Many of these consist of data from one of the previous sources that has been processed in some way or had supplementary information added. None of the government-produced map series contain complete coverage of the hypsography of the state, so we are currently looking at alternatives, such as purchasing or producing contours created from DEMs . We also plan to add DRGs where appropriate. One of the principal factors in the choice of data sources is cost. The data from the federal government is available at a very low cost, usually not much more than the cost of the media and the personnel time involved in its reproduction.
Commercial data is much more expensive.
This is a shaded relief map of the Texas panhandle, over which Dan has plotted both county outlines and the areas of archeological surveys performed to date. The locations of these archeological surveys were digitized from maps on file in the Texas Historical Commission's Division of Antiquities Protection. Click on the small image below to see a larger version of the map. Another shaded relief map, this time plotted with 47,310 archeological sites recorded in Texas. These site locations were digitized from maps filed at the Texas Archeological Research Laboratory in Austin, Texas, the official state repository for archeological data, maps, records, and artifact collections.