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I am exporting elevation contours from ArcGIS to a DXF file so that I can FTP the result to another office. The resulting file is extremely large. When export the same contours to a shapefile (from file geodatabase) it not only takes a fraction of the processing time but is 6x smaller in size then the DXF file. This is only the major contours, I still need to create a DXF file from the minor contours and the process is crashing all together. I need to deliver the contours in DXF format. I tried compressing the file but it is still too large. Is there another way?

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Can't the destination program read shapefiles? – Dan Patterson Apr 7 '11 at 16:42
Destination program is AutoCAD. A wrong tool for the job but the person is a key decision maker that does not know how to import Shapefile into AutoCAD nor does he have time to learn. He needs a file he knows how to open. – Jakub Apr 7 '11 at 16:58

4 Answers

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Have you tried using ogr2ogr to convert the shapefile to DXF? It is quite powerful, writes to DXF, and is free to use.

Supported formats

You can download FWTools to make the install process a breeze.

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up vote 4 down vote

Perfect job for FME (www.safe.com) and with it you could also split your data in grid. It's very easy if you use the TILER transformer. You would have many DXF, but at least they would be workable.

And FME is less subject to crash for this kind of job. Note that FME has a demo version.

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am downloading the demo. Does it limit by the number of features to convert? – Jakub Apr 7 '11 at 17:56
No - Full Version - Will lockout after 30 days of installing it. – Mapperz♦ Apr 7 '11 at 18:11
worked a lot faster then ArcGIS for the 5m interval contors but died with "out of memory" on the 1m interval contours. Still a nice little utility. How much is the full version? – Jakub Apr 7 '11 at 18:53
I don't know the price, but it's far from a little utility. It's really useful to transform all kind of format and automation is easy. You have a lot of data or not enough memory/disk to have the problem "out of memory"! – jeb Apr 7 '11 at 22:28
up vote 1 down vote

I'll be glad to help if you need it. I can import shape and create a dxf.
Or a set of dxf files.
If you want to find your own solution you might try creating a grid, and clipping each cell to a seperate dxf file.
He could then re-assemble the draings without much adoo.
Too bad he won't use the tools he has.
Autocad map will edit shape file natively or import it through FDO.
Let me know if I can help.

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Thanks. I've though about splitting it up but ease of use by the person on the receiving end is of utmost importance. I might generalize the raster or triangulate into a simpler TIN then re-create the contours from that... – Jakub Apr 7 '11 at 17:55
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Thanks for the offer Brad. I ended up converting the LiDAR Raster to a mid-resolution TIN and created the a simpler contour file. The raster contours (even though i used a generalized dem) just had too many vertices. – Jakub Apr 7 '11 at 20:43
up vote 1 down vote

Hey, Do you have access to AutoCAD Civil 3D? If so, you can simply type "mapconnect" in your command line and attach to your contour shapefiles. This will also maintain the attribution. The "mapimport" command, will bring the contours in as polylines "without" attribution. You can connect to the data "afterward" if you choose option 2.

Alternatively, you can create a surface from GIS data. Under the "home" tab, you will see "create ground data". In there, you will find a dropdown beside the word "surfaces". From there, select "create surface from GIS data". The rest of the process is pretty self-explanitory. Whichever method you choose (of the three I've indicated), you can simply save to a .dxf format when you're done. This should alleviate the file size issues you're experiencing. Also, bve sure everything is in the datum you want before bringing it in to CAD. It "does not" project on the fly (sadly). Hope this helps, Dano

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