PMCAD: Photogrammetric‐Based CAD System for Traffic Accident Mapping

Abstract

A low‐cost, digital, three‐dimensional photogrammetric mapping system has been successfully developed and implemented on a microCAD system. Code‐named PMCAD, the system allows both two‐dimensional line maps and three‐dimensional wire‐frame or solid models to be captured into CAD databases from nonmetric cameras. The mathematical algorithm is modeled on the Direct Linear Transformation (DLT) and implemented on a microcomputer. Preprocessor and postprocessor software developed to work in cooperation with the DLT algorithm, allows digital data to flow efficiently from the digitizer into a CAD system for 3D graphics display.