Geog 121 Project 4: Finding LandSat Data

Geog 121 Project 4:Finding LandSat Data Shawn R. Gill Mark J. ImperialLawrence Herrighty Jr. Carolyn S. Fish Richard K. Naffin

History Behind LandSat • Originally called the Earth Resource Technology Satellite Program • Launched the first satellite, ERTS-1 in 1972. • In 1975, NASA renamed the program Landsat • There have been six successful Landsat launches (with the exception of Landsat 6). • Landsat 7 was successfully launched in 1999. • The next Landsat satellite is projected to be launched in 2010.

What Exactly Is Landsat? • Landsat is used to observe the surface of the Earth through the use of thermal infrared and visible light satellite images with a resolution of 60 meters. • It is one of the most accurate imagery tools available. • The primary goal of Landsat 7 is to continually update the archives of satellite images of Earth.

How to Find a LandSat Image • First, go to http://earthexplorer.usgs.gov. • Enter the site by clicking on ‘guest’.

‘Spatial Coverage’ Directions • Under ‘Spatial Coverage’, go to ‘Enter Place Name’ • Then, enter your town’s name and select your state. • Then, press search. • Then, simply select your town out of the list. • After selecting town, close all the pop-up windows. • The coordinates of your town will appear under ‘Spatial Coverage’.

‘Data Set Selection’ Directions • Under ‘Data Set Selections’, click on the ‘+’ in front of ‘Satellite Imagery’. • Then, click on ‘LandSat 7 ETM+ SLC off. (July 2003 to present)’ • Then, click ‘continue’.

Cloud Coverage • On the next screen, go down to ‘Cloud Cover’ and select “Less than 10%”. • Click ‘Search’. • Once the status turns from ‘Running’ to ‘Complete’, hit the results icon.

Selecting Correct Image • Choose the image file with a ‘normal’ classification and cloud cover of ‘0’ • In the below example, choose row 3.

To Find Metadata • Under ‘Show All Fields’, select ‘show’ to open up the Metadata file for row 3. • Save the opened file directly under your ‘www’ folder. • Afterwards, you can create a hyperlink to that file in order to open it from your project webpage.

This Is The Metadata File.

Downloading the Image • Under ‘Preview Image’, select the icon ‘show’ to display the satellite image. • Unselect ‘Show Grid’ to remove the yellow lines. • Then save the photo in your ‘Image’ folder using the usual techniques.

The Landsat Image

Now You Can Create Your Project Page

Why the Lines? • An Instrument malfunction occurred on Landsat 7 on May 2003. • The failure occurred with the Scan Line Corrector, which compensates for the satellites continuous forward motion while in orbit. • The lines are data gaps roughly the size of 400 meters. • Most of the data errors are along the edges of the image.

What is WRS Path and WRS Row? • WRS is the ‘Worldwide Reference System’. • WRS Path refers to the orbit number of satellite (WRS equivalent of latitiude). • WRS Row refers to the scene center number of image (WRS equivalent of longitude). • Landsat 7 uses WRS-2, with a 16 day repeat cycle (it is basically the orbit). • WRS grid is comprised of 233 paths and 248 rows.

WRS-2 Path/Row

Info For Project • All the information for the rest of the write-up can be found in the linked metadata file. • Prices can be found at http://earthexplorer.usgs.gov. under ‘prices’.

To see a copy of this presentation, go to:http://www.personal.psu.edu/rkn107.

Works Cited • http://landsat.usgs.gov • http://earthexplorer.usgs.gov. • http://campus.esri.com • http://en.wikipedia.org/wiki/landsat • http://landsat.gsfc.nasa.gov. • http://landsathandbook.gsfc.nasa.gov/handbook.html

Geog 121 Project 4: Finding LandSat Data