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Monday, October 28, 2013

How Convert Auto CAD.dwg File to Shape file?

Which is the right form to convert Auto CAD.dwg file to editable shape file?

converting from CAD .dwg to GIS is very simple using the CAD to Geodatabase Tool. However, you can't convert from CAD to a .shp file, you have to convert to a geodatabase feature class which is essentially the same thing but better for many purposes like topology and relating feature classes to one another (When you are first learning about Geodatabases, know that the terms "shapefile" and "feature class" are nearly the same thing just stored in differnt ways). Once the CAD Data is in a geodatabase you can always export the feature class to a shapefile, just know that if your CAD line work has curves in it you will lose some curve data converting it to a shape file.

This is because an advantage to geodatabases is that they store mathematical geometry. When lines or polygon features have arcs (maybe circles too?) drawn in them a geodatabase will store the arc as a mathematical geometry which keeps the curve of the arc nice and smooth where a feature saved as a .shp file will loose the geometry of the arc and convert the arc to a bunch of vertices connected by short lines, loosing the smooth arc. I work in Public Works and we deal with a lot of pipes, when those pipes have curves in them a feature class is much more usefull than a shape file. (The data on my screen in the attached image is an example of CAD data that has been converted to Geodatbase, all of my curves are identical to the CAD data.)

So how do you do it?

1) First create a File Geodatabase in ArcCatalog by rightclicking in a folder and selecting New>File Geodatabase (see attached image).

2)Next, in either Arc Map or ArcCatalog, you open the CAD to Geodatabase tool in ArcToolbox > Conversion Tools > CAD to Geodatabase (or you can use the search tool as shown in the attached image).

One thing to be aware regarding the inputs in the CAD to Geodatabase tool: You have to be a bit carefull naming your new dataset. Unlike shapefile names where you can name them pretty much whatever you want, spaces and symbols are no good with some things. Use normal letter & number text characters only or your conversion will fail.

Also if you are unfamiliar with using feature classes, know that the same rule applies to naming feature classes. However feature classes do allow for underscores ("_") though I have found that even these can be an issue at times. Therein I name my featureclasses with a combination of capital and lowercase letters (i.e. sdDrainageBasin, MiscUndergroundObstructions).

You can read about the details of the CAD to Geodatabase tool here:http://help.arcgis.com/en/arcgisdesk...0000001z000000

There you go!

My apologies again for having no experience with the Spanish version of ArcGIS, I hope this is all similar for you.

Wish you the best!
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