What the dataset was used for: to estimate the change in vegetation amount over time in Wyoming. We used three Landsat Multi Spectral Scanner (MSS) images, one from the early-to-mid 1970s, one from the mid 1980s, and one from the early 1990s. Vegetation amount is determined from the Normalized Difference Vegetation Index, defined as (Band 4 - Band 2)/(Band 4 + Band 2), where Band 4 covers near-infrared (NIR) wavelengths from 0.8 to 1.1 Fm and Band 2 covers red wavelengths from 0.6 to 0.7 Fm. NDVI saturates with one-sided leaf area indices (LAI) of 4 and higher; however, this is not a problem for Wyoming grasslands and shrublands have low LAI. NDVI varies from -1 to 1, and are converted into digital numbers (DN) by: 100 (NDVI+1), so the DN varies from 0 to 200.
Change detection is estimated as the NDVI(1990) - 0.5[NDVI(1980) - NDVI(1970)] for each image, except for areas covered with snow, clouds, and shadows caused by clouds. If two dates were available for these areas, we subtracted the NDVI of the earlier date from the NDVI of the later date. The dates of acquisition were usually collected towards the end of the growing season, and usually during years of drought (for example: 1992, 1985, 1972). We have developed an algorithm using the Advanced Very High Resolution Radiometer (AVHRR) data from the EROS Data Center to adjust NDVIs to average precipitation amounts, but these corrections were not applied to this dataset.
Hunt, E. R., Jr. and M. M. Barlow., 1997, Long-term Vegetation Assessment in Wyoming using Landsat Multi Spectral Scanner (MSS) Data: Spatial Data and Visualization Center, Laramie, Wyoming.Online Links:
This is a Raster data set.
Planar coordinates are encoded using row and column
Abscissae (x-coordinates) are specified to the nearest 1
Ordinates (y-coordinates) are specified to the nearest 1
Planar coordinates are specified in meters
The horizontal datum used is North American Datum 1983.
The ellipsoid used is Geodetic Reference System 80.
The semi-major axis of the ellipsoid used is 6378137.
The flattening of the ellipsoid used is 1/298.25.
0 white (edges, no data) 1 black 2 - 72 red (large decrease in vegetation amount) 73 - 83 coral 84 - 94 yellow 95 - 105 thistle (no change) 106 - 116 green 117 - 127 cyan 128 - 255 blue (large increase in vegetation amount)There are also three-band false-color composite images showing the scene area. The three bands are MSS Band 4 (NIR) displayed as red, MSS Band 2 (red) displayed as green, and MSS Band 1 (green, 0.5 to 0.6 Fm wavelengths) displayed as blue. The dates for the false-color composite TIFF files are:
Yellowstone 08/26/92 Cody 08/19/92 Greybull 07/27/92 Sheridan 09/17/74 Sundance 09/05/91 Jackson 08/26/92 Pinedale 08/27/92 Riverton 09/30/92 Casper 09/30/92 Lusk 09/21/91 Fontenelle 07/26/92 Rock Springs 08/12/92 Rawlins 06/02/92 Laramie 07/01/75 Pine Bluffs 08/15/92
Data Manager
Spatial Data and Visualization Center
Box 4008 University Station
Laramie, Wyoming 82071
USA
307-766-2735 (voice)
n/a
- Hours_of_Service: 8 AM to 5 PM MST
This dataset was used for the purpose of estimating the change in vegetation amount over time in Wyoming.
EROS Data Center, Sioux Falls, SD, unknown, North American Landscape Characterization Landsat Multi Spectral Scanner (MSS) Triplicates.
Path 38 Row 29 (Yellowstone) 08/01/73, 08/02/86, 08/26/92 Path 37 Row 29 (Cody) 08/01/73, 08/27/86, 08/19/92 Path 36 Row 29 (Greybull) 07/25/74, 07/19/86, 07/27/92 Path 35 Row 29 (Sheridan) 09/17/74, 08/29/86, 08/29/92 Path 34 Row 29 (Sundance) 09/08/72, 09/17/84, 09/05/91 Path 38 Row 30 (Jackson) 08/15/74, 08/15/85, 08/26/92 Path 37 Row 30 (Pinedale) 08/06/72, 08/27/86, 08/27/92 Path 36 Row 30 (Riverton) 07/30/73, 07/19/86, 07/27/92 Path 35 Row 30 (Casper) 09/17/74, 10/16/86, 09/30/92 Path 34 Row 30 (Lusk) 09/08/72, 09/17/84, 09/21/91 Path 37 Row 31 (Fontenelle) 08/05/72, 08/08/85, 07/26/92 Path 36 Row 31 (Rock Springs) 08/05/72, 08/17/86, 08/12/92 Path 35 Row 31 (Rawlins) 07/01/75, 06/07/85, 06/02/92 Path 34 Row 31 (Laramie) 07/01/75, 07/02/85, 07/05/92 Path 33 Row 31 (Pine Bluffs) 08/19/72, 08/15/86, 08/15/92See the USGS metadata for Landsat MSS for more detailed description of collection and processing of the satellite imagery. <URL:http://edcwww.cr.usgs.gov/nsdi/html/landsat_mss/landsat_mss>
This attribute accuracy statement is taken from USGS metadata for Landsat MSS:
The identification of features is provided by the distinct electromagnetic energy it emits, reflects, or otherwise transmits. This is called the spectral signature. Other signatures are tone (lightnes or darkness), texture (surface roughness or smoothness), pattern, shadow, shape and size are as important. Thus, through the use of multispectral scanners, such elements as water features, soils, and vegetation can be identified and distinguished from each other.
MSS has 79 m by 79m instaneous field of view. Data were resampled to 60m by 60m, and geometrically corrected to a UTM projection 1:100,000 map scale.
This accuracy statemend is taken from the USGS metadata for Landsat MSS:
The MSS sensor scanned the Earth's surface from west to east as the satellite moved in its descending (north-to-south) orbit over the sunlit side of the Earth. Six detectors for each spectral band provided six scan lines on each active scan. The combination of scanning geometry, satellite orbit, and Earth rotation produced the global coverage necessary for studying land surface change. The resolution of the MSS sensor was approximately 80 m with radiometric coverage in four spectral bands from the visible green to the near-infrared (IR) wavelengths. Only the MSS sensor on Landsat 3 had a fifth band in the thermal-IR.
The Landsat platforms operate from a sun-synchronous, near-polar orbit imaging the same 185 km (115 miles) ground swath every 16 days (formerly 18 days on Landsats 1 through 3). Multispectral scanner (MSS) data were received directly from Landsats 4 and 5 by a network of 16 worldwide ground stations.
does not apply to imagery data
Are there legal restrictions on access or use of the data?
- Access_Constraints: none
- Use_Constraints: none
Data Manager
Spatial Data and Visualization Center
Box 4008 University Station
Laramie, Wyoming 82071
USA
307-766-2735 (voice)
n/a
The distributor shall not be held liable for improper or incorrect use of this data, based on the description of appropriate/inappropriate used described in this metadata document. The distributor makes no claims for the data's suitability for other purposes.
| Data format: | TIFF |
|---|---|
| Network links: |
ftp.sdvc.uwyo.edu or <http://www.sdvc.uwyo.edu/clearinghouse> |
No fees are required for downloading the data that is on-line. Some fees may be required to cover costs of tapes if data is required on tape media.
Margo Berendsen
Box 4008 University Station
Laramie, Wyoming 82071
USA
307-766-2751 (voice)
meh@uwyo.edu