Comparative study of georefference technique using photogrammtric and geographical information system softwares

Abstract

In photogrammetry, georeference is a process to determine ground coordinate based on measurement of photo coordinate. In digital photogrammetry, georeference process can be carried out using many softwares which are widely available. Georeference is important in photogrammetry. There are many techniques of georeference such as rectification and orthorectification. The accuracy of georeference is very critical because it depends on the capability of the software to produce good accuracy. Today there are many software available for digital photogrammetry but each software may use different algorithm. The aim of this study is to make comparison of accuracy between three softwares ERDAS IMAGINE 2011, ArcGIS 9.3 and Global Mapper 13 using different georeference techniques. In this study, four aerial photos, acquired from Department of Survey and Mapping Malaysia and 11 GCPs and 21 CPs were established using rapid static technique of Global Positioning System (GPS) and secondary data were used to perform georeference process. Georeference process was performed using the three softwares and these comparison was made based on Root Mean Square Error (RMSE). Also digitizing is carried out from the rectified and orthorectified photos in the three softwares. The distance measurements was also compared with distance measured on the ground. The RMSE based on point measurement, distance measurement and other factors such as time taken for processing was compared for the three softwares. In this study the results showed that orthorectification technique in ERDAS IMAGINE 2011 software produces better accuracy (±0.333m) compared to rectification technique in ArcGIS 9.3 (±0.879m) and Global Mapper 13 (±1.367m). As conclusion, Global Mapper13 and ArcGIS9.3 can generate rectified photo with reasonable accuracy but both softwares could not produced block triangulation and orthophoto. However, ArcGIS9.3 and Global Mapper13 softwares are much more user friendly compared to ERDAS IMAGINE 2011 software.