CAD and GIS - Apples to Apples Please

I remember my first position as a GIS project specialist for a state government agency and trying to bring in a DXF file into ArcView 3.2 and how time and manually expensive it was. Well that was some time ago and while ESRI has started to create tools to try to integrate CAD and GIS information its clear that the GIS giant is still comparing its GIS tools to base AutoCAD. Ideally any comparison and real integration should be with the Geospatial CAD programs like AutoCAD Map 3D where these two technologies can be integrated seemlessly. When I was looking at some of the latest and greatest information on CAD and GIS integration I quickly found this whitepaper from ESRI, and while I appreciated the historical perspective, the comparison between mapping in AutoCAD and GIS is misleading. For anybody that is looking to draft and design non-geographic information a simple seat of AutoCAD fits the bill. With the precision editing and design capabilities that a CAD package provides its the best tool for data creation. But for the user that is going to design, create and manage geographic information and wants the design capabilities of a CAD package they should be using AutoCAD Map 3D. AutoCAD Map 3D fits perfectly between the traditional CAD and GIS space. Its built on AutoCAD giving the user all of the editing and precision tools for data creation while also giving stylization, data management and analysis tools for GIS. Lets take a close look at the misconceptions that are still largely misunderstood today.

Misconceptions taken from ESRI whitepaper CAD and GIS integration:

"CAD is drawing-based and manages data as drawing files or a set of drawing files.The set of drawing files can be a set of map tiles that share a common coordinatesystem but are physically disjointed. The main product of a CAD system is a papermap."

AutoCAD Map 3D can read natively DWG files of course, but can also manage information in data models like ArcSDE, Oracle, SQL Server and personnal geodatabases as well. This is accomplished using FDO.

"CAD layers are nothing more than an entity property, such as color or line type,sometimes enhanced with the use of a layer tag. CAD standards do not alwaysseparate object systems by layer; objects could be differentiated just as well by coloror line style."

AutoCAD Map 3D can create object data and data classification on AutoCAD objects. CAD standards today on cadastral information should manage attribute information within this environment or consider centralizing data into a central datastore using FDO. Ideally this could be done ArcSDE, Oracle or SQL Server.

"GIS is database-oriented and thus tends to handle data in a single seamless database.Because GIS has always held the possibility of managing data over a widegeographic extent, it includes many tools for map projections and for handling largedata volumes."

AutoCAD Map 3D can handle data not only from a single seamless database, but works to integrate data from multiple different sources allowing greater integration between traditional GIS data stores and CAD formats.

"GIS Shows relationships between features (valves are connected to pipes as a database requirement)"

AutoCAD Map 3D can create topologies on AutoCAD objects for analysis and highlight spatial relationships

"GIS Scales from one person to hundreds with no changes in the system interface"

AutoCAD Map 3D allows multiuser access to DWG files as well as datastores like ArcSDE, Oracle, SQL Server to name a few.

"GIS can use CAD data without conversion. ArcGIS, for example, can display CAD data in DGN, DWF, and DWG files directly and in the same map display asGIS layers. ArcGIS symbolizes CAD data as defined in the CAD file."

AutoCAD Map 3D uses FDO technology to access many different industry standard datastores directly without the need to translate the data. It also allows direct read and write access and as a result reduces redundant data and data loss from translation processes.

"GIS can control how the data is symbolized and use the CAD data in GIS analysis solong as the CAD data is added as simple point, line, and polygon features to a GISlayer. If you create a layer file from a CAD feature class, you can change thesymbology used to draw its features, join attributes stored in separate tables to thelayer, and select which features to display according to their attribute values."

AutoCAD Map 3D can control sylization through object classification . You can also create and manage stylization and thematic mapping that includes smart labeling and transparency.

These are just some of the glaring misunderstanding today when comparing AutoCAD to GIS. Ironically the title of the ESRI article is "CAD and GIS - The right tool for the job". Well anyone that is going to compare these two technologies would do well to compare apples (AutoCAD Map 3D) to apples (ArcGIS) and not apples (ArcGIS) to oranges (AutoCAD). AutoCAD Map 3D is what should be used when integrating traditional GIS (ESRI) with CAD data and vice versa. In fact AutoCAD Map 3D is specifically aimed at integration and any ESRI installation that needs to integrate CAD information would benefit from a license of it. So, allow me this little consession, but if you want to integrate GIS and CAD the right tool just might be AutoCAD Map 3D.

Good Mapping, Neal