Comparative Analysis of DTM Results with Hydro Enforcement LiDAR Data Method and Interferometric Synthetic Aperture Radar (InSAR) from Radar Satellite Imagery (Case Study of Kebumen Regency)

Abstract

Data containing information on the terrain elevation model is necessary for several uses related to human activities, such as development planning, spatial planning, disaster modeling, disaster mitigation planning, land productivity estimation, etc. Information about the ground elevation can be presented in a 3-dimensional topographical model such as Digital Terrain Model (DTM). There are several technologies used to form DTM data, including by using LiDAR and radar satellites (Sentinel-1). The hydro enforcement method is used to process DTM with LiDAR data by modifying the elevation value of LiDAR data in water areas during data processing. The height of this feature is modified digitally to achieve hydrological connectivity. This method aims to produce a DTM according to the principles of hydro enforcement and hydro flatten. While for processing DTM radar data, the InSAR method is used. InSAR is a remote sensing technique to extract three-dimensional information from the earth’s surface with the phase of radar waves. Additional data of morphological information and break lines were added to provide more representative information on the actual situation. The result of this research is the value of vertical geometry accuracy (LE90) of DTM to RBI data with a scale of 1:25,000. In this research, 5 kinds of DTM have been successfully formed with LE90 vertical accuracy values are as follows: LiDAR DTM with LE90 of 4.614 m; InSAR DTM with LE90 of 9.583 m; InSAR breakline with LE90 of 9.433 m; InSAR RBI assimilation with LE90 of 2.532 m; and InSAR DTM-LiDAR assimilation with LE90 of 4.077 m. DTM with the highest accuracy based on Topographic Map (RBI) 1:25,000 is InSAR DTM RBI assimilation and the lowest accuracy is DTM InSAR without breakline and assimilation data.