As part of a unique pilot project in Geary and Saline counties in Kansas, GPS was used to assess the accuracy of existing digital mapping sources for Western Resources, a public utility company. Western Resources was about to embark on a project to build a GIS database of their electric power and natural gas distribution systems. The utility needed to determine if they could use existing digital mapping sources to develop a digital land base for their GIS or if they would have to fund all new mapping. The project was a joint effort between the Civil Engineering Technology section at Kansas State University-Salina in Salina, Kansas; Western Resources, Inc., Topeka, Kansas; M.J. Harden Associates, Kansas City, Missouri; and the Kansas Electric Utility Research Program (KEURP), Topeka, Kansas. In this project Western Resources, Inc., contracted with M.J. Harden Associates to develop a digital road centerline file (land base) of all city and county roads in Saline and Geary counties in Kansas. M.J. Harden used existing digital mapping sources to create the digital land base. The existing mapping sources were county engineering road and bridge maps, county reappraisal maps, 7.5' U.S. Geological Survey quadrangle maps, U.S. Census Bureau TIGER/Line files, and the Kansas Cartographic Database (KCD), a section corner database developed by the Kansas Geological Survey. M.J. Harden also created smart street centerline files for the urban area in Saline County using new photography controlled to the KCD for comparison. From the digital land base for each county, thirty road intersections were selected to be studied, fifteen in an urban area and fifteen dispersed throughout the county. Coordinates for the intersections were determined from the digital land base. GPS surveys of those same intersections were then conducted in the field. The digital land base coordinates for the intersections were then compared to the GPS coordinates to determine the accuracy and consistency of the land base files. Verification of the digital land base files with GPS technology provided an efficient means of evaluating the accuracy attained in the land base files versus the cost incurred for their development. The Saline County project yielded higher accuracies overall but the expense of the smart street centerline files drove the project cost higher. The added accuracy did not provide a large enough variance to justify the additional cost. The Geary County project, using only existing mapping sources, provided reasonable accuracies for a reasonable cost and would support a wide range of utility applications. All GPS field work and data reduction was accomplished by civil, surveying, and GIS students and faculty of the Civil Engineering Technology section of KSU-Salina, College of Technology with assistance from Mr. Jim Tyler of Western Resources, Inc. The students gained valuable real-world experience through their participation in this project. KEURP assisted with project funding and coordination.
As a part of a unique pilot project in Osage County, Kansas, GPS was used to assess the accuracy of existing 1991 digital orthophoto files for the whole County. In addition GPS was used to check the accuracy of the U.S. Geological Survey (USGS) Public Land Survey System (PLSS) for Osage County. The project was a joint effort between the Civil Engineering Technology section at Kansas State University-Salina in Salina, Kansas; the Natural Resources Conservation Service (formerly Soil Conservation Service) state office in Salina, Kansas; the Kansas Department of Revenue (Property Valuation Division), Topeka, Kansas; and the U.S. Geological Survey in Menlo Park, California. The goal of the first part of the project was to assess the accuracy and usability of the one meter resolution USGS digital orthophoto files for resource management and appraisal applications on a County-wide basis. Photo ID points were selected from the digital orthophoto files using a workstation running GRASS GIS software, and a coordinate was determined from the database for each point. That exact location was then visited with GPS in the field and a GPS ground coordinate was determined for the same point. The two coordinates were then compared to determine the accuracy and consistency of the digital orthophoto files throughout the County. The goal of the second part of the project was to ascertain the usability of the USGS PLSS database as a section line overlay for the one meter resolution digital orthophoto files. To accomplish the goal, coordinates were selected from the PLSS database for several section corners across the County that were known to have been recovered and easily accessible. Those section corners were then visited with GPS in the field and GPS ground coordinates were determined. The database coordinate and GPS coordinate were then compared to assess the accuracy and usability of the PLSS database. All GPS field work and data reduction was accomplished by civil, surveying, and GIS students and faculty of the Civil Engineering Technology section of KSU-Salina, College of Technology with assistance from the National Resource Conservation Service staff in Salina. The students gained valuable real-world experience through their participation in this project. The quality of the digital ortho files and PLSS database proved to be adequate for the applications tested. GPS proved to be a fast, reliable method of registering the digital orthophoto files and the PLSS database to the true ground locations.