The Soft Transcope: A practical method to update natural resources databases

This paper mainly introduces the principle and functions of the Soft Transcope (Yang, 1996), a software package for single airphoto geometric correction combined with automated raster to vector conversion of scanned feature boundaries on an image overlay. Instead of producing a digital orthophoto, this software directly extracts the thematic data layers by scanning the delineated boundaries on an image overlay and converting features represented as raster images to vector form. Then, with the collinearity correction model, compiled by applying digital elevation data and a suitable base for horizontal control, the software rectifies the vector data and registers them to the DEM ground coordinate system. Finally, the system digitally mosaics several corrected adjacent airphotos together and inputs them into a GIS database. The obvious advantages of this software are: 1) storing a vector thematic layer instead of an orthophoto image which reduces disk space requirements, 2) corrected data can be directly input into a database as a thematic layer, 3) cost savings for generating the new thematic layers without expensive photogrammetric equipment and specific training, and 4) suitable accuracy for most natural resources applications.