GEOG 121 Project 4:GEOG 121 Project 4:Finding Landsat DataFinding Landsat Data

Presented by:Presented by:Dan LaSotaDan LaSota

Greg StrickerGreg StrickerWeiqiang LinWeiqiang Lin

About Landsat: PurposeAbout Landsat: Purpose

The Landsat Program is established to acquire remote sensing The Landsat Program is established to acquire remote sensing imagery of the earth for monitoring and managing the Earth's imagery of the earth for monitoring and managing the Earth's resources. resources.

Applications include: agriculture, geology, forestry, regional Applications include: agriculture, geology, forestry, regional planning, education, national security and global climate change planning, education, national security and global climate change research. research.

Landsat 7 is the most recent NASA satellite among 6 others that Landsat 7 is the most recent NASA satellite among 6 others that have produced a continuous multispectral record of the Earth's land have produced a continuous multispectral record of the Earth's land surface for 32 years now. surface for 32 years now.

Special Emphasis on: Currency, accuracy, affordability and public Special Emphasis on: Currency, accuracy, affordability and public accessibility of Landsat Data.accessibility of Landsat Data.

It is used across disciplines to achieve improved understanding of It is used across disciplines to achieve improved understanding of the Earth's land surfaces and the impact of humans on the the Earth's land surfaces and the impact of humans on the environment. environment.

About Landsat: Brief HistoryAbout Landsat: Brief History NASA initiated an Earth Resources Survey (ERS) Program 1965 to NASA initiated an Earth Resources Survey (ERS) Program 1965 to

develop methods for remote sensing of earth resources from space. develop methods for remote sensing of earth resources from space. First Earth Resources Technology Satellite (Landsat 1) launched in 1972 First Earth Resources Technology Satellite (Landsat 1) launched in 1972

with two Earth-viewing sensing systems with two Earth-viewing sensing systems – a return beam vidicon (RBV) – discontinued after Landsat 3 and a return beam vidicon (RBV) – discontinued after Landsat 3 and – an 80 meter multispectral scanner (MSS). an 80 meter multispectral scanner (MSS).

Original MSS measures radiation within four narrow bands that span Original MSS measures radiation within four narrow bands that span visible green wavelengths, visible red wavelengths, and slightly longer, visible green wavelengths, visible red wavelengths, and slightly longer, near-IR wavelengths.near-IR wavelengths.

Landsat 4 launched in 1984 with the MSS and the Thematic Mapper (TM) Landsat 4 launched in 1984 with the MSS and the Thematic Mapper (TM) featuring higher spatial resolution (30 meters) and improved spectral featuring higher spatial resolution (30 meters) and improved spectral sensitivity (7 bands, including visible blue, two mid-infrared, & thermal sensitivity (7 bands, including visible blue, two mid-infrared, & thermal infrared wavelengths). infrared wavelengths).

The Landsat 7 Enhanced Thematic Mapper Plus (ETMThe Landsat 7 Enhanced Thematic Mapper Plus (ETM++) Sensor was ) Sensor was launched in Apr 1999, with improved resolution and precision, necessitated launched in Apr 1999, with improved resolution and precision, necessitated by the high costs of imaging, Land Remote Sensing Policy Act (1992) and by the high costs of imaging, Land Remote Sensing Policy Act (1992) and the loss of Landsat 6. the loss of Landsat 6.

Landsat is a tri-agency joint program of NASA, NOAA and the USGS. Landsat is a tri-agency joint program of NASA, NOAA and the USGS.

About Landsat: About Landsat: Satellite CharacteristicsSatellite Characteristics

Source: http://ltpwww.gsfc.nasa.gov/IAS/handbook/handbook_htmls/chapter1/chapter1.html#section1.1

About Landsat: How it works? About Landsat: How it works? Space SegmentSpace Segment

The ETM+ sensor onboard the spacecraft obtains data along the ground The ETM+ sensor onboard the spacecraft obtains data along the ground track at a fixed swath (185 km in width). track at a fixed swath (185 km in width).

The orbit of Landsat 7 is repetitive, circular and near polar at a nominal The orbit of Landsat 7 is repetitive, circular and near polar at a nominal altitude of 705 km (438 miles) at the Equator. altitude of 705 km (438 miles) at the Equator.

The spacecraft completes just over 14 orbits per day, covering the entire The spacecraft completes just over 14 orbits per day, covering the entire Earth between 81 degrees N & S latitude Earth between 81 degrees N & S latitude every 16 daysevery 16 days. .

A multispectral data set having high (30 meter) & medium to coarse (250 to A multispectral data set having high (30 meter) & medium to coarse (250 to 1000 meter) spatial resolution is acquired on a global basis repetitively. 1000 meter) spatial resolution is acquired on a global basis repetitively.

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

About Landsat: How it works? About Landsat: How it works? Ground SegmentGround Segment

Segment consists of both Landsat 7 unique components as well as Segment consists of both Landsat 7 unique components as well as institutional services. Some examples:institutional services. Some examples:– Landsat 7 Unique ComponentsLandsat 7 Unique Components

Landsat Ground Station LGS, located at EDC, in Sioux Falls, SD is Landsat Ground Station LGS, located at EDC, in Sioux Falls, SD is a receive site for the wideband X-Band downlinksa receive site for the wideband X-Band downlinks of payload data of payload data from the space vehicle.from the space vehicle.

In addition to LGS, the Alaska Ground Station & the Svalbard In addition to LGS, the Alaska Ground Station & the Svalbard Norway Ground Station receive payload data downlinks. Norway Ground Station receive payload data downlinks.

International Ground Stations are satellite data receiving stations International Ground Stations are satellite data receiving stations located worldwide. They receive, process, & distribute services.located worldwide. They receive, process, & distribute services.

– Institutional ServicesInstitutional Services Landsat Ground NetworkLandsat Ground Network provides communication support. provides communication support. Space Network – relay servicesSpace Network – relay services NASA Integrated Support Network – supports Institutional ServicesNASA Integrated Support Network – supports Institutional Services

About Landsat: ProductsAbout Landsat: Products

Level 0R Product: an essentially raw data form that is marginally useful Level 0R Product: an essentially raw data form that is marginally useful prior to radiometric and geometric correction. prior to radiometric and geometric correction.

Level 1R product is a radiometrically corrected 0R product. 1R product Level 1R product is a radiometrically corrected 0R product. 1R product & 0R at input level have identical geometry. & 0R at input level have identical geometry.

The 1G product is available to users and is a radiometrically and The 1G product is available to users and is a radiometrically and systematically corrected 0R image. systematically corrected 0R image. – Can be processed by LPGS or NLAPS Can be processed by LPGS or NLAPS

– Geometrically rectified for sensor/satellite/terrestrial distortionsGeometrically rectified for sensor/satellite/terrestrial distortions

– Scene rotated, aligned, & georeferenced to a user-defined map projection. Scene rotated, aligned, & georeferenced to a user-defined map projection.

– Earthexplorer always utilize the low gain LMAX value when scaling the Earthexplorer always utilize the low gain LMAX value when scaling the radiance of a scene so that all pixels saturate at the same radiance.radiance of a scene so that all pixels saturate at the same radiance.

Others: 1P (precision corrected), 1T (terrain corrected), SLC-off Others: 1P (precision corrected), 1T (terrain corrected), SLC-off ProductsProducts

About Landsat: DistributionAbout Landsat: Distribution Landsat 7 data distribution Landsat 7 data distribution

system will provide access to system will provide access to Landsat 7 Level 0R data Landsat 7 Level 0R data products within 24 hours of products within 24 hours of collection, andcollection, and

Level 1 processed products Level 1 processed products within 48 hours of request. within 48 hours of request.

Media:Media:– Exabyte tape Exabyte tape – CD-ROM or CD-ROM or – Electronic transfer via FTPElectronic transfer via FTP

Imagery of foreign land masses Imagery of foreign land masses will be recorded to EDC at Sioux will be recorded to EDC at Sioux Falls, yet the temporal depth will Falls, yet the temporal depth will be a fraction of what's available be a fraction of what's available at the international ground at the international ground stations. stations.

What is SLC-off?What is SLC-off?

An instrument malfunction occurred onboard Landsat 7 on May 31, An instrument malfunction occurred onboard Landsat 7 on May 31, 2003. The problem was caused by failure of the Scan Line Corrector 2003. The problem was caused by failure of the Scan Line Corrector (SLC), which compensates for the forward motion of the satellite. (SLC), which compensates for the forward motion of the satellite.

The center of a SLC-off data product is very similar in quality to 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 previous Landsat 7 data. However, the scene's edges will contain alternating scan lines of missing data or duplicated data.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 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. 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 EDC has reduced the price of Landsat 7 ETM+ SLC-off scenes from $600 to $250. $600 to $250.

What is SLC-off?What is SLC-off?

What is SLC-off?What is SLC-off?

Using Landsat Data… Using Landsat Data… A Digression from SLC-offA Digression from SLC-off

How to do Project How to do Project 4 4 Generating Landsat ImageGenerating Landsat Image

To find coordinates: To find coordinates: www.census.gov/cgi-bin/gazetteerwww.census.gov/cgi-bin/gazetteerTo generate Landsat Image: To generate Landsat Image: http://earthexplorer.usgs.govhttp://earthexplorer.usgs.govClick on “Enter as: Click on “Enter as: GuestGuest””Click on “Enter Coordinates” to do so in Decimals/DDMMSSClick on “Enter Coordinates” to do so in Decimals/DDMMSSUnder Data Set Selection, check the box for Under Data Set Selection, check the box for

–““ETM+ SLC-off (Landsat 7, Jul 2003 – Present) ETM+ SLC-off (Landsat 7, Jul 2003 – Present)

Click “Continue”, then “Search” on the following pageClick “Continue”, then “Search” on the following pageWhen the search is completed, click on the Data SetWhen the search is completed, click on the Data Set

– “ “ETM+ SLC-off (Landsat 7, July 2003 - present)”ETM+ SLC-off (Landsat 7, July 2003 - present)”

Click on the “Show” button, under the column “Preview Image”, that Click on the “Show” button, under the column “Preview Image”, that corresponds to the smallest amount of cloud cover and the most recent corresponds to the smallest amount of cloud cover and the most recent image.image.

Right click to Save Picture As (e.g. jpg) for Project 4.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 Click on the “Show” button under “Show All Fields” for your image to

show metadata.show metadata. Hyperlink the metadata to Project 4 - ORHyperlink the metadata to Project 4 - OR

– Click on File and choose “Properties”Click on File and choose “Properties”

– Copy the URL for the metadataCopy the URL for the metadata

Create new page for metadata using Microsoft FrontpageCreate new page for metadata using Microsoft Frontpage– Upload it to Pass ExplorerUpload it to Pass Explorer

– Provide a link in Project 4 to this Metadata Page.Provide a link in Project 4 to this Metadata Page.

How to do Project How to do Project 4 4 Creating the ReportCreating the Report

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

Note Scene Acquisition Date for the image you have selected.Note Scene Acquisition Date for the image you have selected. The World Reference System (WRS) indexes orbits (paths) and scene centers (rows) into a The World Reference System (WRS) indexes orbits (paths) and scene centers (rows) into a

global grid system, comprising 233 paths by 248 rows. 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 The standard WRS scene as defined for Landsats 4 and 5 was preserved as a product for

Landsat 7. Landsat 7. A path distance of 90 kilometers before and after a WRS center point defines the standard scene 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 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 scenes along a path by 5% at the equator and has a width or cross track distance of 185 kilometers. kilometers.

DefinitionsDefinitions– The term row refers to the latitudinal center line across a frame of imagery along any given The term row refers to the latitudinal center line across a frame of imagery along any given

path.path.– The intersection of rows and paths produces the nominal scene center for that landsat imageThe 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. The path/row numbers do not coincide with latitudes 90° north and south.

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

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

Location and Extent of the SceneLocation and Extent of the Scene– Coordinates of the NW, NE, SW and SE corners can be found in the Coordinates of the NW, NE, SW and SE corners can be found in the

metadatametadata

Cost of actual Landsat scene that corresponds to the free browse Cost of actual Landsat scene that corresponds to the free browse image: image: – USGS Landsat ETM+ : $600.00 for first sceneUSGS Landsat ETM+ : $600.00 for first scene– USGS Landsat ETM+ SLC-Off : $250.00 for first sceneUSGS Landsat ETM+ SLC-Off : $250.00 for first scene– http://edcsns17.cr.usgs.gov/helpdocs/http://edcsns17.cr.usgs.gov/helpdocs/

prices.html#LANDSAT_ETM+prices.html#LANDSAT_ETM+

SourcesSources

NASA Landsat Program (2004) NASA Landsat Program (2004) http://geo.arc.nasa.gov/sge/landsat/landsat.htmlhttp://geo.arc.nasa.gov/sge/landsat/landsat.html

Landsat 7 Science Data Users Handbook (2004) Landsat 7 Science Data Users Handbook (2004) http://ltpwww.gsfc.nasa.gov/IAS/handbook/handbook_toc.html http://ltpwww.gsfc.nasa.gov/IAS/handbook/handbook_toc.html

U.S. Census Bureau (2000) www.census.gov/cgi-bin/gazetteerU.S. Census Bureau (2000) www.census.gov/cgi-bin/gazetteer USGS Earthexplorer (2004) http://earthexplorer.usgs.gov USGS Earthexplorer (2004) http://earthexplorer.usgs.gov USGS Landsat Project (2004) USGS Landsat Project (2004)

http://landsat.usgs.gov/programdesc.htmlhttp://landsat.usgs.gov/programdesc.html Esri Online Campus (2004) http://campus.esri.comEsri Online Campus (2004) http://campus.esri.com