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This feature class is maintained to keep construction, mapping and all city services in and adjacent to the city on the same vertical datum. Thus minimizing mistakes or conflicts in construction or maintenance of the infrastructure of the city. This feature class represents the cities vertical control network which was started approximatley in 1971. The oringinal bench mark used to start the network was a NGS (Nationa Geodetic Survey) monument located in the northwest part of the city (Stapleton Airport/Peoria and Smith). Level loops and runs were added and extended as the city grew. Which also incorporated more NGS monuments. The datum used when the program started was NGVD (National Geodetic Vertical Datum) of 1929 . In June of 2006 the city converted from NGVD 1929 to NAVD (North American Vertical Datum) of 1988 using Corpscon 6.0.1 and the Geoid 2003. This network has been successful and should be maintained until a improved alternative can be utilized. |