APPLICATIONS OF PHOTOGRAMMETRY TO THE LOCATION AND DESIGN OF FREEWAYS IN CALIFORNIA

AERIAL PHOTOGRAPHS ARE USED IN PRACTICALLY ALL OF THE STAGES OF FREEWAY PLANNING AND DESIGN IN CALIFORNIA. AMONG THE USES MENTIONED FOR CONTACT PRINTS, ENLARGEMENTS, AND MOSAICS ARE PRELIMINARY LOCATION STUDIES, PROJECT REPORTS, PUBLIC MEETINGS, STUDY OF DESIGN DETAILS, DETERMINATION OF DRAINAGE AREAS, MATERIALS INVESTIGATIONS, AND RIGHT-OF-WAY APPRAISAL, NEGOTIATION AND CONDEMNATION. DATA ARE PRESENTED SHOWING THE EXTENT TO WHICH AERIAL PHOTOGRAPHS HAVE BEEN USED FOR ROUTE STUDIES IN A TYPICAL NORTHERN CALIFORNIA HIGHWAY DISTRICT. WHERE MORE SPECIFIC INFORMATION IS REQUIRED FOR ROUTE STUDIES, THE AERIAL PHOTOGRAPHS ARE SUPPLEMENTED BY TOPOGRAPHIC MAPS. IN AREAS WHERE THEY ARE AVAILABLE, U.S. GEOLOGICAL SURVEY QUADRANGEL MAPS WILL FREQUENTLY SUFFICE. IN OTHER CASES RECONNASISSANCE-TYPE MAPPING IS OBTAINED BY CONTRACT. AFTER THE GENERAL LOCATION OF THE FREEWAY IS DETERMINED PHOTOGRAMMETRIC MAPPING, USUALLY AT A SCALE OF 1 IN. =50 FT WITH 2-FT CONTOURS, IS OBTAINED FOR DETAILED DESIGN WORK. ACCURATE, ADEQUATELY MONUMENTED CONTROL SURVEYS FOR USE IN CONJUNCTION WITH THE TOPOGRAPHIC MAPPING ARE AN IMPORTANT FEATURE OF CALIFORNIA PRACTICE. SPECIFICATION REQUIREMENTS AND OTHER SCALES OF OF MAPPING FOR DESIGN USE ARE DISCUSSED. THE USE OF ELECTRONIC COMPUTERS FOR THE CALCULATION OF EARTHWORK QUANTITIES HAS LARGELY SUPERSEDED OTHER METHODS. TERRAIN AND ROADBED NOTES SIMILAR TO CONVENTIONAL SURVEY NOTES ARE PREPARED BY THE DESIGNER FOR MACHINE COMPUTATION. DATA FOR TERRAIN NOTES ARE OBTAINED FROM THE LARGE-SCALE PHOTOGRAMMETRIC MAPS. CHANGES IN LIEN OR GRADE CAN BE MADE BY DESIGNATING HORIZONTAL OR VERTICAL SHIFTS OF THE ROADBED NOTES. A FEW SAMPLE CROSS-SECTIONS FOR ILLUSTRATIVE PURPOSES ARE PLOTTED AS REQUIRED USUALLY AT A SMALL SCALE. PRELIMINARY QUANTITIES FORM AERIAL CONTOUR MAPS HAVE GENERALLY AGREED WITH FINAL QUANTITIES WITHIN LESS THAN 2 1/2 PERCENT. SUBSTANTIAL SAVINGS IN COST AND MANPOWER THROUGH THE USE OF PHOTOGRAMMETRIC MAPPING AND ELECTRONIC COMPUTERS ARE REPORTED. /AUTHOR/

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  • Accession Number: 00202758
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Jul 28 1994 12:00AM