What’s New In ArcGIS 9.2 for CAD: Part 11

This Top Ten List Goes to Eleven!

In the rock-n-roll (rock-umentry) parody This is Spinal Tap there is a scene where visionary lead guitarist Nigel Tufnel is being interviewed regarding some of his creative innovations. One technical innovation was that his amplification equipment was specially made to go one higher than anyone else’s. His amp’s dials went to 11 instead of just 10. When pressed by the interviewer “Why don't you just make ten louder and make ten be the top number and make that a little louder?” ... the confused guitarist in frustration reiterated the significant difference with the refrain… “…These go to 11!”

In the spirit of Spinal Tap let it be known this list top-ten list goes to eleven! Since the publication of the official lists of improvements to CAD interoperability in ArcGIS 9.2 there have been a couple more improvements that have just made it into the software prior to its release.

11a.
AutoCAD Custom Object’s proxy geometry is now supported as ArcGIS CAD features. This means custom objects created with tools like Autodesk Civil 3D or Autodesk Map 3D will be read by ArcGIS as CAD features. The custom object data that may be associated with these CAD objects and the special geometric representations are still locked away from the standard industry interoperability tools in a proprietary Autodesk encoding format. However, for the first time you’ll now see the proxy geometry in ArcGIS.

11.b.
With the addition of the Export To CAD tool in ArcGIS 9.0 I have been able to append to CAD drawings using ArcGIS. However in ArcGIS versions prior to ArcGIS 9.2 a CAD drawing was opened once and cached in memory. Any changes to the CAD file on disk where ignored. In ArcGIS 9.2 the CAD file is refreshed automatically when the drawing is modified. This is especially important when CAD drawing data is published as part of an ArcGIS Server Map Service. These CAD files may be modified while the map is being served. Any changes to the CAD drawings are now reflected in the map service.

What’s New In ArcGIS 9.2 for CAD: Part 10

Leveraging the Improvements to ArcGIS 9.2

I just returned home from Albuquerque after attending ESRI Electric Gas Users Group conference there. It was a very pleasant time to be in Albuquerque and it just happened to coincide with the international hot air balloon festival. It made me think that even a blog like this can be useful when you think that all those balloons take flight because of a lot of hot air! It was nice to meet with all of you who attended the EGUG conference. This group is heavily involved in both CAD and GIS technologies and their questions and feedback are representative of why I do what I do.

Getting back to the topic of this series... Perhaps the most powerful enhancements to CAD Interoperability are the changes made in all other parts of ArcGIS. There have been many enhancements to map navigation, the geoprocessing framework, and new geoprocessing tools. To get a good overview of all the changes in ArcGIS 9.2 you can visit the ESRI.com for what's New In ArcGIS 9.2.

Here are just a couple of my favorite ArcGIS enhancements:

I can now manipulate the wheel of my wheelie mouse to dynamically zoom in and out in ArcMap, and also re-center and pan during the use of any other tool. This allows me to navigate without specifically going back and forth to the toolbar to select different tools. These navigation tools work while other tools are active.

One of my favorite new geoprocessing tools in ArcGIS 9.2 is the ArcView SPATIAL JOIN tool. It allows you to perform a proximity based join between two feature classes, like CAD Annotation and CAD Polylines for example, all within geoprocessing. In ArcGIS 9.1 and previous versions I have to use the ArcInfo NEAR tool or perform the spatial join using the user interface options of ArcMap. The difference being, now I can include the SPATIAL JOIN as part of a geoprocessing model or script.

Geoprocessing iteration has been added in ArcGIS 9.2 for all tools in the form of a batch processing mode and using iteration properties available inside Model Builder. These iteration tools allow me to perform looping operations within models and/or execute any system or custom tool in a batch mode where the variable inputs for the tools are driven from values entered into a grid control.

Model builder now supports the use of model variables or properties used by reference. Any exposed geoprocessing property in model builder can be used as a variable by reference in any other property. Furthermore those values can be concatenate and used much like scripting variable. To use any property in the model as a variable I simply include the text name of the property’s bubble within percent symbols, like this %My Variable%. I can use that notation to concatenate the value of that bubble in other parameters in the model. Using the Model Builder variable in combination with iteration makes Model Builder an even more powerful applications development platform. More logic and workflow modeling can be done directly in model builder without having to move to a scripting environment like python

Remember all of the documentation for ArcGIS 9.2 is already availble online.

Continue to Part 11

What’s New In ArcGIS 9.2 for CAD: Part 9

Georeferencing CAD Drawings

My daughter Holly was on a television game show this weekend. We enjoyed cheering-on the kids. It was fun to be part of the studio audience. The audience was a “character” in the show. We had two handlers who told us when and how to cheer to make the show more fun for the contestants, and more exciting for the TV viewers. The producer and the crew film a show for entertainment, while my daughter competed for prizes; it was interesting to see it all come together. I am happy to report that Holly’s team was victorious, and I was very proud of her regardless.

When CAD files are drawn with a scale, or within a relative coordinates system (ie: lower left corner is (0,0), etc…) their coordinates need to be shifted, re-scaled and or rotated to be usable with in a GIS and its georeferenced view of the world. For all the characters in the map to come together in a useful way they have to share the same coordinate system. In ArcGIS the way to define the parameters for how a CAD’s relative coordinates system needs to be adjusted is using a world file.

ArcGIS 9.2 the georeferencing toolbar has been enhanced to create a world file for CAD drawings. The georeferencing toolbar provides interactive tools to move, rotate, scale, fit to display and snap control points to geometry in the process of relocating a CAD drawing and aligning it with properly georeference features in the GIS. The end result of these interactive repositioning tools is the creation of the ArcGIS world file that stores the parameters for the coordinate shift for the CAD drawing. Whenever ArcGIS reads the CAD drawing it then looks for the presence of the world file and uses the information to apply a coordinate transformation so that the CAD drawing appears in the correct coordinate space.

In previous versions I was left to my own devices for how to define the two sets of coordinates in the ASCII text file that defined the coordinate transformation of a world file. In ArcGIS 9.2 the interactive tools allow meto visually and interactively reposition the CAD file and then save the resulting transformation in the world file.

This is how I use the new tools: When I first load a CAD file with a relative coordinates system, it appears in ArcGIS way out in the boonies some where. So, at first I don’t worry about it and zoom into a position in the map frame of ArcMap where the CAD file should approximately fit . I use the FIT TO DISPLAY option of the georeferencing toolbar with one of the CAD feature classes selected as the target data on the georeferencing toolbar... and presto the CAD drawing pops into the current map frame. If the drawing needs to be significantly rotated, I might use the rotate button on the toolbar to rough it into position and then use the nudge tools and scale tools to get the file close to its final position. Next I use the control points tool to snap to two points in the CAD file and two points on existing Map to get an exact transformation.

To enable interactive snapping to verticies in ArcMap I must be in an edit session. Since CAD feature classes are read/only in ArcGIS I need to temporarily edit some GIS data in the drawing. I need to use the START EDITING option on the editing toolbar, where the target feature layer is an editable GIS layer. I can then snap to any of the data in the map frame using the ArcMap snapping tools. I don’t actually need to edit anything, but rather just turn on and off the snapping. Once I am done defining my two sets of control points, I select the UPDATE GEOREFERENCING option on the toolbar and I am prompted to save the world file. I then terminate the editing session without having to actually make or save any edits.

Continue to Part 10