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Downloading and Formatting Earth Images (Landsat satellite images) from NASA for GIS UseAuthor:Joseph J. Kerski, Ph.D.Geographer: Education/GISjjkerski@usgs.govDescription:

This is a tutorial that will aid you in downloading Landsat satellite images into a GIS (such as ArcViewor ArcGIS) from the NASA Zulu site.First, access the following web site:https://zulu.ssc.nasa.gov/mrsidMore recent Landsat images can be viewed and downloaded fromhttp://landsat7.usgs.gov (althoughthe resolution is 240 meters rather than 30 meters).A good source of information about Landsat : http://landsat.gsfc.nasa.gov/Another good source for free Landsat imagery is on the University of Maryland's Global Land CoverFacility:http://glcf.umiacs.umd.edu/index.shtml

Landsat images are catalogued in parth and row. A unique path and row combination exists for eachsatellite scene covering a specific chunk of the Earth's surface. Let's say you want a specific area

and you don't want to spend time browsing the maps on the above sites; rather, you want to use theabove sites to go directly to the path and row that corresponds to the specific area on the Earth'ssurface you want to examine. The following are some sites that provide the path and row. You canuse this information to then go to the above sites and download the image(s) you need.

1) There is a shapefile which can be used with various GIS apps at:

http://landsat7.usgs.gov/wrsprshape.php

Regarding the ARC shapefile... "A" refers to ascending node, meaning the scenes are acquired as thesatellite is moving up behind the earth (dark side). These are basically night-time scenes, and aregenerally collected by the sensor only for calibration activities and/or thermal studies. Descendingnode ("D") would be the standard daytime scene reference, and these are what you probably want.

The file is in geographic (lat-long) coordinates using the WGS-84 spheroid.

2) A printable map exists on:

http://ltpwww.gsfc.nasa.gov/IAS/handbook/handbook_htmls/chapter5/htmls/wrs_graphic.html

(3) Lat-long to path-row converter:

http://landsat7.usgs.gov/wrsconvert/index.html

the little graphic is off a bit from the actual path - row, but the lat - long is correct.

(4) When searching for the path/row of a particular location, the easiest way to do this would be via

"GloVis" ( http://glovis.usgs.gov/ ), theonline search tool.

Once you enter the lat-long from the home page (or click on the map), you will immediately see amosaic of browse/preview images with the path and row displayed for the currently active scene(highlighted). Map layers may also be activated, if you need additional geographic reference. Latitudeand longitude (decimal degrees) for any point on your screen will be displayed in the lower left browserbar.The world image displayed (shown below) is overlaid with rectangles. These rectangles are referred toas mosaics or tiles. These are the downloadable images. Each tile image was captured around theyear 1990 (+/- 3 years).These satellite images enable observation of large natural features, such as volcanoes, rivers, andforests, and large man-made features. Major highways, office buildings (such as the Pentagon or US

Capitol building), city parks and agricultural fields, airports, major bridges and dams are apparent, butnarrow streets, creeks and streams, individual houses, and automobiles cannot be discerned. GISUses:

http://rockyweb.cr.usgs.gov/public/outreach/kerski.htmlmailto:jjkerski@usgs.govhttps://zulu.ssc.nasa.gov/mrsidhttp://landsat7.usgs.gov/http://landsat7.usgs.gov/http://landsat.gsfc.nasa.gov/http://landsat.gsfc.nasa.gov/http://glcf.umiacs.umd.edu/index.shtmlhttp://landsat7.usgs.gov/wrsprshape.phphttp://ltpwww.gsfc.nasa.gov/IAS/handbook/handbook_htmls/chapter5/htmls/wrs_graphic.htmlhttp://landsat7.usgs.gov/wrsconvert/index.htmlhttp://glovis.usgs.gov/http://glovis.usgs.gov/http://rockyweb.cr.usgs.gov/public/outreach/kerski.htmlmailto:jjkerski@usgs.govhttps://zulu.ssc.nasa.gov/mrsidhttp://landsat7.usgs.gov/http://landsat.gsfc.nasa.gov/http://glcf.umiacs.umd.edu/index.shtmlhttp://landsat7.usgs.gov/wrsprshape.phphttp://ltpwww.gsfc.nasa.gov/IAS/handbook/handbook_htmls/chapter5/htmls/wrs_graphic.htmlhttp://landsat7.usgs.gov/wrsconvert/index.htmlhttp://glovis.usgs.gov/

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Geographic Information System (GIS) Uses: With a GIS, you can:1) Use these images as base maps behind your field-collected coordinates. The images, as yourfield-collected coordinates using a GPS (Global Positioning System) receiver, are both in Earth-referenced coordinates. Therefore, the points you collect using your GPS will plot onto these maps.2) Time-based analysis can be accomplished by comparing images of the same area that werecaptured at different times.

3) Analyze the different spectral bands in the Landsat image to detect crop health, geology,greenness, and other characteristics of the Earth.Landsat Data Details: Coverage: The Landsat mosaics are delivered in a Universal Transverse Mercator (UTM) /World Geodetic System 1984 (WGS84) projection. The mosaics generally extend north-south over 5degrees of latitude, and span east-west for the full width of the UTM zone. For mosaics between 60degrees north and 60 degrees south latitude, the width of the mosaic is the standard UTM zone widthof 6 degrees of longitude. For mosaics above 60 degrees of latitude, the UTM zone is widened to 12degrees, centered on the standard UTM meridian. To insure overlap between adjacent UTM zones,each mosaic extends for at least 50 kilometers to the east and west, and 1 kilometer to the north andsouth.

Color representation The images are delivered in the SWIR bands.

True Color

Red:Band 3Green:Band 2Blue:Band 1

FalseColor

Red:Band 4Green:Band 3Blue:

Band 2

SWIR(GeoCover)

Red: Band7Green: Band 4Blue: Band2

Trees andbushes

OliveGreen

Red Shades ofgreen

Crops Medium tolight green

Pink tored

Shades ofgreen

WetlandVegetation

Darkgreen toblack

Dark red Shades ofgreen

Water Shades of

blue andgreen

Shades of

blue

Black to dark

blue

Urbanareas

White tolight blue

Blue togray

Lavender

Bare soil White tolight gray

Blue togray

Magenta,Lavender, orpale pink