Industry Specific GIS Data Models in AutoCAD

My mature Valencia orange tree is full of fruit, and it will have ripe fruit from April thru August, which means as much fresh orange juice as I want to squeeze and drink from the single tree. My lemon tree is still small, but it usually has at least one ripe lemon on it every month of the year. I planted a baby avocado tree two years ago, still no fruit…

I reap the fruit of the previous owner’s planting and care of my orange tree. The lemon tree I planted is starting to produce, and the avocado tree is an investment in the future for me.

One free benefit of ArcGIS for AutoCAD that I can start working with right away is accessing ArcGIS map services in AutoCAD with ArcGIS for AutoCAD. As a GIS administrator I can immediately connect the AutoCAD professionals in other departments, and AutoCAD-based contractors outside my organization by looking at the common and direct view of the enterprise GIS basemap through a map service.

Another benefit that is growing in importance is the ability for these same AutoCAD users to create GIS-ready data with the tools in ArcGIS for AutoCAD that build content according to the mapping specification for drawings.

I can use industry specific GIS data models defined by various industry experts for GIS in AutoCAD too! Within ArcGIS I simply export a sample geodatabase like the Water Model available on ESRI.com to an AutoCAD file using the ArcGIS EXPORT TO CAD tool available with ArcView, and presto I have the water model industry schema designed for use in GIS within AutoCAD according to the mapping specification for drawings! Used as an AutoCAD template file, blank versions of the schema can be passed along to others to fill up with water-model content, I know that when the CAD data is brought back into ArcGIS it will be readily usable.

Time to pick some more oranges.

Editing GIS Data in CAD: Attributes

I rented a house on vacation. The house was furnished with cooking utensils and the alike. We packed just our personal stuff that we intended to enjoy while we where there in the new environment. It wasn’t like home; lots of things were different, how things were organized, different interfaces to the appliances etc. We benefitted from having those things there, and not having to pack them. Not surprisingly their stuff was chosen and adapted for a more rugged and minimalist life at the beach. We cooked and played with their stuff, using stuff we brought or bought while we where there. Like all good vacations we took back family memories and experiences that updated and recharged various attributes of our lives.

ArcGIS desktop reads and writes both AutoCAD and Microstation files. In the case of AutoCAD files, ESRI’s mapping specification for drawing allows attributed GIS features to be included in plain AutoCAD files. So what good is that? It is useful for me to create AutoCAD data that will also be used as GIS data and to comply with GIS submittal requirements, but what about as a means for editing ArcGIS data in ArcGIS data sources?

If I want to allow AutoCAD users to make attribute-only edits to my ArcGIS data I can use ArcGIS geoprocessing tools like EXPORT TO CAD, JOIN and CALCULATE to facilitate the workflow. By exporting ArcGIS data to an AutoCAD file with the EXPORT TO CAD tool, the resultant AutoCAD file retains the unique object identifier and feature class organization and attributes of the source ArcGIS feature class according to the mapping specification for drawings. I can make attribute edits to the copy of the data in AutoCAD with ArcGIS for AutoCAD, or any other MSD compliant application. After attribute changes are made to that copy of the data, I can JOIN the AutoCAD version of the data to the original ArcGIS GIS feature class, based on the unique object identifier field and use the geoprocessing CALCULATE tool to move the attributed data from the CAD-based copy of the data to the geodatabase version for each of the attribute fields I want to update.

Good Friday Fact Check

I’ve been reading some descriptions and interpretations of ArcGIS for AutoCAD from various sources. There seems to be some re-occurring confusion despite attempts to be clear about what it is and does. Perhaps this list will help.

1. ArcGIS for AutoCAD does not require ArcGIS Server. ArcGIS for AutoCAD is a free download that works on top of plain AutoCAD. All of its functionality can be used completely for free. I can access any free published map services with ArcGIS for AutoCAD as long as I know the URL and have access.
   
   Furthermore, I can view, modify and create GIS-ready data according to the Mapping Specification for Drawings using the feature class management tools that are provided in the free ArcGIS for AutoCAD application, which does not have anything to do with map services or ArcGIS Server. ArcGIS for AutoCAD has tools that work on stand-a-lone AutoCAD to create feature classes with attributes that are recognized by ArcGIS. ArcGIS desktop can directly read the entities in the AutoCAD files as GIS feature classes.
   
   
2. ArcGIS for AutoCAD does not publish map services. To publish map services you need a GIS server, like ArcGIS Server. To publish map services I need a licensed copy of ArcGIS Server. ArcGIS for AutoCAD is a client of ArcGIS Server Map Services, not unlike the free ArcGIS Explorer product is a free desktop client.
   
   
3. ArcGIS for AutoCAD is not designed to compete with AutoCAD based GIS ad-on software. Rather it is a product designed to assist me when I am working with ArcGIS workflows that include AutoCAD. It helps me interoperate between AutoCAD and ArcGIS because I have a way to attribute CAD entities that ArcGIS understands and also clarify how GIS data is organized in my AutoCAD file.
   
   
4. ESRI's mapping specification for drawings is not a software product. It is simply a specification. It is a piece of paper. It is an agreement between ESRI and the AutoCAD user that if AutoCAD files are structured in a certain way they will be understood by ESRI as having a certain format and organization of data and content. It is not meant to compete with any other workflows or software, but rather has been introduced as a proactive means to support ESRI customers that work with AutoCAD or extended teams that use AutoCAD. ArcGIS for AutoCAD provides a free user interface to the mapping specification for drawings inside AutoCAD. ArcGIS software reads and writes this style of AutoCAD data.
   
   
5. ArcGIS for AutoCAD does not provide a means to directly edit ArcGIS geodatabases. It may in the future, but the current release does not generate AutoCAD entities from map service content or any other means supplied in the application. Nor does it allow me to modify features from a map service or other ArcGIS data source.
   
   
6. ArcGIS for AutoCAD does not currently create or edit any other form of GIS data accept pure .dwg data formatted according to ESRI’s mapping specification for drawings. That is a good thing. The data is still pure .dwg with just enough non-graphic entity data to make the entities in the drawing directly usable as feature classes in ArcGIS. ArcGIS data exported to .dwg files is a snap-shot copy of the GIS content written to a .dwg file. It doesn’t mean I might not have a clever workflow to move data back and forth, but the data is not otherwise linked by software.
   
   
7. ArcGIS for AutoCAD supports ArcGIS Map Services and these images are not simply raster images. Map Services are georeferenced, scale dependent cached or dynamic services that are implemented inside of AutoCAD as a custom object that has various configurable behaviors that control the visibility of the entire map service or individual layers in the map service. ArcGIS for AutoCAD also provides a means to query the attribute records of features contained in the map service provided that functionality was published in the map service by ArcGIS Server.
   
   
8. ArcGIS for AutoCAD supports many, many coordinate definitions, all the same nominal coordinate systems supported by ArcGIS Server using a WKT (Well Known Text) string embedded in the .dwg according to ESRI’s Mapping Specification for Drawings.
   
   
9. ArcGIS for AutoCAD does not use any of the functionality of Autodesk Map 3D. Autodesk Map 3D proprietary data organization and coordinate systems are not accessible to the plain AutoCAD user or commercial applications that read standard .dwg files, like ArcGIS for example. It doesn’t mean they are bad, it just means they do not promote interoperability with ArcGIS as a data source. ArcGIS for AutoCAD will co-exist with ad-on’s to AutoCAD including Civil 3D and Map 3D insofar as these include AutoCAD.

Perhaps there may be additional questions that come up in the comments. I’ll add them to the bottom of the list… Starting with #10.

Missing Link

Oops, forgot to add the link to the AutoLISP routine in the original version of the last post.

One More Time Around the Block

My birthday is coming up soon and I’m planning on celebrating with an Easter vacation on the beach. The retreat is also doubling as our summer vacation, and payback to my wife for abandoning her every weekend and evening to coach basketball this winter. My daughter is also planning to celebrate her belated birthday at the beach. Her birthday party was also delayed because of the basketball schedule.

In a previous post I discussed some of the reasons I may want to continue to use block attributes as a means to attribute point feature in AutoCAD even when using the Mapping Specification for Drawings to create data for use in ArcGIS.

Here is a new AutoLISP Routine that will build the MSD feature class schema in a drawing based on all of the block definitions and attributes on those block definitions that are contained in a drawing. The included AutoLISP command is called esri_BlockToFC. This tool is useful to generate new MSD feature classes and attributes when moving away from relying on AutoCAD block attributes as a means to store attributes in an AutoCAD file on Point, Line or Polygon entities. It will use the tag name of attributes and generate typed fields according to the any default value you may have specified for a particular ATTDEF. If the default value for the ATTDEF called diameter has a default value of 4.5 then this lisp routine will create an MSD feature class attribute with a floating type attribute. I can override the type of a field using the feature class management panel of ArcGIS for AutoCAD.

The MSD feature class filter criteria created for each feature class will be based solely on the block name from each block. I generally do not need different feature classes for every block in my drawing. I will likely need to use the ArcGIS for AutoCAD feature class management panel to rename feature classes and consolidate blocks, or remove or re-define the filtering criteria for the feature classes that get created. In the case where I might have blocks holding attributes for lines or polygons I will change the feature class type and the filtering criteria. I can use these tools to automate the process of copying attribute schema from my existing block attribute-based data creation workflows to take advantage of the MSD capabilities of ArcGIS for AutoCAD and ArcGIS Desktop. If nothing else it is an example of customizing the ArcGIS for AutoCAD application in a useful way with AutoLISP.

Geoprocessing, MSD and .NET

“Nothing but net” is a welcome refrain for basketball shooters. I hope you will find these .NET samples connecting AutoCAD with ArcGIS Geoprocessing located on ArcScripts equally valuable.

I enjoyed meeting with the CAD savvy developers at ESRI 2009 Developers Summit. Hello again to all of you who attended our CAD technical presentation at the conference or that met with the CAD team at the breakout session. Karen the co-presenter and author of the samples, has posted the sample code on ArcScripts. This code was demonstrated during our session to connect AutoCAD .NET to ArcGIS’s Geoprocessing tools via .NET for the purpose of extracting data from ArcGIS sources as CAD data. Conversely the samples also include adding data from CAD drawings into ArcGIS data stores. These coding samples are available here on ArcScripts.

The samples are a concrete programming examples of the topic I introduced in a recent blog posting on bouncing CAD files off of geoprocessing.