How accurate is the elevation data in the GEONOMA Database? How was it measured?
The elevation data in GEONOMA is not official. Only the geographic name and locative attributes are official. All other attribute data are for enhancement only. In recording elevation data, if the elevation of a feature was actually published on the topographic map, it meant that the elevation data represented an actual, precisely surveyed point, and there was often a benchmark or triangle at the location on the map, and also for these there is actually a benchmark seal physically located and anchored into the ground at the site. If there was no surveyed point, then for use in GEONOMA, the elevation was determined by interpolation of contour lines. These lines are the brown lines on topographic maps that are drawn to connect points of equal elevation thereby providing a general schematic of landforms or the “lay of the land.” The elevation for features classified as summit (all uplifted features), is recorded at the highest point. For more information contact The Secretary.
