Topic: The Development of SDTS Utilities in ARC/INFO for Spatial Data Distribution

E-Mail: mnegri@qvarsx.er.usgs.gov

FTP ftp://h2o.er.usgs.gov/pub/sdts_amls.tar.gz
(location of AML's with instructions)

Some features of the WRD's spatial data sets were not supported by the SDTS including the requirement for polygon topology and Albers Equal Area Projection. Two SDTS utilities (SDTSARC and ARCSDTS) were developed in ARC Macro Language (AML) to make conversion of SDTS data compatible with WRD projections and formats and easy for WRD spatial data users to use in their applications.

ARCSDTS checks an ARC/INFO data set for the proper map projection and topological structure and modifies it for export using the SDTSEXPORT command. ARCSDTS puts the modular SDTS files in a single, compressed "tar" file.

SDTSARC converts files created with ARCSDTS back to their original structure. It will work on "tar" file sets of SDTS files that were not created with ARCSDTS as well.

Problems reported to ESRI and SDTS Task Force:

• SDTSIMPORT supports single precision only. Double precision is necessary to accommodate high accuracy data.
• Only four map projections are supported. All WRD data are in Albers Equal Area projection.
• Polygon topology is required for the SDTS-TVP data.

These AML's along with instructions for loading and using them is available at WRD's FTP site located at: ftp://h2o.er.usgs.gov/pub/sdts_amls.tar.gz