White Papers – Mel Fisher

Preparing AutoCAD drawings for conversion into Arc/Info themes

(This success story describes the process used by AutoCAD mappers during the conversion of AutoCAD maps to Arc/Info themes. It was submitted by one of our marketing partners in Vancouver BC Canada.)

Our clients use MapTools to prepare AutoCAD drawings for conversion to Arc/Info themes in ArcCAD, which we market along with many other GIS/CAD products.

MapTools allows the client to clean-up, reduce and give intelligence to a drawing in a couple of hours instead of weeks or months if they were to use standard AutoCAD techniques.

The process usually starts with PET, or parametric editing, to extract and separate text and send them to different layers having meaning to ArcCAD data capture. For example, a single 3 digit number may be mixed in with other text but may also represent a unique value to a polygon that will become a GIS poly. Simply use the statement – search for ??? – to collect these 3 digit text labels and send them to a separate layer and, if needed, move the text to position it into the polygon, all in one PET statement. Later this text can be captured with ArcCAD to give the polygon theme intelligence and save months of tedious data entry time down the road. PET is also used to organize linework into appropriate layers while at the same time changing into continuous 2D polylines for easy ArcCAD conversion, all automatically.

Cleaning polygons prior to conversion is extremely important, since if there are no dangle nodes in ArcCAD to begin with, then processing and post editing is much quicker. Also, tolerances can be much tighter. MapTools makes both cleaning and subsequent editing much faster and certainly more precise. Many drawing that purport to be clean are not, we have often seen as many as 1300 unclosed polys even after cleaning in ArcCAD, a large task to manually fix. MapTools is used to redo such drawings automatically.

Another very important feature of MapTools is its ability to reduce file size on drawings having contours or rivers, that have been digitized or created by automatic means, such as converted aerial photos, or raster-to-vector conversion. In Forestry or Geology such maps are common, and often choke computer processing by their size. We have reports of 30 minute long regens in AutoCAD on drawings of this nature. Curvefit fixes that problem – period. I can’t recommend MapTools strongly enough for anybody working with AutoCAD maps. But the program is at its most powerful when the user sits down and learns it thouroughly, and is creative with inventing tricks with PET, CLEAN and CURVEFIT.

Mel A. Fisher, P.Eng.President
Geokinetic Systems Inc.
Vancouver, BC Canada