Notes on Public GIS Data
March 16, 2010
I have good information that Glade Top Trail, in the Ava ranger district of Mark Twain National Forest may be a good area to look for hog.
The PDF maps above provide the boundaries. I could potentially "trace" these to provide imprecise boundary vector data.
March 17, 2010
"Highly detailed maps, including quadrangle maps, can be purchased through the U.S. Geological Survey (USGS) or its retail partners. Visit their website or call 1-888-ASK-USGS."
Earth Explorer Digital Line Graphs, Large Scale (1:24,000) 7.5 min Quad 7.5-Min DLG Bound NATIVE = USGS Free Viewer: DLGVFree32
I spoke to someone at the USGS, and he was very helpful. He gave me a quick tutorial on how to use the Earth Explorer to search for the data I am looking for. He suggested I look for DLG (Digital Line Graphs) Boundary data. Large Scale was generated from the 1:24,000 topographical data, and is organized into the 7.5 minute quads. It helps if I know the names of these. I should download the NATIVE format, which is what the USGS uses, and which is understood by most GIS software.
I found that boundary data is not available at the Large Scale 1:24,000 level. I also found that the boundary data for MTNF at the 1:100,000 level only includes the outer boundaries. In short, the USGS does not appear to have the level of detail that I am looking for. It probably doesn't exist, except on paper.
The hypsographic (elevation contour) data at the 1:24,000 level is quite exhaustive, however. If I end up producing my own map data, I'm sure I will want to include this. At the 1:100,000 level, there appears to be data for rivers and bodies of water, roads, etc. I will want to incorporate all of this.
DLGV32 is a viewer, available in a form that is free, which I can use to view the data I have downloaded and verify its suitability.