Earth Resources Observation and Science Center (EROS)


USGS Global Visualization Viewer: User Guide

Contents:

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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.

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USGS Global Visualization Viewer: Home Page

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. The latest version of Java from java.com is strongly recommended.

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.

Trivia: the background image in the page banner is derived from Landsat 7 scene LE70290302002315EDC00, showing Gavins Point Dam near Yankton, South Dakota.

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.

Navigation Controls

The left side of the Browse Image Viewer has various naviation controls that are explained in the following paragraphs.

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.

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):

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.

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 the GloVis applet was granted sufficient privileges by activating/enabling the Java applet.

What's New!

Describes all modifications and improvements included within the current release of the USGS Global Visualization Viewer.

Quick Start Guide

Provides a brief overview on using the USGS Global Visualization Viewer.

Browser Requirements

Provides a list of suggested browser and software requirements, and describes any known problems associated with particular browsers and/or operating systems.

User Guide (This page)

Provides general user information on controls, navigation, and functionality of the USGS Global Visualization Viewer.

About Browse Images

Provides information and Frequently Asked Questions (FAQs) regarding the USGS Global Visualization browse displays.

Download Source Code

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.

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Tips for Advanced Users

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.

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:

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:

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.

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Frequently Asked Questions (FAQs)

Q: Where is the geographic location displayed?

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:
    1. The satellite does not acquire some areas of the world. For example, the Landsat program does not typically acquire data over oceans.
    2. 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:
    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:
    1. 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 7 or newer. If your version of Java is older than that, the web page may display a notice indicating a new version of Java needs to be installed. Some browsers do not allow the web page to properly detect the version of Java. The latest version of Java is strongly recommended. Go to java.com and click "Do I have Java?" to verify that your Java is up to date.

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 JSpacesystems ASTER/PALSAR Unified Search page. 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 JSpacesystems ASTER/PALSAR Unified Search page.

Q: Do I have to register with the JSpacesystems ASTER/PALSAR Unified Search 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 JSpacesystems ASTER/PALSAR Unified Search Web site?

A: There is a detailed ASTER/PALSAR Unified Search Site User's Manual available from the left column under the heading, "Documents," or direct access via this URL.

Q: Will the LP DAAC continue to support ASTER Data Acquisition Requests (DARs)?

A: The LP DAAC and US ASTER Team will continue to support data acquisition requests through the ASTER DAR Tool.

Q: Will ASTER L1B Data be available from the Land Processes DAAC Data Pool?

A: Yes, the LP DAAC Data Pool will remain available to all users for access to all archived ASTER Level-1B data over the U.S. and US Territories.

Q: What is this survey that pops up sometimes?

A: Please refer to the USGS Website for an explanation of the survey and how it is used.

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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

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Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://glovis.usgs.gov/ImgViewerHelp.shtml
Contact Information: custserv@usgs.gov | ASTER and MODIS questions: lpdaac@usgs.gov
Page Last Modified: 27 October 2014