What's New In ArcGIS 9.2 for CAD: Part 3
When dealing with CAD data in ArcGIS you never know how a subtle varience in the CAD properties might be useful in distinguishing one potential GIS feature from another. Although there are currently more CAD properties supported in ArcGIS 9.1 than most people need the addition of several new CAD properties target some useful omitions.
Worthy of note are the CAD properties Elevation, DocPath, Angle and the collection of CAD Layer properties.
Although there is a specific definition of the Elevation property in AutoCAD, in ArcGIS 9.2 that definition has been loosened so that points, even 3D points that have a Z’ Coordinate will have the elevation value included in the table in addition to Z’ coordinate being a part of the 3D geometry. A related improvement is that the ArcInfo Export to CAD geoprocessing tool now supports more fully the Elevation field to control the elevation of CAD entities that are exported.
The new field DocPath is included in ArcGIS 9.2 for all CAD feature classes. In this way I can keep a record easily of which drawing file I am working with. I can retain this value during conversion to keep a record of where the information originated. A related benefit is the automatic hotlink feature of ArcGIS that recognizes path names in ArcGIS tables. If you use the identify tool in ArcMap for example on a complicated map that may contain several complicated and vertically tiled CAD drawings, you can identify a single feature and then in the grid control of the Identify command you can click the hotlink icon to Launch the CAD application on you desktop that is linked to that drawing file extension. So if you have AutoCAD on your desktop you can use ArcMap to launch the appropriate CAD file by simply browsing a key map of CAD files in ArcGIS.
The rotation value of Cells and Blocks and other point feature is now included in ArcGIS CAD Point feature classes. This was added so that I can now rotate symbols in ArcGIS based on the same rotation values used in the CAD file. The new rotation values are in decimal degrees rather than radians (so you don’t have to do the math).
Another addition are the Enity/Layer symbology properties for CAD entities. In ArcGIS 9.1 and previous versions there was a single value for CAD properties such as Color. I did not know if that value was the entity color or if the entity was BYLAYER or BYBLOCK, all I could discern was that that was its display color. In ArcGIS 9.2 you get the display properties, entity properties and layer properties to distinguish between; for example, a red entity and an entity on a layer colored red, with an entity color of BYLAYER.
There are several other CAD properties that have been added that are maybe a little more esoteric, but potentially useful.