Convert AutoCAD drawings to a shapefile format
AutoCAD is a great tool to edit and manipulate drawings, but sometimes we need to convert the information contained in AutoCAD drawings to a different format in order to study it from a different perspective.
Being able to interoperate between different applications to take full advantage of their differing capabilities is essential and is part of what I cover in my CAD training courses.
An example of this is the shapefile format, which is used in Geographic Information System (GIS) software. GIS applications are used to edit and analyse spatial information and have many applications in fields like engineering, transport or telecommunications.
There is a command that serves that purpose, the MAPEXPORT command. Please note that this command is not available in AutoCAD. In order to use it, you need to have AutoCAD Map 3D or Civil 3D installed. This command is easy to follow but you need to be aware of the different options in order to include all the information that you need in the shape files.
We will now progress step by step through a CAD training exercise where we export all the features from an AutoCAD drawing to a shapefile format.
First, type MAPEXPORT in the command line from AutoCAD Map 3D or Civil 3D. In the window that pops up, browse to the path in your computer where you want to store the shape files. Select ‘Shape Multiclass’ in the type drop-down and type a name for the folder that will contain the files. A new folder will be created with this name and the files generated will be stored in it. In this example we are going to call this folder ShapeFiles, as shown below:
You can also select an existing folder but it is not recommendable. In fact, if you choose an existing folder you will receive a warning stating that the files that you create may conflict with existing ones. It will then give you the option to append the new files, overwrite existing ones that may exist with the same name or cancel this dialog to be able to change to a different folder.
In the next window, go to the Selection tab and click on the ‘Select all’ option to select all the objects contained in the drawing.
There are two alternatives for manual selection. If you click on the first icon you can click on the objects in the drawing that you want to include. Clicking on the second icon will open the ‘Quick select’ window, where you can filter the different objects by their type and properties.
You can then add additional filters to your selection by selecting the layers or object classes that you want to include. Notice that an asterisk is included in the Layers field by default, which means that all the layers will be included in the filter.
On the Feature Class tab, select ‘Create multiple classes based on a drawing object’.
If you want to include some particular attributes in the Shape files, you can do so by clicking on the ‘Select Attributes’ button and ticking the ones you are interested in.
Finally, go to the Options tab and tick ‘Treat closed polylines as polygons’. Other options available in this tab include the possibility to convert the coordinates to a different coordinate system or to choose between two or three dimension shape files, by clicking on the ‘Driver Options’ button.
If you click OK, a group of files will be created for each feature, as shown below:
As you can see, a group of files will be created for each of the GIS features (such as points, lines or polygons) and its associated attributes. You can now open these files directly in your GIS application or add them directly to the central directory of a ZIP archive. The latter makes it easier to send the information to a third party, should you need to.
CAD training is an excellent way to brush up on your skills and provides you with more accurate and efficient ways of doing things on the software.
If you are looking for CAD training, take a look at our full range of courses here