1/1/2024 0 Comments Digital raster graphic drg![]() And of course you'll want to keep in mind how old the map that DRG is a scan of is - springs may have dried up since it was last updated. A Digital Raster Graphic (DRG) is a digital image (scanned version) of the USGS topographic map. Often in those types of mapping software (National Geographic Topo!, whatever Delorme's is called, etc) they had somebody go in and digitize those named points on the map to create searchable data for the software.ĭepending on how big an area you're looking at, digitizing your own layer might be fastest. For example Garmin's Topo data has points for at least some springs if you have it and can extract it - I believe some of their data is derived from quad sheets, but don't quote me on that. ![]() Otherwise you're looking at commercial aquisition. Local/state sources might also have the data you're looking for in a consumable GIS format. ![]() The GNIS (named points layers) may have some in there as well. The vintage of the original input data varies considerably. Springs/seeps that appear on the DRG may or may not be in the NHD data and vice versa - it depends on how old/when the data on both sides was verified. USGS digital raster graphics (drg) are color image versions of the USGS topographical series maps. You can grab the point layer, which has stream guages, dams, and 'other' (including seeps/springs) from the National Map (look for the Click Here. ![]() The National Hydrography Dataset is where you'd start looking. Some of the data that goes into the quad sheets is available as vector data. DRG : Digital Raster Graphic data Publication Information Publication Place Reston, Va. The short answer is no - the question is basically about automated feature extraction from imagery. ![]()
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