Files for HSG percent data
Data set reference code -- 1996-0090
To accommodate users with a variety of GIS software, the data giving the
percent of a mapunit or grid cell in each of the four hydrologic soil
groups (A, B, C, and D) or covered by water (W) are available in several
different formats. The files needed by each of the types of user below
are described separately.
NOTE: Most of these files have been compressed using
the GNU gzip program, as indicated by the .gz file
extension. Users who do not have access to the gunzip
decompression program can request that files be uncompressed prior to
transfer via ftp. In some cases, however, the uncompressed file may be
very much larger than the compressed version, greatly increasing file
The orginal STATSGO mapunits for the 48 states have been merged into a
single Arc/Info polygon (vector) coverage. The HSG percents for each
mapunit are given by auxilliary INFO tables, which may be RELATEd to the
mapunit coverage using "MUID" as the relate item. The needed files are
The mapunits have been gridded at 30-arcsec cell size. The value attribute
table (VAT) for the Arc/Info grid listed below contains the mapunit
indentifier, MUID, the mapunit serial number, MUSERIAL, and the
probabilities, in percent, that a given grid cell in is each of the
hydrologic soil groups. The Arc/Info grid may be downloaded as a single
mu_poly.e00.gz (101 Mbyte, uncompresses to 269 Mbyte)
- Mapunit polygon coverage in Arc/Info EXPORT format.
mu_hsgpct.e00.gz (111 kbyte, uncompresses to 384 kbyte)
- INFO table giving percent of each mapunit in each hydrologic soil
group, in Arc/Info EXPORT format.
Warning -- The uncompressed version of the grid
file below is very much larger than the compressed version.
The 30-arcsec gridded data are also available as a three-dimensional array of
8-bit binary values, in band-sequential (BSQ) form. The third dimension
consists of 5 "layers", corresponding to the percent probabilities that
each grid cell is in HSG A, B, C, D, or W (water), respectively. Values
for all rows and columns of the first layer are given first, followed by
all data for the second layer, and so on. Within each layer, the data
are organized by horizontal rows, with the top (northern-most) row
first, and the data for each row starting at the left (western) end of
hsgpctgrid.e00.gz (10 Mbyte, uncompresses to 191 Mbyte)
- 30-arcsec grid of mapunits, including VAT, in Arc/Info format.
The array contains 5 layers each containing 2984 rows of 6936 values.
Code for reading the binary array is available in Fortran 77
The data are contained in a single file:
Warning -- The uncompressed version of the BSQ file
below is very much larger than the compressed version.
The filesystems containing the datasets are cross-mounted on the local
ESSC computer network. Local Arc/Info users may find it more convenient
to copy necessary files directly to their own workspaces using the
Arc/Info COPY and COPYINFO commands. The needed directories and files
(under directory $DSREF/1996-0090/) are
hsgpct.bsq.gz (7.5 Mbyte, uncompresses to 103 Mbyte)
- Three dimensional array of percent probabilities that each grid cell
is in each of the four hydrologic soil groups or is water.
- Arc/Info grid representation of mapunits; the HSG percent
information from table MU_HSGPCT is included in the VAT for this
- Arc/Info coverage containing polygon version of mapunit boundaries.
- INFO table giving percent of each mapunit's area in each of the four
hydrologic soil groups plus water (W).
Last change: 2006 Apr 14,
R. A. White / firstname.lastname@example.org