Landsat Presented to Silva Carbon July 31, 2012
Landsat • Homepage: http://landsat.usgs.gov History/Sensors/Resolutions • Landsat 1= 1972 MSS (60 meter resolution), WRS 1 • Landsat 2 = 1975 MSS (60 m), WRS 1 • Landsat 3 = 1978 MSS (60 m), WRS 1 • Landsat 4 = 1982 MSS (60 m), TM (30 m), WRS 2 • Landsat 5 = 1984 MSS (60 m), TM (30 m), WRS 2 • Landsat 7 = 1999 ETM+ (30 m), WRS 2
Landsat 7 ETM+ SLC -off • On May 31, 2003, the Scan Line Corrector (SLC), which compensates for the forward motion of Landsat 7, failed. All L7 scenes collected after this date will have data gaps. • The SLC-off effects are most pronounced along the edge of the scene and gradually diminish toward the center of the scene. • The middle of the scene, approximately 22 kilometers wide, contains very little data loss.
Landsat 7 ETM+ SLC –off (cont.) • About 22 percent of any given scene is lost because of the SLC failure. • The maximum width of the data gaps along the edge of the image would be equivalent to one full scan line, or approximately 390 to 450 meters. • The precise location of the missing scan lines will vary from scene to scene.
Options to gap-fill L7 SLC-off images • http://landsat.usgs.gov/using_Landsat_7_data.php • There are methods available that allow users to fill the gaps of Landsat 7 data to create an aesthetic nice-looking image. There are also methods that better maintain the integrity of the data, to create an image better suited for scientific interpretation and analysis.
Useful Tools • http://landsat.usgs.gov/tools_featured.php • EarthNow! = http://earthnow.usgs.gov • LandsatLook Viewer = http://landsatlook.usgs.gov • Spectral Viewer= http://landsat.usgs.gov/tools_viewer.php • Metadata Service= http://landsat.usgs.gov/consumer.php
Landsat Acquisition Information • http://landsat.usgs.gov/tools_acq.php • Landsat 7 is currently the only satellite acquiring new collects • 16 day revisit cycle • Calendar: http://landsat.usgs.gov/tools_L7_acquisition_calendar.php • Acquisition Archive: • http://landsat.usgs.gov/tools_pend_acq_l7.php
Landsat Acquisition Information (cont.) • Landsat 5 TM – last full acquisitions November 2011
Landsat Radiance/Reflectance Info • http://landsathandbook.gsfc.nasa.gov/data_prod/prog_sect11_3.html • Landsat Data Users Handbook: http://landsathandbook.gsfc.nasa.gov/
LDCM Data Products Info • http://landsat.usgs.gov/LDCM_DataProduct.php • Band Designations – All sensors: • http://landsat.usgs.gov/band_designations_landsat_satellites.php
Landsat Project Documentation • http://landsat.usgs.gov/tools_project_documents.php
GloVis • http://glovis.usgs.gov • Collections (default: L4-7 Combined) • Resolutions • Map Layers • Tools Level 1 T (terrain corrected) data products recommended by Professor Woodcock: L1T product listed as you page through scenes right-click to Show Metadata to show Data Type Level 1 SLC off data gaps will be considered as missing data, as clouds and shadows, so these scenes may be useable also
GloVis (cont.) • Immediately downloadable scenes = red text “Downloadable” • Scenes that are not immediately downloadable – processing request required (no charge, 1-2 day processing time)
EarthExplorer • http://earthexplorer.usgs.gov
Questions? • Landsat Customer Service • http://landsat.usgs.gov/contactus.php