I have been creating lots of site vicinity and geologic maps for geotechnical investigation using ArcGIS lately. Working around the Dallas-Fort Worth metroplex, I used to rely on GIS data provided by the North Central Texas Council of Governments (NCTCOG) – an awesome resource for this area. But once you leave the counties that are part of NCTCOG, you have to either use ESRI data or find another source, e.g. TNRIS (Texas Natural Resources Information System). I’ve been especially pleased with the digital version of the Geologic Atlas of Texas, or GAT, (supplied by TNRIS).
One problem I’ve run into is that the ESRI data that comes with ArcGIS doesn’t seem to include many of the smaller bodies of water in Texas, e.g. most smaller lakes. However, the GAT files have all these maps in the. I’ve been extracting the lakes from the geology shapefiles and adding them as a new layer to my vicinity maps with missing lakes. However, I find that bodies of water mapped by GAT overlap very inconveniently with roads and other features in the ESRI data ! What to do ? Turns out that the US Geological Survey provides National Hydrography Dataset (NHD) information. Here, you select a geographic area and the hydrologic features you’re interested in, e.g. water bodies, and have the information emailed to you as shapefiles. On my most recent map, the outline of the lake I needed fits in perfectly with the highways and streets shapefiles from ESRI.