GROUND WATER - CalComp computer graphic techniques applicable to WRD aquifer simulation model analysis.


             UNITED STATES DEPARTMENT OF THE INTERIOR
                         GEOLOGICAL SURVEY
                      RESTON, VIRGINIA  22092

                                                      GW Branch

                                              November 19, 1976
                                                 Code 4351 5016

GROUND WATER BRANCH TECHNICAL MEMORANDUM NO. 77.01

Subject:  GROUND WATER - CalComp computer graphic techniques
                         applicable to WRD aquifer simulation
                         model analysis.

Two reports that provide information on computer graphics useful
to anyone using WRD's aquifer simulation modefls have come to
our attention, and copies are attached.

The report by Cosner and Horwich describes a computer program that
is designed specifically for the Pinder 1970 aquifer simulation
model and the Trescott 1972 aquifer simulation model, but it can
be adapted to other similar models.  The program provides as
output the data cards needed for input to the CalComp general-
purpose contouring program (GPCP) so that the computed potentiometric
or drawdown data for the model grid can be produced in contour-map
form by a CalComp plotter.

The program described in the report by Wells, Faust, and Mercer
prepares a CalComp plotter tape useful for drawing cross-sections
from gridded map data or for preparing areal contour maps.

Examples given of uses for cross-sectional computer plots include:
(1) cross sections showing variations in thickness of various
hydrologic units, and (2) computed water-level profiles at selected
times.  An example given of use for an areal computer plot is a
structural contour map on the top of a selected hydrologic unit.

Please bring these reports to the attention of ground-water
specialists concerned with aquifer modeling studies.



                              (s) Charles A. Appel
                              Ground Water Branch
                              Water Resources Division

Enclosures:

     (1) "Grid-coordinate generation program," by Oliver J. Cosner
          and Esther Horwich, U.S. Geol. Survey open-file rept.,
          1974.

     (2) "A cross-section plotting program (CSPP) for gridded
         (Map) data," by Richard B. Wells, Charles R. Faust, and
         James W. Mercer, U.S. Geol. Survey open-file rept.
         76-689, 1976.

WRD Distribution: A, B (Limited), FO-L, SL (Subdistrict Offices),
S (w/o attach.)