Comparison of UAV Mapping of Settlement Scheme with PIDs/RIMs A Case study of Nyansiongo Settlement Scheme

Abstract

The study discusses examining the Parcels digitized from RIMs compared with the Parcels derived from the UAV Ortho-rectified images of the same area. Nyansiongo Settlement Scheme has been used as an example to determine the possible variations that exist between the two different techniques of the survey. It comprises of the acquiring of the RIMs maps from the Survey Office, scanning them to obtain the maps in digital format. The scanned RIM is then imported in the ArcGIS environment to be geo-referenced and then digitized. The parcels that were obtained were then used to be compared with UAV-derived imagery of the same area. The UAV derive Imagery was acquired by first, having reconnaissance in the field that is the Nyansiongo settlement scheme. In the establishment of control points that were to be used by UAV Technology, the Real-Time Kinematic GPS was used. RTK GPS base was used to establish the control points together with the base CORS-Network at Kisii town station RTCM (Radio Technical Commission of Maritime). The flight planning was done with the PIX4D software for the area of study. Then the UAV that is the Phantom UAV was used to take the aerial survey to capture the imagery of the 5cm resolution of the part of the Settlement scheme that was used in the study. The flight altitude or height was 110m and a sufficient overlap of 75% side overlap and 80% forward overlap. The images that were obtained from the UAV were post-processed using UASMaster software that is automated to generate the Ortho-rectified image of the study area. The Ortho-rectified image from the UAV was digitized in ArcGIS software by overlaying it with the scanned and Geo-referenced RIM to determine the boundary line of the parcels. The UAV digitized parcels were referred to as UAV derived parcels while those from RIM were referred to as Digitized RIM parcels. A shift was identified when the two sets of data were overlaid. That is the UAV derived parcels with that of RIM digitized parcels. In comparison between the UAV derive parcels with that of RIM digitized parcels a shift in terms of perimeter and area were measured. The shift in the perimeter is 558.31 Meters while as the shift in the area of the same section was 6,080.82Square Meters. This was as a result of the level of technology involved in surveying the same settlement scheme is different. The traditional method used in surveying the settlement scheme involved the use viii of aerial photography methods; boundaries are marked on the enlarged photographs. Through Photogrammetric processes, RIMs are generated. The UAV technology is of high accuracy and the imagery obtained from it was 5cm spatial resolution as compared with the conventional methods that were used to generate the RIMs.