POLYGON: An Interactive Program for Constructing and Editing the Geometries of Polygons Using a Color Graphics Terminal

摘要

This report is a user manual for the FORTRAN program POLYGON. POLYGON is designed to facilitate the construction and editing of the geometries of polygonal shapes using an Envision color-graphics terminal. The Open-File Report number 85-233-B (Chuchel, 1985) contains a listing of the FORTRAN source code for the POLYGON program. POLYGON features color-graphics, an interactive user dialogue, brief help messages, and ''zooming'' to selected portions of the terminal screen in order to edit and manipulate polygons using a graphics cursor or the Envision mouse. A quadruply linked tree is used within POLYGON to represent and store the information about the geometries of the polygons. These polygonal shapes may subsequently be used by independent modeling programs to represent three-dimensional shapes of gravitational or magnetic sources; for example, output from POLYGON is directly compatible with programs MAGPOLY or GRAVPOLY and PFGRAV3D or PFMAG3D. POLYGON is written in DEC (Digital Equipment Corporation) extended FORTRAN 77 and is presently operational on the USGS, Branch of Geophysics, VAX/VMS computer. The program is written to operate on the Envision 200 series of color graphics terminals by Envision Technology Incorporated. Suggestions are provided on converting the program to other types of color terminals. (ERA citation 11:001937)