Regarding my request for assistance in reading and editing shape files directly, I received some web links and managed to find some others. To summarize, shape files are binary files. Specifications for the format are found in the following document that I referenced in my original question, and which appears to be the best reference: http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf This document assumes readers are familiar with manipulation of binary files. Information regarding manipulation of shape files is available at the following links: IEEE 8-byte floats are described at http://www.psc.edu/general/software/packages/ieee/ieee.html There is an open-source C API called shapelib. http://gdal.velocet.ca/projects/shapelib/index.html ESRI Support document pointing to above C API and other information: http://support.esri.com/search/KbDocument.asp?dbid=16068 Kenneth R. McVay Visual Basic project called ShapeIO that writes shape files 1/99: http://gis.esri.com/arcscripts/details.cfm?CFGRIDKEY=628102085 Kenneth R. McVay VB Shape IO (old version) 6/98: http://gis.esri.com/arcscripts/details.cfm?CFGRIDKEY=53817794 The key appears to be learning how to work with binary files. Thanks for the help. Andy -----Original Message----- Sent: Friday, October 19, 2001 9:19 AM Subject: GEN - Creating Shapefiles I have a copy of the 1998 white paper by ESRI entitled "ESRI Shapefile Technical Description" which defines the organization of contents of a shapefile. However, the document does not discuss the format of the file. What kind of file is it? It isn't a text file, and doesn't seem to be consistent with other formats I have tried. I want to read and edit shapefiles directly from my own program. Any suggestions? Thanks!