SDTS: Spatial Data Transfer Standard

• SDTS is a new USGS format that supposed to incorporate and obsolete older formats, including elevation data (DEM) and vector data (TIGER & DLG)
• main page: SDTS Home Page
• it is a truly ugly, awful mess of a format
• for example, a DLG file which used to be a single file, e.g. "hilo-mt.dlg", is now divided into 21 files with the following cryptic names:

  MT01AHDR.DDF MT01AMTF.DDF MT01CATD.DDF MT01CATS.DDF MT01CATX.DDF MT01DDSH.DDF MT01DQAA.DDF

  MT01DQCG.DDF MT01DQHL.DDF MT01DQLC.DDF MT01DQPA.DDF MT01FF01.DDF MT01IDEN.DDF MT01IREF.DDF

  MT01LE01.DDF MT01NA01.DDF MT01NO01.DDF MT01NP01.DDF MT01PC01.DDF MT01STAT.DDF MT01XREF.DDF

• sadly, USGS now uses SDTS for all their vector and elevation data that is freely available online
• you can still get the data in the older and simpler formats, but those cost money

Developer Info

• GDAL also supports SDTS and i've found it to be most portable and easiest to use
  • even easier is to use GDAL indirectly by using vtdata
• SDTS++ is a C++ toolkit that developers can use to write applications that can read and write SDTS datasets
• USGS's (historical) viewer program DLGV32 read SDTS, and full source code was available
  • strangely, the version of SDTS++ included in the DLGV32 source code was significantly different from the SDTS++ library above, although they were both maintained by the USGS