PROCESSING OF FIELD SURVEY DATA USING ANALYTICAL PHOTOGRAMMETRIC TECHNIQ UE

Abstract

Establishment of control points is a necessary step for preparing a map required in any engineering project. This is mainly done by conventional surveying or photogrammetry method. A comparison of these two methods in terms of precision, reliability, and cost shows that conventional surveying method is superior to photogrammetric technique. However, having vast potential of analytical photogrammetry for data reduction purposes, one is tempted to think of a combination of conventional surveying and analytical photogrammetric techniques which may provide better results rather than using them individually. One of the combination approaches was developed by Abdel-Aziz in 1979 wherein field survey data was processed using analytical photogrammetric reduction technique. In this method from theodolite measurements a fictitious photograph was generated, then applying coplanarity condition to the image coordinates of the fictitious photograph, ground coordinates of target points were obtained. In this dissertation an attempt has been made to investigate Abdel-Aziz's combined approach by comparing it with conventional surveying method. A computer program was prepared for the Abdel-Aziz's combined method and was tested on the data given by Abdel-Aziz. The computed height of the target points obtained from Abdel-Aziz combined approach did not match with that of given by Abdel-Aziz in his paper and therefore it was decided to reinvestigate and modify the method in the light of the above . results and also to modify it for a general theodolite base orientation which is Abdel-Aziz's suggested approach should be parallel to the face of the object, and to check the accuracy of the modified combined approach with that of conventional surveying. The modified combined approach was first checked for a simulation case, and when some encouraging results were obtained, then the modified combined approach was compared with conventional surveying method for a practical case. Results obtained shows that the modified combined approach gives better accuracy and has more reliability than surveying methOd and is applicable for any theodolite base orientation. (