By Ronald B. Zelt and Jennifer B. Sharpe
ABSTRACT:
The Multi-Resolution Land Characterization (MRLC) consortium, made up of
representatives from five Federal programs, cooperated to select and purchase
Landsat-5 Thematic Mapper (TM) image data for the conterminous U.S. In
addition, the MRLC consortium cooperated with the U.S. Geological Survey
(USGS) EROS Data Center to develop and implement a procedure for
preprocessing, georeferencing, and spectrally analyzing these data. Landsat
TM data for the Path-31, Row-31 Quadrilateral (roughly, lat 40°47' to 42°15'N,
long 99°20' to 102°07'W.) were collected on July 14, 1991, and processed
according to MRLC protocols using an unsupervised multi-variate cluster
analysis to produce an image data set consisting of 240 unlabeled categories
or clusters. The clusters were assigned to land-cover classes within a
heirarchical classification system developed for a USGS National Water-Quality
Assessment Program (NAWQA) study of the Central Nebraska Basins. The Central
Nebraska Basins include the area drained by the Platte River between the
confluence of the North Platte and South Platte Rivers and the mouth of the
Platte River. The report contains interpreted image data for the 23,500-km²
part of the Path-31, Row-31 Quadrilateral that is within the Central Nebraska
Basins study unit. The data set includes a single-band, 16-bit raster array
in which each grid cell (pixel) contains a coded value that incorporates both
the original cluster number and a stratum number corresponding to one of the
environmental settings of Central Nebraska that were used to spatially
stratify the clusters. Data encoding the assigned land-cover class for each
grid-cell code are included in tabular form.
About 91 percent of the data set was interpreted as grass covered, and about 7
percent as cropland and pasture. Mixed vegetation (about 1 percent) and other
minor land-cover classes account for the remainder of the data set. The
classification accuracy of the data set has not been quantitatively assessed,
but comparisons with some available land-cover observations from 1993-94 were
tabulated.
DESCRIPTORS: Nebraska, Land Cover
CITATION:
Zelt, R.B., and Sharpe, J.B., 2000, Land Cover Data for Central Nebraska, 1991,
Classified from Landsat-5 Thematic Mapper Imagery -- Path-31, Row-31 Quadrilateral:
U.S. Geological Survey Open-File Report 96-323, compact disc.
THIS REPORT IS "IN PRESS" CURRENTLY; AFTER ITS PUBLICATION AND RELEASE,
THE FOLLOWING CONTACTS WILL APPLY.
For additional information Copies of the report can be
write to: purchased from:
District Chief U.S. Geological Survey
U.S. Geological Survey, WRD Branch of Information Services
406 Federal Building Box 25286
100 Centennial Mall, North Denver Federal Center
Lincoln, Nebraska 68508 Denver, CO 80225-0286