In implementing a comprehensive GIS, Richland County has begun collecting thematic data for several departments and applications using global positioning system (GPS) technologies. For GPS data collection projects within the County, a set of minimum standards is being followed to assure consistency in resulting products. This document is a summary of GPS standards used by County personnel.
It should be noted that Richland County has adopted the GPS standards developed by the North Carolina Geographic Information Coordinating Council. There is no similar coordinating body or set of approved standards for South Carolina. For a complete review of the technology and standard elements, please refer to the full text of the NC GPS standard.
I. Overview
This document establishes the minimum GPS standards to be used by County personnel involved in mapping activities as well as individuals and groups submitting digital data to Richland County, South Carolina. Please refer to the NC GPS Standard document for field method guidelines as well as specific requirements for accuracy and precision. The following addresses only ground collected data and does not apply to aerial GPS procedures. The standards apply to current technology and are subject to revision as GPS equipment develops.
II. Standards
GPS Receiver Standards
- The GPS receiver must be of mapping-grade or better.
- The GPS receiver must produce and store data in a format compatible with the base station data used to perform the differential corrections or have the capability to receive real-time corrections from the base station.
GPS Data Collection Standards
Static Collection - We suggest standing at a collection location for 5-10 seconds to evaluate the quality of signal (PDOP and number of satellites) before gathering points.
Kinematic Mode - Although kinematic collection will acquire points at lower positional accuracy, we accept line features collected with this method provided points are collected frequently.
Elevation Mask - The elevation mask should be set to 10 degrees or higher.
Horizontal Datum - NAD 83 (North American Datum 1983)
Spheroid - GRS 1980
Positional Dilution of Precision (PDOP) - Set your receiver to collect points only when PDOP is less than 6.
Satellites - Set your receiver to collect points only when it has signals from 4 or more satellites.
Units - Units will be in International Foot.
Coordinate System - Data submitted to Richland County will be in South Carolina State Plane coordinate system.
Elevation Mode - Use the Height Above Ellipsoid (HAE) as the elevation mode.
Exchange Format - ESRI Shapefile (one file per theme).
Metadata - .TXT file including collectors name, date collected, theme description, and receiver type.