Digital Spatial Data

Satellite Images

Overview

Satellite images, or remotely sensed images, are digital images recorded by digital sensors. In a digital sensor, the light is recorded directly as a digital value, making it ideal for working in the computer environment. The digital sensor uses a prism to split light into its individual components, or bands, and records the amount of photons (packets of light) in each band.

AGSL has:

Landsat 

• Title: Orthorectified Landsat Thematic Mapper (TM) Mosaics 
• Description: Obtained from GISdatadepot, the mosaics generally extend north-south over 5 degrees of latitude, and span east-west for the full width of the UTM zone. For mosaics between 60 degrees north and 60 degrees south latitude, the width of the mosaic is the standard UTM zone width of 6 degrees of longitude. For mosaics above 60 degrees of latitude, the UTM zone is widened to 12 degrees, centered on the standard UTM meridian. To insure overlap between adjacent UTM zones, each mosaic extends for at least 50 kilometers to the east and west, and 1 kilometer to the north and south.
• Coverage: AGSL has (nearly) complete worldwide data
• Resolution (pixel size): 28.5 meters
• Spectral resolution: multispectral
• Dates: 1990 +/- 3 years
• Format: MrSID
• Projection: UTM, WGS84
• Access constraints: None

Landsat tools:
Path and row shapefiles: http://landsat7.usgs.gov/wrsprshape.php
path and row to lat and long converter: http://landsat7.usgs.gov/wrsconvert/index.html

 Landsat - Great Lakes 

• Title: Great Lakes Forest Information Center, North American Landscape Characterization (NALC) dataset
• Description: Obtained from GLFIC, the NALC data set is comprised of hundreds of triplicates (i.e., multispectral scanner (MSS) data acquired in the years 1973, 1986, and 1991 plus or minus one year, thus, the name triplicate). See more info about NALC.
• Coverage: AGSL has Great Lakes region data
• Resolution (pixel size): 30 m
• Spectral resolution: multispectral
• Dates: varies (1973, 1986, & 1991)
• Format: IMG (Erdas Imagine 8.3 file format)
• Projection: N/A
• Access constraints: None
• Index Map

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 Landsat: Univ. of Maryland, Global Land Cover Facility (GLCF) (web) 

http://glcf.umiacs.umd.edu/index.shtml

• Title: The Global Land Cover Facility (University of Maryland)
• Description: The Global Land Cover Facility has the largest free LANDSAT satellite imagery.  
• Coverage: Worldwide data available for downloading
• Resolution (pixel size): Varies
• Spectral resolution: Varies
• Dates: varies
• Format: Varies
• Projection: Varies
• Access constraints: None

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 SPOT 

• Title: SPOT
• Description: Obtained from Spot Image inc., this BIL image file covers the entire City of Milwaukee.
• Coverage: AGSL has Milwaukee data
• Resolution (pixel size): 10 meters
• Spectral resolution: Multispectral & panchromatic
• Dates: June 1987 & June 1997 (Panchromatic); August 1988 & July 1997 (Multispectral)
• Format: BIL
• Projection: State Plane WI South, NAD83
• Access constraints: Available to students, faculty, and staff of the UW-Milwaukee for educational purposes

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IKONOS 

• Title: IKONOS
• Description: Obtained from Space Imaging inc., these GeoTIFF image files covers the entire City of Milwaukee, and part of Ozaukee County.
• Coverage: AGSL has Milwaukee, Grafton & Belgium (Ozaukee Co) data 
• Resolution (pixel size): 4 meters
• Spectral resolution: Multispectral (Blue, green, red, & near-infrared)
• Dates: July 2000
• Format: GeoTIFF
• Projection: UTM, WGS84 (zone 16N)
• Access constraints: Available to students, faculty, and staff of the UW-Milwaukee for educational purposes

For assistance in finding and obtaining satellite imagery, please send email to gisdata@uwm.edu. Or please check our Wisconsin data page to check data availability of the Wisconsin counties.

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Comments for the AGSL? Send them to agsl@uwm.edu.