In this study, using world geodetic system transformation results, we tried to examine the types of errors and suggest directions for improvement through experiments and analysis of field application of cadastral surveying. The research results are as...
In this study, using world geodetic system transformation results, we tried to examine the types of errors and suggest directions for improvement through experiments and analysis of field application of cadastral surveying. The research results are as follows.
In order to empirically analyze the types of errors caused by cadastral surveying, an experimental study was conducted by selecting a research area. The study area was selected as an area with regular addition and subtraction results, an area with irregular addition and subtraction results, and a graphical area adjacent to digital area.
For detailed surveying of the experimental area, world geodetic system observation results of the supplementary control point of the study area were obtained. A total of 20 points were obtained for each region. World geodetic system observation results were obtained for supplementary control points in the study area, and detailed surveying was performed on parcels in the target area using these points. In order to compare and analyze the difference with the existing performance in carrying out detail surveying, parcels with a previous survey history were targeted.
Error types were analyzed by dividing them into reference points and parcels. As a result of the error type analysis of the reference point, it was found that the supplementary control point of 2 points exceeds 12.5 cm in the addition and subtraction result rule area. In addition and subtraction result, a total of 4 points were found to exceed the error tolerance in the irregular area. Based on the conversion performance of the reference point, the error section was divided into 10 cm, 20 cm, and 30 cm. As a result of analysis, 12 points within 10 cm, 4 points within 10 cm and 20 cm, and 2 points within 20 cm and 30 cm.
In this study, we analyzed the change in the location of the lot and the types of errors caused by the adjustment of the addition and subtraction result of the supplementary control point. The types were analyzed centered on the parcels that had been subjected to detail surveying. As a result of the analysis, it was found that the location of the local parcels changed as a whole due to the adjustment of the addition and subtraction result, resulting in cadastral non coincidences such as overlapping or blanking with adjacent parcels. In particular, in the case of areas where cadastral surveying results are separated, it was found that gaps or overlapping problems may occur in adjacent areas depending on how addition and subtraction results are adjusted. In the case of a graphical area adjacent to digital area, it was found that even when the addition and subtraction results were readjusted, a separation(overlapping and blanking) of about 3 to 4 cm occurred in each joint area.
As a result, there is no choice but to change the location, whether large or small, in drawings or in the field because the transformation of the local geodetic system and the world geodetic system cannot be completely changed without error. This positional change naturally causes cadastral non coincidence. Therefore, when applying the world geodetic system transformation map to the cadastral surveying site, it is necessary to closely monitor the occurrence of errors from the beginning and perform maintenance through re-surveying where necessary. If maintenance is difficult due to re-survey, it is judged that maintenance should be carried out in connection with the cadastral resurvey project. Based on the experimental analysis, the improvement direction of the application of cadastral surveying of world geodetic system transformation results was presented in technical and legal aspects.