STANDARD SIZE PLAN SHEETS PREPARED FROM CONTROLLED AERIAL PHOTOGRAPHS IN GEORGIA

A BASE MAP WAS NEEDED OF A SECTION OF INTERSTATE 95 IN MACINTOSH COUNTY, GEORGIA. A TOPOGRAPHIC MAP COULD NOT BE COMPILED FEASIBLY OF THIS AREA WITH A KELSH DOUBLE PROJECTION, STEREOSCOPIC PLOTTER BECAUSE OF THE LEVELNESS OF THE GROUND AND THE PRESENCE OF PERENNIAL VEGETATION. A PHOTOGRAPHIC BASE MAP WAS PRODUCED BY PHOTOGRAPHING THE AREA USING 6-INCH FOCAL LENGTH, WILD RC-8, AERIAL CAMERA FROM A FLIGHT HEIGHT OF 1500 FEET. AFTER PROCESSING, THE CONTRACT PRINTS WERE SENT TO THE FIELD WHERE A HORIZONTAL DISTANCE WAS MEASURED BETWEEN IDENTIFIABLE POINTS ON EVERY FIFTH PHOTOGRAPH. FROM THESE MEASUREMENTS, AN ENLARGEMENT FACTOR WAS COMPUTED FOR EACH PHOTOGRAPH. THE PHOTOGRAPHS WERE ENLARGED APPROXIMATELY 3 DIAM TO A SCALE OF 83-1/3 FEET TO ONE INCH. THESE PHOTOGRAPHIC ENLARGEMENTS WERE ASSEMBLED ON BOARDS TO FORM A SEMI-CONTROLLED PHOTOGRAPHIC MOSAIC COVERING THE PLAN AREA OF A STANDARD PLAN-AND-PROFILE SHEET. THE PHOTOGRAPHIC MOSAICS WERE THEN COPIED AND REDUCED TO THE DESIRED SCALE OF 100 FEET TO ONE INCH. IN COPYING THE PHOTOGRAPHIC MOSAIC, THE IMAGE OF THE HIGHWAY CENTER LINE WAS USED TO CENTER THE PHOTOGRAPH IN THE PLAN AREA, AND CENTER LINE MEASUREMENTS WERE USED TO FURTHER REFINE SCALE. THE COPY WAS PRODUCED ON DUPONT CRONAR MASKING FILM TO GIVE A CONTINUOUS-TONE OR LOW-CONTRAST NEGATIVE. THE NEGATIVE OF EACH SEGMENT OF THE PHOTOGRAPHIC MOSAIC WAS INSERTED IN THE PLAN AREA OF THE MAP AND THE COMPLETE PLAN-AND-PROFILE NEGATIVE ASSEMBLY WAS INVERTED TO MAKE IT REVERSE READING. LESS TIME AND EXPENSE WERE REQUIRED TO PRODUCE THIS TYPE OF PHOTOGRAPHIC BASE MAP; FIELD PERSONNEL USING THESE MAPS FOR HIGHWAY LOCATION, RIGHT-OF-WAY, AND/OR CONSTRUCTION PURPOSES WERE PLEASED.

Media Info

  • Media Type: Print
  • Pagination: pp 1-2
  • Monograph Title: PHOTOGRAMMETRY AND AERIAL SURVEYS
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00202833
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Sep 21 1970 12:00AM