Transcript Geog 121 Project 4: Finding LandSat Data Shawn R. Gill Mark J. Imperial

Geog 121 Project 4:
Finding LandSat Data
Shawn R. Gill
Mark J. Imperial
Lawrence 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 writeup 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
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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/han
dbook.html