GEOG%20121%20Project%204:%20Finding%20Landsat%20Data

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GEOG 121 Project 4Finding Landsat Data

• Presented by
• Dan LaSota
• Greg Stricker
• Weiqiang Lin

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About Landsat Purpose

• The Landsat Program is established to acquire
  remote sensing imagery of the earth for
  monitoring and managing the Earth's resources.
• Applications include agriculture, geology,
  forestry, regional planning, education, national
  security and global climate change research.
• Landsat 7 is the most recent NASA satellite among
  6 others that have produced a continuous
  multispectral record of the Earth's land surface
  for 32 years now.
• Special Emphasis on Currency, accuracy,
  affordability and public accessibility of Landsat
  Data.
• It is used across disciplines to achieve improved
  understanding of the Earth's land surfaces and
  the impact of humans on the environment.

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About Landsat Brief History

• NASA initiated an Earth Resources Survey (ERS)
  Program 1965 to develop methods for remote
  sensing of earth resources from space.
• First Earth Resources Technology Satellite
  (Landsat 1) launched in 1972 with two
  Earth-viewing sensing systems
• a return beam vidicon (RBV) discontinued after
  Landsat 3 and
• an 80 meter multispectral scanner (MSS).
• Original MSS measures radiation within four
  narrow bands that span visible green wavelengths,
  visible red wavelengths, and slightly longer,
  near-IR wavelengths.
• Landsat 4 launched in 1984 with the MSS and the
  Thematic Mapper (TM) featuring higher spatial
  resolution (30 meters) and improved spectral
  sensitivity (7 bands, including visible blue, two
  mid-infrared, thermal infrared wavelengths).
• The Landsat 7 Enhanced Thematic Mapper Plus
  (ETM) Sensor was launched in Apr 1999, with
  improved resolution and precision, necessitated
  by the high costs of imaging, Land Remote Sensing
  Policy Act (1992) and the loss of Landsat 6.
• Landsat is a tri-agency joint program of NASA,
  NOAA and the USGS.

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About Landsat Satellite Characteristics
Source http//ltpwww.gsfc.nasa.gov/IAS/handbook/h
andbook_htmls/chapter1/chapter1.htmlsection1.1
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About Landsat How it works? Space Segment

• The ETM sensor onboard the spacecraft obtains
  data along the ground track at a fixed swath (185
  km in width).
• The orbit of Landsat 7 is repetitive, circular
  and near polar at a nominal altitude of 705 km
  (438 miles) at the Equator.
• The spacecraft completes just over 14 orbits per
  day, covering the entire Earth between 81 degrees
  N S latitude every 16 days.
• A multispectral data set having high (30 meter)
  medium to coarse (250 to 1000 meter) spatial
  resolution is acquired on a global basis
  repetitively.

Source http//ltpwww.gsfc.nasa.gov/IAS/handbook/h
andbook_htmls/chapter5/htmls/swath_pattern.html
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About Landsat How it works? Ground Segment

• Segment consists of both Landsat 7 unique
  components as well as institutional services.
  Some examples
• Landsat 7 Unique Components
• Landsat Ground Station LGS, located at EDC, in
  Sioux Falls, SD is a receive site for the
  wideband X-Band downlinks of payload data from
  the space vehicle.
• In addition to LGS, the Alaska Ground Station
  the Svalbard Norway Ground Station receive
  payload data downlinks.
• International Ground Stations are satellite data
  receiving stations located worldwide. They
  receive, process, distribute services.
• Institutional Services
• Landsat Ground Network provides communication
  support.
• Space Network relay services
• NASA Integrated Support Network supports
  Institutional Services

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About Landsat Products

• Level 0R Product an essentially raw data form
  that is marginally useful prior to radiometric
  and geometric correction.
• Level 1R product is a radiometrically corrected
  0R product. 1R product 0R at input level have
  identical geometry.
• The 1G product is available to users and is a
  radiometrically and systematically corrected 0R
  image.
• Can be processed by LPGS or NLAPS
• Geometrically rectified for sensor/satellite/terre
  strial distortions
• Scene rotated, aligned, georeferenced to a
  user-defined map projection.
• Earthexplorer always utilize the low gain LMAX
  value when scaling the radiance of a scene so
  that all pixels saturate at the same radiance.
• Others 1P (precision corrected), 1T (terrain
  corrected), SLC-off Products

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About Landsat Distribution

• Landsat 7 data distribution system will provide
  access to Landsat 7 Level 0R data products within
  24 hours of collection, and
• Level 1 processed products within 48 hours of
  request.
• Media
• Exabyte tape
• CD-ROM or
• Electronic transfer via FTP
• Imagery of foreign land masses will be recorded
  to EDC at Sioux Falls, yet the temporal depth
  will be a fraction of what's available at the
  international ground stations.

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What is SLC-off?

• An instrument malfunction occurred onboard
  Landsat 7 on May 31, 2003. The problem was caused
  by failure of the Scan Line Corrector (SLC),
  which compensates for the forward motion of the
  satellite.
• The center of a SLC-off data product is very
  similar in quality to previous Landsat 7 data.
  However, the scene's edges will contain
  alternating scan lines of missing data or
  duplicated data.
• As of 5/10/2004, product is in 1G form and has
  the gap areas filled with Landsat 7 data acquired
  at a similar time of year prior to the failure.
• EDC has reduced the price of Landsat 7 ETM
  SLC-off scenes from 600 to 250.

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What is SLC-off?
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What is SLC-off?
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Using Landsat Data A Digression from SLC-off
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How to do Project 4 Generating Landsat Image

• To find coordinates www.census.gov/cgi-bin/gazett
  eer
• To generate Landsat Image http//earthexplorer.us
  gs.gov
• Click on Enter as Guest
• Click on Enter Coordinates to do so in
  Decimals/DDMMSS
• Under Data Set Selection, check the box for
• ETM SLC-off (Landsat 7, Jul 2003 Present)
• Click Continue, then Search on the following
  page
• When the search is completed, click on the Data
  Set
• ETM SLC-off (Landsat 7, July 2003 - present)

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How to do Project 4 Creating the Report

• Click on the Show button, under the column
  Preview Image, that corresponds to the smallest
  amount of cloud cover and the most recent image.
• Right click to Save Picture As (e.g. jpg) for
  Project 4.
• Click on the Show button under Show All
  Fields for your image to show metadata.
• Hyperlink the metadata to Project 4 - OR
• Click on File and choose Properties
• Copy the URL for the metadata
• Create new page for metadata using Microsoft
  Frontpage
• Upload it to Pass Explorer
• Provide a link in Project 4 to this Metadata Page.

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How to do Project 4 Answering the Questions

• Note Scene Acquisition Date for the image you
  have selected.
• The World Reference System (WRS) indexes orbits
  (paths) and scene centers (rows) into a global
  grid system, comprising 233 paths by 248 rows.
• The standard WRS scene as defined for Landsats 4
  and 5 was preserved as a product for Landsat 7.
• A path distance of 90 kilometers before and after
  a WRS center point defines the standard scene
  length of 180 km (includes 20 scans of overlap)
  The standard WRS scene overlaps neighboring
  scenes along a path by 5 at the equator and has
  a width or cross track distance of 185
  kilometers.
• Definitions
• The term row refers to the latitudinal center
  line across a frame of imagery along any given
  path.
• The intersection of rows and paths produces the
  nominal scene center for that landsat image
• The path/row numbers do not coincide with
  latitudes 90 north and south.

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How to do Project 4 Answering the Questions
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How to do Project 4 Answering the Questions

• Location and Extent of the Scene
• Coordinates of the NW, NE, SW and SE corners can
  be found in the metadata
• Cost of actual Landsat scene that corresponds to
  the free browse image
• USGS Landsat ETM 600.00 for first scene
• USGS Landsat ETM SLC-Off 250.00 for first
  scene
• http//edcsns17.cr.usgs.gov/helpdocs/prices.htmlL
  ANDSAT_ETM

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Sources

• NASA Landsat Program (2004) http//geo.arc.nasa.go
  v/sge/landsat/landsat.html
• Landsat 7 Science Data Users Handbook (2004)
  http//ltpwww.gsfc.nasa.gov/IAS/handbook/handbook_
  toc.html
• U.S. Census Bureau (2000) www.census.gov/cgi-bin/g
  azetteer
• USGS Earthexplorer (2004) http//earthexplorer.usg
  s.gov
• USGS Landsat Project (2004) http//landsat.usgs.go
  v/programdesc.html
• Esri Online Campus (2004) http//campus.esri.com