DIGITAL HYPSOGRAPHIC MAP COMPILATION
J Vanroessel · Photogrammetric engineering · 1972
A COMBINED MICRO-DENSITOMETER AND MONOCOMPARATOR IS THE ONLY HARDWARE NEEDED FOR A DIGITAL TERRAIN MODELING SYSTEM, DEVELOPED AS AN INTEGRAL PART OF AN OVERALL RESOURCE INFORMATION SYSTEM. MEASURED X AND Y PHOTO COORDINATES AND ANALYTIC PHOTOGRAMMETRY ARE EMPLOYED TO DETERMINE APPROXIMATE POSITIONS FOR SELECTED TERRAIN POINTS. A TERRAIN SURFACE FUNCTION IS ESTIMATED FROM THESE POINTS USING HYBRID ORTHOGONAL POLYNOMIALS. WITH THIS FUNCTION AND THE DIGITAL MICRO-DENSITOMETER SCAN DATA, CORRESPONDING IMAGES ARE LOCATED WITH A PREDICTIVE POINT MATCHING SYSTEM, MODEL COORDINATES ARE CALCULATED, AND AN IMPROVED TERRAIN SURFACE IS DETERMINED. THIS PORCESS CAN BE ITERATED TO A DESIRED ACCURACY LEVEL. FINAL OUTPUT CONSISTS OF A DIGITAL TERRAIN MODEL AND A COMPUTER-GENERATED HYPSOGRAPHIC MAP OF THE TERRAIN IN THE LOCAL COORDINATE SYSTEM. RESULTS ARE PRESENTED FOR SIMULATED SCAN DATA AND FOR 1:10,000 AND 1:24,000 AERIAL PANCHROMATIC STEROPAIRS. /AUTHOR/