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 transfer time.

Arc/Info polygon file users

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
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.

Arc/Info grid file users

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 file:

Warning -- The uncompressed version of the grid file below is very much larger than the compressed version.

hsgpctgrid.e00.gz (10 Mbyte, uncompresses to 191 Mbyte)
30-arcsec grid of mapunits, including VAT, in Arc/Info format.

Other users of gridded data

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 the row.

The array contains 5 layers each containing 2984 rows of 6936 values. Code for reading the binary array is available in Fortran 77 and C.

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.

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.

Local users on the ESSC network

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
hsgpctgrid
Arc/Info grid representation of mapunits; the HSG percent information from table MU_HSGPCT is included in the VAT for this grid.
../mapunits/mu_poly
Arc/Info coverage containing polygon version of mapunit boundaries.
info!MU_HSGPCT
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 / raw@essc.psu.edu