Highway engineering surveys by electronic tacheometry - cost and quality benefits for the engineer.

FOR THE PAST 60 YEARS, DATA FOR ROAD DESIGN HAVE BEEN COLLECTED BY SURVEYORS USING CROSS-SECTION METHODS. THESE METHODS WERE DICTATED BY THE RESTRICTED COMPUTING FACILITIES AVAILABLE FOR GRADE AND EARTHWORK VOLUME DETERMINATIONS. INTRODUCTION OF COMPUTERS AND DIGITAL GROUND MODEL PROGRAMS HAS REMOVED THIS CONSTRAINT. ANALYSES OF ALTERNATIVE SURVEY TECHNIQUES, AND IN PARTICULAR ELECTRONIC TACHEOMETRY, HAVE REVEALED THAT CROSS-SECTION METHODS ARE LESS EFFICIENT AND LESS ACCURATE AND SHOULD ONLY BE EMPLOYED UNDER SPECIFIC CIRCUMSTANCES. REFERENCE IS MADE TO THE INTER-RELATIONSHIP BETWEEN GROUND SURVEYS AND PHOTOGRAMMETRIC SURVEYS INCLUDING DIGITAL MAPPING TECHNIQUES. THE USE OF CO-ORDINATES IN DESIGN AND CONSTRUCTION AND FURTHER SIDE BENEFITS TO BE GAINED BY ELECTRONIC TACHEOMETRY ARE DISCUSSED. AREAS WHERE CROSS-SECTION METHODS WOULD STILL BE BENEFICIAL ARE CONSIDERED. (A). FOR THE COVERING ABSTRACT OF THE CONFERENCE PROCEEDINGS SEE IRRD ABSTRACT NO. 226354.