order or submit button only submits as many scenes to
the shopping
cart as the URL limit allows and a message box is displayed warning the
user this has happened. The rest can be added by pressing the order
or submit button again (as many times as it takes).
Add: The currently active (highlighted) scene within the
browse viewer display is added to the scene list.
Delete: The selected scene within the scene list is deleted
from the list. A scene is selected by clicking on the scene ID with
the mouse.
Send to Cart: Places all scenes within
the current scene list for
the selected dataset only, up to the limit imposed by
the maximum URL length, into the user's Shopping Cart.
Right-clicking: Right-clicking on the scene list displays a
popup menu for the selected scene in the list. The menu allows the
following actions:
Scene Information: A summary of selected scene ID, cloud
cover (when available), and acquisition date. A quality value
will be included for Landsat data only.
NOTE: selecting the scene information in the menu does not
result in any action being taken.
Show Metadata: A detailed set of metadata is displayed
in a new browser window. FGDC metadata is available via a link
at the bottom of the metadata display for the Landsat and EO-1
datasets.
Show Browse: The original full-resolution browse image
is displayed in a new browser window.
Display: The scene is displayed as the active
(highlighted) scene in the image area display. The viewing
location is repositioned if needed.
NOTE: The display option will be disabled if the selected
scene in the list does not meet the current search limits.
NOTE: double-clicking with the left mouse button on a
scene in the scene list will also display the scene.
Delete: The scene is deleted from the list.
Send to Cart: Places all scenes within
the current scene list for
the selected dataset only, up to the limit imposed by
the maximum URL length, into the user's Shopping Cart.
Clear List: Removes all scenes from
the current scene list for
the selected dataset only.
Restore: Restores the list of scenes to the Scene List
after placing an order or clearing the list.
This is helpful when an order failed to be entered.
(This option must be used immediately
after placing an order. Once another scene is added to the
scene list, the restore list is gone and the restore option
will be unavailable.)
NOTE: All
datasets are entered into the USGS shopping cart.
NOTE: On an Apple Macintosh, right-clicking is performed by holding
down the option button and clicking on the single mouse button.
IMPORTANT: The USGS Global Visualization Viewer will maintain a
separate scene list for each dataset (except for the Landsat 4 - Present
dataset which combines the scene lists for all the related datasets).
Multiple
datasets may be alternately searched and multiple lists may be created.
However, each scene list must be individually ordered. After a
scene list has been ordered, that scene list will be emptied of all
previous contents.
Note: All Aerial, Landsat, EO-1, ASTER L1B and MODIS datasets are entered
into the USGS shopping cart.
When ordering multiple scene lists,
the scenes ordered will be combined to populate a
single order in the Shopping Cart.
Image Display Area
The right side of the Browse Image Viewer displays browse images and map
layers for the currently selected dataset and viewing area. The following
paragraphs provide some details on the image display area.
Keyboard Interface
If the mouse cursor is clicked in the browse image area, a keyboard
interface is available for selecting scenes. The following keys are
available:
Arrow Keys: The keyboard arrow keys will move the center of
the display a single path or row (or tile) in the direction of the
arrow pressed (or 1/3 of a path or row for ASTER data at 400m),
just like the arrow buttons.
Page Up: The page up key will display the previous
acquisition date, just like the "Prev
Scene" button.
Page Down: The page down key will display the next
acquisition date, just like the "Next
Scene" button.
Home: The home key will display the first available
acquisition date.
End: The end key will display the last available acquisition
date.
NOTE: As with the display buttons, the keyboard interface will be
limited to any user-specified search limits.
Mouse Interface
The mouse buttons have the following functions in the browse image area
(except when the User Defined Area dialog box is open. For the mouse
interface in this case, see the User Defined
Area documentation.)
Left-clicking: Left-clicking on a scene makes that scene the
active scene and places it on top of any other images on the
display.
Left-click, hold + drag: Pressing and holding the left mouse
button in the browse image area and dragging the mouse will adjust
the area being displayed. Releasing the mouse button will
automatically load the scenes to display for that area. This can be
used to navigate without using the arrow buttons. It is also
useful when viewing areas with scrollbars (like Landsat 7 ETM+ at
240 meters sometimes shows). If being used to navigate to new
areas, it may be helpful to turn on the political boundary map
layer.
Double Left-clicking: Double left-clicking on a scene
updates the scene to the next acquisition date like the Next Scene button and displays the scene
selected (highlighted) in the image display area.
NOTE: This option only allows the image to move to the next
available scene and not back to the previous scene.
Alt/Shift/CTRL Left-clicking: Holding down the Alt, Shift,
or CTRL key (depending on the operating system) when left-clicking
on a scene moves that scene behind all the other visible scenes.
If the scene was the active scene, the new top scene is made the
active scene.
Right-clicking: Right-clicking on a scene in the browse
image area will display a pop-up menu for the scene. The menu
displays the following:
Scene Information: Summary of selected scene ID, cloud
cover, and acquisition date. Quality value will be included
for Landsat data only.
NOTE: No action occurs when scene information is selected.
Show Metadata: A detailed set of metadata for the scene
is displayed in a new browser window. FGDC metadata is
available via a link at the bottom of the metadata display for
the Landsat and EO-1 datasets.
Show Browse: The original full-resolution browse image
for the scene on is displayed in a new browser window.
Add to Scene List: The scene on is added to the scene
list.
Add All to Scene List: All currently visible scenes are
added to the scene list.
NOTE: This option is not available for ASTER or EO-1 data.
Add User Area Scenes: All scenes currently in the
user-defined area will be added to the scene list.
Note: This option is only available when the User-defined
Area is enabled.
Remove From Scene List: The scene is removed from the
scene list. This option will be disabled if the scene is not
in the scene list.
Hide Scene: The scene is added to the
hidden scene list and the
scene is removed from the image display area.
Bring to Front: The scene is placed in front
of all other scenes in the area.
Send to Back: The scene is placed behind all
other scenes in the area.
Previous Avail. Date: The scene is changed
to the previous available date. This option will be disabled if
there are no previous scenes available.
NOTE: This option is not available for ASTER or EO-1 data.
Next Avail. Date: The scene is changed to
the next available date. This option will be disabled if there
are no scenes after the displayed scene.
NOTE: This option is not available for ASTER or EO-1 data.
Set Point Of Interest: Sets a point of interest where
the cursor is on the display, enabling the point of interest
map layer. The point selected latitude and longitude values are
added to the Point of Interest dialog box.
Set Scenes To Date: The Date
shown in the menu is the acquisition date of the scene selected.
All the displayed scenes are set to the acquisition date
that is nearest to the shown Date (subject to any
search limits that are currently applied). This provides a
quick way to set all the displayed scenes to roughly the same
date.
Note: This option is not available for ASTER or EO-1 data.
Default Scene: The scene is changed to the default scene
NOTE: For ASTER and EO-1 data, if the point clicked on intersects
multiple scenes the right-click menu has a submenu on it to select between
the scenes. The selected one is made the active scene.
NOTE: On an Apple Macintosh, right-clicking is performed by holding
down the option button and clicking on the single mouse button.
Latitude and Longitude Display
When the cursor is over the browse image display or the locator map, the
status bar of the browser displays the latitude and longitude under the
cursor. The values are reported as decimal degrees.
Cooperator Logo
For each data set, a logo for the cooperator who made the data available
is displayed in the lower left or lower right corner of the browse image
area. Clicking on the logo will open a new browser window to the
cooperator's web site.
Status Bar
The bottom of the Browse Image Viewer displays a status
bar for the application. The status bar is separated into three areas. Those
three areas provide the following information (from left to right):
The resolution being displayed
The search limits in effect (date, scene list, quality, user defined
area, and/or data version)
The latitude and longitude of the location under the mouse cursor, and
WRS path and row (or tile number, or flight line and station) if the
mouse cursor is over the locator map. If a protected areas map layer
is displayed and the mouse cursor is over an area, the protected area
name is displayed. If a user shapefile is displayed, information may
be displayed for the shape the mouse cursor is over.
Tools Menu Options
The Browse Image Viewer provides several tools under the Tools Menu that allow interacting with the application.
Most of the options open a dialog box. The options are described in the
following paragraphs.
Hidden Scene List
The Hidden Scene List dialog box provides the capability of hiding and
unhiding scenes in the image display area. This functionality is useful
if a user wants to only view certain images in the display. The user
can then pick what scenes they want hidden or unhidden. The tooltip shown
when the mouse cursor hovers over the scene list indicates how many scenes
are in the list.
The Hidden Scene List dialog has the following characteristics:
Scene List Name: The name of the current hidden scene list
appears at the top of the dialog box.
Scene List: The list includes the scene ID, cloud cover
percentage, and acquisition date for each scene in the list.
A quality value will also be included for Landsat data. The
vertical scroll bar along the right margin of the list allows the
user to navigate up and down within the list.
Hide Button: The currently active (highlighted) scene within
the Image display area is added to the hidden scene list and the
image is removed from the image display area.
Unhide Button: The selected scene within the hidden scene
list is deleted from the list and the image is added to the image
display area.
Close Button: Pressing the close button closes the dialog
box.
NDVI Graph Dialog Box
The NDVI Graph dialog box provides the capability of displaying
a line graph of the Normalized Difference Vegetation Index (NDVI) data for
the selected scene's WRS-2 path and row.
Line Graph tab:
Line Graph: The line graph displays the NDVI values for
two-week periods for the year of the currently-selected scene. A
vertical black line indicates the date of the selected scene.
Dates for the the end of each two-week period are indicated
across the top by the day of year (also called Julian day) and
across the bottom by month and day.
Clicking graph area: Clicking in the graph area will
select the scene closest to the date clicked on.
Print Button: Pressing the print button allows the
current contents of the line graph to be sent to a printer. A
dialog opens that allows setting the printing parameters and
selecting the printer to use.
Close Button: Pressing the close button closes the
dialog box.
Select Landcover:
Landcover Checkboxes: Allows the user to turn the
landcovers on and off. These checkboxes affect the Line Graph tab.
Set Default Button: Selects the top five landcovers
for the selected WRS-2 path and row in the display area.
Close Button: Pressing the close button closes the
dialog box.
FAQ:
The Frequently Asked Questions (FAQ) tab answers some
common questions about NDVI data.
Scene List
The Scene List dialog box provides an expanded version of the scene list on the left side of the Browse Image
Viewer. The two scene lists contain the exact same list of scenes. The
primary differences are that the list displays more information about each
of the scenes in the list and there are more buttons available for
interacting with the list (essentially duplicating the right-click menu
available in the scene list on the left side of the viewer).
The tooltip shown when the mouse cursor hovers over the scene list
indicates how many scenes are in the list.
Note: There is a maximum URL length that limits the number of
scenes that can be passed to a shopping cart. If this limit is reached,
pressing the order button only submits as many scenes to the shopping
cart as the URL limit allows and a message box is displayed warning the
user this has happened. The rest can be added by pressing the order button
again (as many times as it takes).
The following are available in the Scene List dialog box:
Scene List Name: The name of the current scene list appears
at the top of the dialog box.
Scene List: The list includes the scene ID, cloud cover
percentage, and acquisition date for each scene in the list.
A quality value will also be included for Landsat data. The
vertical scroll bar along the right margin of the list allows the
user to navigate up and down within the list.
Add: The currently active (highlighted) scene within the
image area display is added to the scene list.
Delete: The selected scene within the scene list is deleted
from the list.
Clear List: All scenes in the current scene list are removed
from the list.
Display: The scene selected within the scene list is
displayed as the active (highlighted) scene in the image area
display. The viewing location will be repositioned if needed.
NOTE: The display option will be disabled if the selected scene
in the list does not meet the current search limits.
NOTE: double-clicking with the left mouse button on a
scene in the scene list will also display the scene.
Send to Cart: Places all scenes within
the current scene list for
the selected dataset only, up to the limit imposed by the
maximum URL length, into the user's Shopping Cart.
Show Metadata: A detailed set of metadata for the scene
selected within the scene list is displayed in a new browser
window. FGDC metadata is available via a link at the bottom of the
metadata display for the Landsat and EO-1 datasets.
Show Browse: The original full-resolution browse image for
the scene selected within the scene list is displayed in a new
browser window.
ASTER
90 meter sub-sampled JPEG in a rotated UTM
projection
240 meter sub-sampled JPEG in satellite (path)
orientation
EO-1 Hyperion
120 meter sub-sampled JPEG in satellite (path)
orientation
Landsat 4-5 TM, Landsat 4-5 MSS
480 meter or 240 meter sub-sampled JPEG in satellite
(path) orientation
Landsat 1-3 MSS
480 meter or 240 meter sub-sampled JPEG in satellite
(path) orientation for most dates, but in a north-up
orientation for January 1979 - May 1981
MODIS
5000 meter sub-sampled JPEG in the sinusoidal projection
NALC
480 meter sub-sampled JPEG in satellite (path)
orientation
NAPP
Sub-sampled 5.5 x 5.5 mile area JPEG
B&W NHAP
Sub-sampled 11 x 11 mile area JPEG
CIR NHAP
Sub-sampled 8 x 8 mile area JPEG
Tri-Decadal TM, and Tri-Decadal 1-5 MSS
approximately 450 meter sub-sampled JPEG in a UTM
projection
Tri-Decadal ETM+ Mosaics
approximately 285 meter sub-sampled JPEG in a UTM
projection
Tri-Decadal TM Mosaics
approximately 650 meter sub-sampled JPEG in a UTM
projection
For band combinations and further details on the browse image,
see About Browse Images.
Restore: Restores the list of scenes to the Scene List
after placing an order or clearing the list. This is helpful when
an order failed to be entered. (This option must be used immediately
after placing an order. Once another scene is added to the scene
list, the restore list is gone and the restore option will be
unavailable.)
NOTE: All datasets
are entered into the USGS shopping cart.
Close: Closes the dialog box.
Right-clicking: Right-clicking on the scene list displays a
popup menu for the selected scene in the list. The menu is
identical to the menu described for the scene
list on the left side of the Browse Image Viewer, with the
exception that the "More..." option is not shown.
Search For Scene
The Search for Scene dialog box provides the capability to search for
a specific scene using a known scene ID. This functionality is useful if
a user wants to locate a specific scene quickly. This is especially useful
for ASTER granules since the granule ID does not contain any information
to identify the location or acquisition date of the granule.
The Search for Scene dialog has the following characteristics:
Scene ID hint: The top of the dialog provides a hint for
entering the scene ID for the current dataset. For example, for
many Landsat datasets, a 16 digit scene ID should be entered.
For an ASTER granule, the last 10 digits of the granule ID should
be entered (i.e. if the granule ID is "AST_L1A.003:2012758270",
enter the ten digits after the ":") For a MODIS granule, a 45
digit ID should be entered but a search can also be entered with
part of the ID that includes the horizontal and vertical tile and
some of the ID before and after the tile numbers.(i.e. if the
granule ID is "MYD09A1.A2003001.h16v06.004.2004087194457.hdf",
entering "A2003001.h16v06.004").
Scene ID entry area: Below the scene ID hint is a text entry
field to allow the scene ID to be entered. Most browsers and
Operating Systems allow pasting text into this area.
Search status area: Below the scene ID entry area, an area
is reserved for displaying the status of the current search, or the
results from the last search.
Search Button: Pressing the search button initiates a search
for the scene ID currently in the scene ID entry area. If a
matching scene is found, the scene is displayed in the image
display area.
Close Button: Pressing the close button closes the dialog
box.
Search Limits
The Search Limits dialog box provides the capability to limit the
displayed scenes by various metadata fields. Note that the search limits
options can vary for each dataset. The limits are applied immediately
after being accepted and are applied when navigating to new dates. The
following are available in the Search Limits dialog box:
Start Year: The Start Year dropdown list allows the user to
limit the earliest year for displaying scenes.
End Year: The End Year dropdown list allows the user to
limit the latest year for displaying scenes.
Start Month: The Start Month dropdown list allows the user
to limit the earliest month for displaying scenes.
End Month: The End Month dropdown list allows the user to
limit the latest month for displaying scenes.
Max Cloud: The cloud cover dropdown list allows the user to
restrict the displayed scenes to only those that meet specific
cloud cover restrictions. By default, the USGS Global Visualization
tool will display all browse images in the archive (Max Cloud
100%). A maximum cloud restriction of 0% (Max Cloud 0%) will
display only cloud-free images. The cloud cover restriction can be
set in 10% increments.
NOTE: The cloud cover values for each scene are provided to
GloVis by the data provider. They are typically estimates and may
not accurately reflect the cloud cover actually present in the
scene. The maximum cloud cover limit will not be available for
datasets that do not provide cloud cover values. Not all datasets
provide cloud cover values.
Start Path: The Start Path dropdown list allows the user to
limit the first path for displaying scenes.
End Path: The End Path dropdown list allows the user to
limit the last path for displaying scenes.
Start Row: The Start Row dropdown list allows the user
to limit the first row for displaying scenes.
End Row: The End Row dropdown list allows the user to
limit the last row for displaying scenes.
NOTE: Limiting search by path and row values is only available
for the Aster Sensor.
Min Quality: The quality value dropdown list allows the user
to restrict the displayed scenes to only those that meet the
selected quality value restrictions, ranging from 0 (lowest) to 9
(highest). By default, the USGS Global Visualization tool will
display all browse images in the archive (Min Quality 0). A
maximum quality value restriction of 9 (Min Quality 9) will display
only the highest quality images. The minimum quality is only
available for Landsat datasets.
Data Version: The MODIS data is periodically reprocessed and
new data versions created. The data version dropdown list allows
the user to restrict the data version displayed to a single data
version if desired, or data from all versions can be displayed.
The default is set to display all data versions.
Show only scenes in the scene list: The Show Scenes From
Scene List Only checkbox allows the user to limit the scenes
displayed to those that are currently in the scene list. See the Scene List, Scene List Dialog Box, and Mouse Interface for information on navigating the scene list.
Show only scenes in user defined area: The Show Only
Scenes In User Defined Area checkbox allows the user to limit the
ASTER and EO-1 scenes displayed to those that intersect the
user-defined area. This option is only available for ASTER and EO-1
datasets.
NOTE: If the user-defined area has not already been determined,
the User Defined Area dialog box will pop-up to allow the user to
define their area of interest. See the User Defined Area for more information.
Ok: The Ok button sets the search limits to the
selected limits and closes the dialog box. When viewing Landsat
data, any displayed scenes that violate the search limits will be
replaced with the scene with the closest date that meets the limits
(or simply removed if no scenes meet the limits). For ASTER and
EO-1 data, scenes that violate the limits will not be displayed or
loaded from the server.
Clear: The Clear button removes any previously set limits.
Apply: Same as Ok button, but doesn't close the dialog box.
Cancel: The Cancel button cancels any changes to the limits
and closes the dialog box.
Example: To limit the displayed scenes to June, July, and August
in the years 2000 and 2001 with 40% or less cloud cover and a quality value
of 9, set the following:
Click on the Start Year drop down box and select 2000.
Click on the End Year drop down box and select 2001.
Click on the Start Month drop down box and select
June.
Click on the End Month drop down box and select
August.
Click on the Cloud Cover drop down box and select 40%.
Click on the Min Quality drop down box and select 9.
(Landsat data only.)
Click on the Apply button.
The scenes that are displayed have the above limits applied.
NOTE: If a date range search limit is used, that search limit
remains in effect when a new dataset is selected. If the newly selected
dataset does not have any scenes in that date range, no scenes will be
displayed. For Landsat data, the quality value limit will remain in effect
when searching other Landsat products.
Swath Mode
The Swath Mode option appears on the Tools Menu for the ASTER and
Landsat datasets. A swath consists of images acquired on the same day,
along the same path, in consecutive rows. The default is for swath mode to
be off. Selecting the menu item will toggle the mode on and off. A check
appears next to the Swath Mode menu item when swath mode is on.
When swath mode is on, the browse images displayed are organized in
swaths and the navigation control behavior changes to function on swaths
instead of single scenes when it makes sense. The swath mode functionality
differs in the following ways:
A green border will highlight the scenes in the selected swath.
When swath mode is first entered, the displayed scenes are updated
to display swaths.
For Landsat datasets, navigating by date will change all the scenes
in the selected swath to the same date, if available.
For ASTER datasets, navigating by date will work similar to
non-swath mode, except that when a scene from a new swath is
selected, the whole swath is displayed on top of the other scenes
and highlighted with the swath highlight.
Options are added to the image display area right-click menu to
allow adding the scenes from a swath to the scene list or hide all
the scenes from the swath.
User Defined Area
The User Defined Area dialog box provides the capability to limit a
number of features for ASTER and EO-1 datasets to a specific region. This
functionality is useful for users who are interested in a specific search
area and want to avoid scanning through the many scenes that may be
displayed.
To build the user-defined area, open the dialog box. At this point, the
normal mouse interface is disabled and the following features come into
effect:
Mouse Features:
Add Points: Clicking a location on the image will add a
point. As a user continues to click on the image, points are added
and a polygon begins to form. Before a point can be successfully
added, it is checked to see if it causes an intersection with a
previously created line. Intersections make invalid polygons;
therefore, invalid points are not allowed.
Move Points: Clicking and dragging a point will move it to
the new location. Just as with adding points, moving a point that
causes intersections will not be allowed.
Buttons Available:
Close and Apply Area: When selected, this feature closes the
user-defined area and most functions will then be limited to that
area.
NOTE: This checkbox may be automatically selected if the
user-defined area is manually closed by adding or moving points.
Exit: Exits out of the User Defined Area dialog box. If the
Close and Apply Area checkbox is set, the polygon will remain
visible. Otherwise, it will be hidden.
Clear: Removes all points and lines.
Undo: Returns the user-defined area to the previous state
before the most recent action.
NOTE: After a clear, the undo memory is cleared after a new
point is added.
Goto: Moves the image area display back to the
user-defined area if the user has moved to a different location.
After the user-defined area has been completed and the Close and Apply
Area checkbox has been checked, exit the dialog box. Date Selection features will only apply to scenes
located within this area.
NOTE: To restrict all functions to the user-defined area, check the
Show Only Scenes In User Defined Area box in the Search Limit Dialog Box.
File Menu Options
The Browse Image Viewer provides several tools on the File Menu for interacting with the application. The
details of these options are described in the following paragraphs. Note that
these options are only available when using the Java plug-in and the GloVis
applet was granted sufficient privileges by the user answering "yes" to the
security warning dialog that is displayed before the applet loads. If both of
these conditions are not fulfilled, the File menu will not be available.
Save and Load Scene Lists
The user can save and load the contents of both the ordering scene lists
and the hidden scene lists.
When the user selects one of the save options, a dialog box is displayed
that allows the user to select the folder for storing the scene list file
and the file name. The user may enter the required information and press
the "Save" button, or cancel by pressing the "Cancel" button. After
pressing the save button, the application writes the contents of all the
scene lists (the ordering scene lists if the "Save All Scene Lists" option
was chosen, or the hidden scene lists if the "Save Hidden Scene Lists"
option was chosen) to the selected file.
When the user selects on of the load options, a dialog box is displayed
that allows the user to select a previously saved scene list file for
loading into the GloVis application. After selecting a file, the user can
press the "Open" button, or cancel by pressing the "Cancel" button. After
pressing the "Open" button, the application reads the selected file,
verifies that it contains valid scenes, and loads the scenes into the
ordering scene lists or hidden scene lists, depending on the option
selected.
File Format: The scene list file that is saved on the user's
computer is a simple text file. The file can be viewed in any application
capable of reading a text file. Also, the user can edit the contents of
the file to add or remove scenes if desired. Note: if the file is edited,
the format must be preserved to be able to be read by the GloVis
application. It is best to edit a copy of the original file in case
something goes wrong in the editing process.
Here is an example scene list file:
GloVis Scene List
sensor=L7 SLC-off (2003->)
ee_dataset_name=LANDSAT_ETM_SLC_OFF
LE70290302012135EDC00
LE70290302012087EDC00
LE70290302011276EDC00
sensor=Landsat 4-5 TM
ee_dataset_name=LANDSAT_TM
LT50290302011300PAC01
sensor=L1B US Day (VNIR/SWIR/TIR)
ee_dataset_name=LPDAAC_ASTER
AST_L1B.003:2080854400
The first line indicates the file is a GloVis scene list file.
The second line indicates the dataset for the following scenes.
The third line indicates the EarthExplorer (EE) dataset_name.
(This line may be absent from Scene Lists saved prior to GloVis 8.11.
The ee_dataset_name is not required for lists used only in GloVis.)
Each subsequent line is interpreted as a scene id until the next
"sensor=" line is found. The dataset name for a "sensor=" line is the same
name that shows up in the collection menu of the GloVis application.
Download Visible Browse &
Metadata
The user can download the original browse image files and metadata
information files for the scenes currently visible on the display. The
search limits dialog and user defined area can be used to limit the visible
scenes.
When the user selects this option, a dialog box is displayed that allows
the user to select the folder for storing the downloaded files. The user
may enter the required information and press the "Save" button, or cancel
by pressing the "Cancel" button. After pressing the save button, the
application downloads the original browse image files and metadata files
and writes them to the selected folder.
Download Path & Row Browse &
Metadata
The user can download the original browse image files and metadata
information files for the scenes that intersect the center cell of the
mosaic. Only scenes that meet the current search limits are downloaded.
Note that for datasets such as Landsat and MODIS, all the scenes in the
center cell that meet the current search limits are downloaded, not just
the one that is currently visible.
When the user selects this option, a dialog box is displayed that allows
the user to select the folder for storing the downloaded files. The user
may enter the required information and press the "Save" button, or cancel
by pressing the "Cancel" button. After pressing the save button, the
application downloads the original browse image files and metadata files
and writes them to the selected folder.
Download Scene List Browse &
Metadata
The user can download the original browse image files and metadata
information files for the scenes in the current scene list.
When the user selects this option, a dialog box is displayed that allows
the user to select the folder for storing the downloaded files. The user
may enter the required information and press the "Save" button, or cancel
by pressing the "Cancel" button. After pressing the save button, the
application downloads the original browse image files and metadata files
and writes them to the selected folder.
Provides a list of suggested browser and software requirements, and describes
any known problems associated with particular browsers and/or operating
systems.
Provides a link to a web site that allows downloading the source code
used to produce the USGS Global Visualization Viewer web site. This code will
only be of interest to people interested in creating similar web sites.
GloVis offers a few features that advanced users my find helpful.
These features change the way GloVis starts by modifying the URL.
To start GloVis on a different dataset, add collection=NAME or dataset=NAME
to the URL, as in the examples below.
http://glovis.usgs.gov?collection=GLS
http://glovis.usgs.gov?dataset=MYD11A1DAY
If both collection and dataset are supplied,
the collection will be ignored. If only the collection is
supplied, GloVis will start on the first dataset within that collection.
To show only one collection in the Collection menu, add
limitcollections=TRUE, as in the example below. This parameter
is generally combined with a collection parameter.
To start GloVis at a different geographic location, use
lat=LATITUDE and lon=LONGITUDE in the URL, as in the examples below:
http://glovis.usgs.gov?lat=51.5&lon=-0.2
http://glovis.usgs.gov?lat=-33.88&lon=151
Latitude and Longitude must be supplied in decimal degrees.
To start GloVis with a "pop-out" window rather than having the
Browse Image Viewer embedded in the browser window, use popout=TRUE,
as in the following example:
http://glovis.usgs.gov?popout=TRUE
The URL parameters above may be combined as in the example below.
No spaces are allowed. Invalid parameter names or values will be ignored.
These features will be most useful for researchers who regularly
study a particular area or use a particular dataset, or those who
would like to provide a more specific link to the GloVis site.
The GloVis applet does not update the browser URL; the browser URL
will always show the starting parameters for the site.
Most users may safely ignore the advanced URLs above.
A: As your cursor is passed over the locator map or any browse
image, the geographic location is reported in the browser status bar (lower
left margin of the Browse Image Viewer). The latitude and longitude is
displayed in decimal degrees. For the locator map, the path and row (or
tile number) under the cursor is also listed.
Q: Why such long response times?
A: Loading nine Landsat graphic images of 30-40K each, or dozens
of ASTER graphic images of 5K each, may take from a few seconds up to 1.5
minutes, depending upon your internet connection. Once a set of browses has
been cached, the response time should improve. You may
continue interacting with the viewer while images are being downloaded.
Q: Why do some images appear to be tilted sideways?
A: This is an artifact of the Lambert Azimuthal Equal Area
projection, which will produce more skewing near the edges of a region.
Just remember that for any scene, the up-arrow moves from one row to the row
above it, and not necessarily towards the top of your page.
In the Map Layers menu, the North Arrow will show where "north" is
relative to the mosaic or image shown.
Q: Why do the scenes sometimes look misaligned in the
mosaic view?
A: The browse scenes used to create the Global Visualization
inventory only have approximate geographic information available. This
sometimes leads to inaccurate placement of the scenes.
Q: Why do some scenes appear to be "missing"?
A: There are several possible reasons:
Landsat:
The satellite does not acquire some areas of the world. For
example, the Landsat program does not typically acquire data over
oceans.
The viewer will only display scenes that exist in the USGS archive.
For many locations outside the U.S., there may be scenes that were
collected by the sensor but the data is not archived or distributed by
USGS EROS. These scenes may still be available from other
International Ground Stations. (Please note that this data is not
a product of USGS EROS; therefore, the price, available formats,
and/or processing options may vary according to the data provider.)
Please see the
Landsat FAQ for details on searching for and ordering
Landsat scenes.
ASTER and EO-1:
ASTER and EO-1 scenes are typically collected on-demand. The
programs do not attempt to get full coverage like the Landsat
program.
Lambert Azimuthal Equal Area Regions:
For Landsat, ASTER, and EO-1,
different regions of the world are displayed using different
parameters for the Lambert Azimuthal Equal Area projection. In the
areas where two of these regions meet, only data from one of the
regions can be displayed at a time.
Q: Why doesn't the URL update when navigating, and why
can't I save a bookmark that shows the viewer window that was last displayed
when the bookmark was created?
A: The BrowseViewer is an independent Java applet, so any actions
within the applet (such as selecting a new location, selecting a new
date, and changing the viewing mode) will not ever affect the main URL to
which the browser is pointed.
Q: How can I print or save a browse image?
A: If you want to print a single browse image, the best way is
probably to use the "Show Browse" feature to open a separate window which
will allow the user to print and/or save the browse image. Metadata can be
printed in the same way using the "Show Metadata" feature. The original
browse images and metadata can be downloaded using the options in the File
menu. There is also a print option under the Tools menu that will print
the entire Browse Image Viewer area.
Q: Why did my requested scenes fail to process?
A: Technical issues can prevent scenes from processing
successfully. These images will be removed from the online catalog. In
the future, there will be investigations into these failures. If a
solution is found, the scene will be added back into our online archive.
Most of the rejected scenes are the result of a paucity of Payload
Correction Data (PCD). This ancillary data includes information that
accompanies the scenes - location of spacecraft during acquisition,
spacecraft pointing information, amount of jitter in the spacecraft, etc.
Q: Why do latitude and longitude grid lines sometimes
appear in the water map layer?
A: The source used by GloVis for the water map layer contains the
latitude and longitude grid lines. In the future, we may be able to locate
a data source that does not contain the grid lines.
Q: Why does the Shopping Cart, Metadata, or Browse
Image fail to appear when I click the 'Send to Cart'
'Show Metadata', or 'Show Browse' buttons?
A: This is usually caused by a browser or 'add-on' security
product that incorrectly blocks pop-up windows that it should not be
blocking. In GloVis, the shopping cart, metadata, browse image, and
other windows can be affected by this. Refer to your browser or add-on
security product documentation to learn how to disable the pop-up blocking
for the GloVis web site. The following products have been known to cause
problems:
Windows XP Service Pack 2 added pop-up window blocking to Internet
Explorer.
The "Google search bar" that can be added to browsers has an option
to prevent pop-up windows from appearing.
Some 'add-on' security products (like Norton Internet Security and
others) have a feature to block pop-up windows.
Note: Some of the products allow temporarily bypassing the pop-up
blocker by holding down the "Control" key when clicking on a button that
pops up a window.
Q: Why do the dates for some of the MODIS images on
GloVis not correspond with imagery for the same date provided through the MODIS
Rapid Response System?
A: The data from the Rapid Response System (rapidfire) site
are daily data collections. The MODIS products on GloVis are a collection
of both daily and composite products.Refer to the
About Browse page for a description of
which datasets are daily and which are composites. As the daily data and
multi-day composites are different products, they won't look the same and
the dates won't be the same. The date that appears in the Scene
Information field for daily data is the acquisition date, but for
multi-day composites it is the first date of the collection period.
Q: Why do I get a page indicating I need a newer
version of Java?
A: GloVis requires Java 1.6 or newer. If the version of Java
detected is older than that, the web page may display a notice indicating a
new version of Java needs to be installed. Note that some browsers do not
allow the web page to properly detect the version of Java.
Q: If I update to a newer version of Java, will it
erase my existing version of Java?
A: No. It installs a newer version of Java while leaving the
existing versions intact. This is useful for a site that has only certified
their application on an earlier version, and another site that requires a
newer version.
Q: How do I download Imagery?
A: When the "Downloadable" message is shown in the image display
area, the full resolution data may be downloaded at no charge. To
download the imagery, first select (click on) the scene you would like to
download. Then on the bottom portion of the left panel under 'Scene List',
click 'Add' and the scene will be added to the list. The scene will be
highlighted in the 'Scene List' box, and the 'Send to Cart' button will
become available. The 'Send to Cart' button will add scenes in the
current scene list to your Shopping Cart. Scenes may be added to the
Orders area the Downloads area, or both, depending on the scene's status
and which formats are available for immediate download.
Q: Why can't I order ASTER On-Demand Products
from GloVis?
A: Effective July 29, 2009, the LP DAAC implemented a change
to ASTER data access due to contractual agreements between NASA and the
Japanese owners of the ASTER sensor. If you are not an "Approved User",
you can purchase ASTER data from Japan's
Earth Remote Sensing Data Analysis Center (ERSDAC).
Detailed information about ASTER data access and approval levels can be
found on the ASTER Policies page.
Q: Why can't I order ASTER data?
A: Effective July 30, 2009, the Land Processes (LP)
Distributive Active Archive Center (DAAC) maintains a full
archive of ASTER Level 1A data open to all users for searching
and browsing through
Reverb
and the Global Visualization Viewer (GloVis). However, orders
will only be accepted from authorized Educational, NASA-Affiliated,
and Federal users as defined in the
LP DAAC ASTER Policies.
All other users are encouraged to access ASTER data from the
Earth Remote Sensing Data Analysis Center (ERSDAC) ASTER
Ground Data Station (GDS) Web site.
Q: Do I have to register with the ERSDAC website
to receive ASTER data?
A: This interface requires customers to register or create a
user name and password for use when ordering data. You may access
the on-line user registration from the Web link provided above.
Please read the "Agreement for Distribution and Use of ASTER
Products" document carefully as it differs from that of the
Land Processes DAAC.
Please note that you will receive an e-mail confirmation of the
registration information including your user name and password.
It is recommended that you keep this e-mail for future use as
passwords are managed by the users themselves. (Please also check
your SPAM filter for that message.)
Q: Are there help documents available at the
ERSDAC Web site?
A: Once you are successfully registered, please take a moment
to review the tutorial by clicking the Help button in the upper
right corner of the ASTER GDS IMS screen. Additional step-by-step
guidance for requesting ASTER products distribution is provided in
the manual linked below.
Several browse-specific questions are answered on the
About Browse page.
Contact Customer Services
Customer Services
U.S. Geological Survey
Earth Resources Observation & Science Center (EROS)
47914 252nd Street
Sioux Falls, SD 57198-0001
Tel: 800-252-4547
Tel: 605-594-6151
Fax: 605-594-6589
Email: custserv@usgs.gov
Business Hours: Monday thru Friday, 8:00 a.m. to 4:00 p.m., central time
U.S. Department of the Interior |
U.S. Geological Survey