In this lesson, we will discuss the basics of using EarthExplorer, an online tool that
serves as an interface to access earth science data from the archives of the USGS.
EarthExplorer provides online search, browse display, metadata export, and data download
for earth science data from the archives of the USGS. EarthExplorer is your window
into the world’s largest civilian collection of images of the Earth’s surface. This includes
Landsat 8 images of the Earth, high resolution orthoimagery, national topographic and bathymetric
datasets, Landsat-derived National Land Cover Database and natural color images from the
moderate resolution imaging spectroradiometer on NASA’s Terra satellite.
After completing this lesson you will be able to register and setup your profile, use the
EarthExplorer interface, select datasets and setup search criteria, perform a search and
view selected datasets and download files, including bulk download.
Let’s start with an introduction to EarthExplorer. The U.S. Geological Survey's Long Term Archive
at the National Center for Earth Resource Observations and Science (EROS) in Sioux Falls,
South Dakota is one of the largest civilian remote sensing data archives. It contains
a comprehensive record of the Earth's changing land surface. Scientists from around the world
depend on this archive to conduct research on changes that affect our environment, resources,
health, and safety. Time series images are a valuable resource for scientists, disaster
managers, engineers, educators, and the general public. USGS EROS has managed, archived and
preserved land remote sensing data going back 30 years and is a leader in preserving land
remote sensing imagery. Explore the world’s largest civilian collection
of images of the Earth’s surface. Find satellite images and data, aerial photography, elevation
and land cover datasets, digitized maps, and our Image Gallery collections. Our Archive
spans from 1937 aerial photographs to satellite images of the Earth’s surface, starting
with the original Earth orbits in the 1960’s and first Landsat satellite in 1972, to our
current hourly additions of satellite images. The Earth Explorer Web site provides access
to millions of land-related products, including satellite images from Landsat, advanced very
high resolution radiometer and Corona data sets, aerial photographs from the National
Aerial Photography Program, NASA, and USGS data sets, digital cartographic data from
digital elevation models, digital line graphs, digital raster graphics, and digital orthophoto
quadrangles. Before you learn how to register, let’s
take a look at the EarthExplorer interface. The EarthExplorer user interface provides
the overall capability for users to interact with the EarthExplorer components and services.
The EarthExplorer user interface is composed of the menu bar and the body of the EarthExplorer
interface The EarthExplorer menu bar supplies a common
starting point to access additional functionality, options, and preferences for the EarthExplorer
client via dropdown menus. The common menu items in the menu bar include
home, which returns you to a common starting point within the application. Login is the
link to the EarthExplorer Login. The Register tab takes you the EarthExplorer Registration
Service. We will discuss registration in detail later.
RSS feeds allow you to receive updates when new data is ingested into EarthExplorer. Data
set feeds are currently limited to data sets that actively ingest new data. For these feeds,
the most recent 2,500 scenes are returned.
You can provide feedback by clicking on the link to the feedback form. Help provides information
about EarthExplorer. Additional menu bar items display to the right
of the home tab when you register or log in. These options are described in further detail in
future parts of this lesson. The body includes the main EarthExplorer capabilities
and is composed of the Data Search Functions and the Google Map components.
The Data Search components are divided among 4 tabs and allows users to enter search criteria,
select datasets to query, enter additional criteria, and review results in a tabular
window. A detailed discussion on the Data Search functions are provided later in this
lesson. The Google Map component is located on the
right side of the EarthExplorer body element. The Google Map application interface embeds
Google Maps within the EarthExplorer client. The Google Map is a useful tool for controlling
the map, defining a search area and for verifying that results fall in the area of interest.
The Google map updates the coordinate values as you move the mouse on the map interface.
You can change the display from degrees/minutes/seconds to decimal latitude/longitude on the Coordinates
tab in the Search Criteria, here. The Options tab allows you to auto-center
the map on the display or select Polygon to enter search criteria by polygon. You can
then clear the search criteria by clicking on the Clear Criteria button in the upper
right corner below the tool bar.
Select Circle to enter search criteria by clicking on the map twice to define a center
and radius. You can also enter coordinates and a circle radius in the interface
Details on using the polygon and circle search criteria will be presented later in this lesson.
Overlays displays a grid based on the selection. Decimal overlays a decimal degree grid over
the map interface. DMS overlays Degrees, Minutes, Seconds grid over the map interface. Map/Satellite
toggles between the Map View and the Satellite View. On the Map View you can click on Terrain
to show basic topographic features. On Satellite View you can click on Labels to turn labels
on or off.
Next, we will show you how to register with EarthExplorer and logon to use all the advanced
features of the application. To register, select the ‘Register’ item from EarthExplorer
menu bar. The Registration process requires users to
create a username and password, and enter a security code. Once registered with EarthExplorer,
only the ‘Login’ process is required in future sessions. You must be sure to confirm
your password before continuing your registration and to follow the guidelines for both the
username and the password requirements. You can click the link shown here for privacy
policy information and terms of use. The Contact Demographic page allows you to
enter your affiliation and identify uses of the data. This information is used to gather
statistics on data applications and types of organizations using remotely-sensed data.
Enter your address and other contact information in the Contact Information page. The address
information is not only used for contact information, however, as some data products require shipping
information to deliver products. Address information is not shared with any commercial
or other government agencies. Confirm the information you’ve entered on
the Complete Registration page and click Submit Registration when complete. An email will
be sent to you to confirm that your account has been activated. Once you’ve confirmed
your account, you can return to the EarthExplorer main page to login.
A registered user can use all of EarthExplorer's features, including saving search criteria,
downloading data, and accessing subscription services.
To log in, select the 'Login' menu item from the EarthExplorer menu. Type your username
and password and then click the 'Sign In' button.
Once logged in, additional items appear in the main menu bar that will be discussed later.
By hovering over your username, you will see additional options related to your account.
The Profile option allows users to modify profile information. This includes contact
information, demographic information and you can also change your password here, as well.
The Settings option allows users to modify information associated with the overall system
interface. Note that the profile information shown here must be changed in the Profile
information we just discussed, which can be accessed by clicking this link.
By clicking on Interface options you can modify the number of metadata results per page, the
set size, auto center the map and enable bulk download.
The data sets tab allows you to modify the list of datasets shown in the Data Sets Component
of your searches. By default all the datasets in EarthExplorer will be visible for selection
during your searches. You can narrow future searches by unchecking data sets you are not
interested in. Sort Order modifies the sort order for each
dataset. For example if you want NHAP to be sorted by ascending acquisition dates, click
on the collection drop down list and click on aerial imagery: NHAP. Click on result metadata
then the drop down next to acquisition date and select ascending or descending. Then click
Save once you are finished. Other profile options, item basket options,
the saved criteria, standing request, order tabs and CIDR tracking, will be discussed
later in this lesson. The Metadata View option is currently inactive.
To log out of EarthExplorer, hover over your username in the menu bar and select logout.
In this lesson, we discussed the basics of using EarthExplorer, including the interface
and setting up a profile. Next, lesson 7b will cover entering search criteria.