Establishment of Map Renewal Technique for Local Government by Using Real Time Gis

Much local government has been utilizing a large-scale digital map using Geographic Information System (GIS). However, the maintenance and renewal of a map database need much labor and time. Moreover, the updating method of a map has not been established yet and there have been almost no successful examples. The purpose of the study is to establish a method of updating the large-scale map for local government using Real-Time GIS. The Real-Time GIS is a technique for updating a digital map instantly using the Real-Time Kinematic Global Positioning System (RTK-GPS) and mobile phones.Absolute position of a GPS is extremely precise, and the ellipsoid of Japanese is Geodetic Datum 2000 (JGD2000) of GRS-80. However, most of the digital maps of local government are still Tokyo Datum of an old geodetic system. To match two kinds of data having different geodetic systems, it is necessary to transform coordinates. Several methods were used for this problem. This study used TKY2JGD and Affine Transformation. In this paper, parameters which were calculated by Affine Transformation were named “High-Accuracy Regional Parameter (HARP).” As a result, parameters using TKY2JGD could not be applied to a large-scale map. Standard deviation of Affine Transformation had only 3cm errors. These results showed that HARP can transform Tokyo Datum to JGD2000. The paper suggested that Real Time GIS and HARP will help to revise the map of local government.