[postgis-users] RE: postgis-users Digest, Vol 65, Issue 16

Gerry James gerry.james at carteryx.com
Mon Mar 17 14:34:03 PDT 2008

Keep in mind when you are converting CAD files of any type the originator
may not have had GIS datasets in mind when creating the files.  If the CAD
file was created for mapping purposes specifically you may not have any
issues, however, if it was created for construction drawing purposes you may
find that the sheer complexity of the file will lead to extensive lost
information in translation.  CAD files support all sorts of specialized
objects such as blocks, splines, text elements etc. that are not viable in a
GIS dataset.

As a friend of mine once said "the AutoCAD data format is quite Baroque"
meaning it is very ornate and complicated.  It has been my experience that a
direct translation from DWG format to GIS is often times far more
complicated than it looks at the outset.

Having said all this I frequently use Global Mapper (not open source but
quite inexpensive - http://www.globalmapper.com) as it allows DWG files to
be split to point, line and polygon files dynamically during translation.
You can then use FWTools to access shp2pgsql for the translation to PostGIS.

Anyway, hope this is helpful.


Gerry James
Carteryx Geomatics Consultants Inc.
Pitt Meadows, British Columbia


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