HANDTC, a Fortran program to calculate innerzone terrain corrections

Abstract

FORTRAN program "Handtc" computes inner-zone terrain corrections for Hayford-Bowie zones C through F and Hammer zones D through H.The terrain corrections are based on the formula for the gravitational attraction of a vertical cylinder.The input file consists of four record types: a station record, a zone label record/ a compartment elevation record, and a blank record.The program generates two files: an output file and a print file.The output file lists the station name, total terrain correction, and the various zone terrain corrections in integer format."Hie print file lists the station name, station elevation, units, method, zone labels, compartment elevations, terrain corrections for each compartment, terrain correction for each zone, and the total terrain correction.The format of the print file is such that it can be quickly scanned and compared to the input file to check for errors in format, zone labels, compartment elevations, or anomalous terrain corrections.