+jeff35080 Posted January 7, 2004 Share Posted January 7, 2004 Can someone explain to me what the US Dept of Interior uses these types of disks for. I found several this past weekend and am kinda curious. Quote Link to comment
DaveD Posted January 7, 2004 Share Posted January 7, 2004 The U.S. Geological Survey (USGS), and agency in the Dept. of the Interior has the responsibility for producing our national topographic maps. They completed the monumental task of complete national mapping of the 1:24,000 scale map series (about 55,000 maps) in the early 1990's. USGS would often set survey monuments to help "control" the map. Maps are produced from aeronautical photos mosaiced together. In order to provide accurate location, orientation, scale and elevation to a flat map of a curved surface, it is required to have numerous points that can be identified on the photographs for which the coordinates/elevations are well known. The marks set by USGS were a vital part of this operation. In the days when mapping surveys were conducted primarily by line-of-site methods, these marks helped save money by helping to ensure a network that cartographers could rely on for mapping update procedures. With the rapid developments in surveying and mapping technology, especially GPS, USGS sees little need to setting new marks or maintaining the old networks. Unfortunately the data for tens of thousands of these marks set by USGS were never submitted to NGS for inclusion in the National Spatial Reference System. Due to major reductions in staff and the changing nature of mapping requirements, it is highly unlikely that USGS will ever automate these data. Quote Link to comment
+jeff35080 Posted January 7, 2004 Author Share Posted January 7, 2004 Thanks for the info Dave. Out of all the marks I have found I had never found a DOI mark until this past weekend when I found 2 of them. Cheers! Quote Link to comment
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