PHOTOGRAMMETRY AS APPLIED BY FEDERAL HIGHWAY PROJECTS OFFICE REGION 9, U.S. BUREAU OF PUBLIC ROADS

THE AERIAL SURVEYS BRANCH OF THE US BUREAU OF PUBLIC ROADS BEGAN TRAINING LIMITED NUMBERS OF THE REGION 9 FEDERAL HIGHWAY PROJECT'S PERSONNEL IN AERIAL SURVEYS AND PHOTOGRAMMETRY IN 1950. EMPHASIS WAS PLACED ON THE EFFECTIVENESS OF AERIAL SURVEYS AND PHOTOGRAMMETRY IN RECONNAISSANCE SURVEYS AND IN PRELIMINARY SURVEY AND DESIGN. BETWEEN 1957 AND 1959 PERSONNEL WERE TRAINED IN OPERATING PRECISION STEREOSCOPIC INSTRUMENTS, EQUIPMENT WAS OBTAINED, AND PRELIMINARY SURVEYS WERE MADE FOR HIGHWAY LOCATION PURPOSES BY AERIAL SURVEY INSTEAD OF GROUND SURVEY METHODS. THE AERIAL PHOTOGRAPHY SPECIFICATIONS ARE PATTERNED AFTER THE "REFERENCE GUIDE OUTLINE SPECIFICATIONS FOR AERIAL SURVEYS AND MAPPING BY PHOTOGRAMMETRIC METHODS FOR HIGHWAYS, 1958," GROUND SURVEY CONTROL WORK IS PERFORMED BY TRAINED US BUREAU OF PUBLIC ROADS PERSONNEL. THE STATE PLANE COORDINATES ARE ADJUSTED FOR EACH SURVEY PROJECT TO A DATAM WHERE DIFFERENCES BETWEEN DISTANCES DETERMINED FROM PLANE COORDINATES ON THE MAPS AND DISTANCES MEASURED HORIZONTALLY ON THE GROUND WILL NOT BE LARGER THAN PERMISSABLE BY ACCURACIES REQUIRED IN THE BASIC CONTROL SURVEYS. THE CONTROL TRAVERSE IS MEASURED BY USE OF T-2 THEODOLITES, 12-FT. SUBTENSE BARS, AND ELECTRONIC MEASURING DEVICES. TRAVERSE AZIMUTHS, DISTANCES, AND PLANE COORDINATES ARE COMPUTED BY AN IBM PROGRAM WRITTEN SPECIFICALLY FOR THEODOLITE-SUBTENSE BAR MEASURED TRAVERSES. MAP MANUSCRIPTS ARE COMPLIED EITHER BY COMMERCIAL FIRMS UNDER NEGOTIATED CONTRACTS OR BY REGION 9 PERSONNEL AND EQUIPMENT. IN ADDITION TO USING AERIAL PHOTOGRAPHY FOR HIGHWAY LOCATION AND DESIGN, ENLARGED PHOTOGRAPHS AND SEMI-CONTROLLED PHOTOGRAPHIC MOSAICS ARE USED TO ADVANTAGE IN THE ACQUISITION OF RIGHT-OF-WAY AND CONDEMNATION HEARINGS. WITH APPROXIMATELY 400 MILES OF HIGHWAY SURVEYS COMPLETED BY AERIAL METHODS, REGION 9 PERSONNEL ARE AWARE OF THE NUMEROUS BENEFITS OBTAINABLE FROM AERIAL SURVEYS INCLUDING REDUCED SURVEY COSTS, MORE COMPLETE AND ACCURATE DATA FOR DESIGN, AND ACHIEVEMENT OF BETTER HIGHWAY LOCATIONS FOR THE CONSTRUCTION FUNDS AVAILABLE.

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  • Accession Number: 00202840
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Sep 21 1970 12:00AM