APPENDIX A: ARCVIEW GIS 3.1
ArcView stores data in a format called a shapefile (.SHP). The shapefiles are defined, for
our purposes, as point, line, or polygon shapes. There is no text or annotation data type in a
shapefile. Geometry is stored in a .SHP file, a spatial index is built in a .SHX file, and
database attributes associated with the shapes are stored in a dBase file (.DBF). AutoCAD
data can be read directly using the ArcView CAD Reader extension. Conversion is facili-
tated via the Convert To Shapefile option in ArcView. Custom conversion tools can be
written in ArcView with the Avenue programming language. See the ArcView help docu-
ment for object mapping.
ArcView has two additional features that make it useful for the conversion process. First,
any AutoCAD polyline that is closed, or any open polyline whose beginning and ending
points are identical, is interpreted as a polygon shape. Second, attributes of blocks are auto-
matically associated with the block insertion point, which defines a point shape, by
denormalizing the data in the associated table.
A future version of this document will provide more information on using ArcView GIS
and CAD data.