Question

Conversion of 3D CAD to GIS with Custom Coordinate Transformation (Vertical Datum Issue)

  • 26 October 2017
  • 1 reply
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Seeking to convert a large 3D AutoCAD (dwg) project into ESRI Shapefiles (points, lines, and polygons). Converting dwg to individual shp was accomplished using FME and the shapefiles are 3D so now I need to read .shp, tranform the x, y coordinates, keep the z coordinate intact, and output as a new .shp into the Greek Greed (GGRS87). However, my shapefiles have no spatial reference because the original is an older Greek system based off HATT projection and Bessel Elipsoid 1841. This system developed by the Greek military divides the country into 109 zones/mapsheets. I am using mapsheet 257 ????? ????????? and want to convert all my points, lines, and polygons from this older system to the more modern GGRS87. Outside of FME I have a formula to convert x,y but it strips out z-values. Therefore, I am asking is it possible in FME define this older spatial reference, apply a xy coordinate translation, preserve the z values, and write out in GGRS87 (which FME supports)?


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