RELATIONSHIP OF TOPOGRAPHIC RELIEF, FLIGHT, HEIGHT, AND AND MINIMUM AND MAXIMUM OVERLAP

THE EFFECTS OF TOPOGRAPHIC RELIEF ON OVERLAP IN AERIAL STEREOSCOPIC PHOTOGRAPHY BECOME ACUTE WHEN FLIGHT HEIGHT MUST BE SUFFICIENTLY LOW FOR TAKING AERIAL PHOTOGRAPHS SUITABLE FOR LARGE SCALE MAPPING BY PHOTOGRAMMETRIC METHODS FOR HIGHWAYS. WHILE THESE SAME EFFECTS ARE PRESENT IN SMALL SCALE PHOTOGRAPHY USED TO COMPILE SMALL SCALE MAPS, THEIR CONSEQUENCES ARE NOT ACUTE BECAUSE THE LARGE FLIGHT HEIGHT PERMITS A GREATER RELIEF HEIGHT. FOR THE DOUBLE PROJECTION PHOTOGRAMMETRIC INSTRUMENTS COMMONLY USED, THE RATIO OF RELIEF HEIGHT TO FLIGHT HEIGHT (H/H) VARIES FROM 0.21 TO 0.36. PRINCIPLES GOVERNING THE DESIGN OF ENDLAP (OVERLAP IN LINE OF FLIGHT) AND SIDELAP (OVERLAP OF ONE STRIP OF PHOTOGRAPHS ON ANOTHER) ARE PRESENTED. CONSIDERATIONS THAT MUST BE MADE WHEN DETERMINING THE MINIMUM FLIGHT HEIGHT THAT CAN BE UTILIZED ACCORDING TO THE RELIEF HEIGHT EXISTING IN THE AREA TO BE PHOTOGRAPHED AND MAPPED AT LARGE SCALE WITH SMALL CONTOUR INTERVAL ARE OUTLINED, AND THEIR EFFECTS ON THE MAXIMUM SCALE ATTAINABLE ARE POINTED OUT. WHENEVER LARGE SCALE MAPPING FOR HIGHWAY SURVEYS IS TO BE UNDERTAKEN BY PRECISE PHOTOGRAMMETRIC METHODS, THE SPECIFIC RELATIONSHIP BETWEEN RELIEF HEIGHT IN THE AREA TO BE MAPPED AND THE PHOTOGRAPHY FLIGHT HEIGHT MUST BE FULLY CONSIDERED. GRAPHS ARE PROVIDED TO SERVE AS AIDS IN ASCERTAINING LIMITING CONDITIONS. /AUTHOR/

Media Info

  • Monograph Title: Photogrammetry: developments and applications, 1959
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00202714
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Sep 9 1994 12:00AM