What's New In ArcGIS 9.2 for CAD: Part 3

More Properties

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.

Continue to Part 4

What's New in ArcGIS 9.2 for CAD: Part 2

I could make a case for the fact that the pay at the pump credit card transaction technology is one of the most useful innovations of all times, ranking up there ketchup in a squeeze bottle and the internet. That is if it weren’t for the fact that there are so many different interfaces that have arisen for the different pumps. In the glory days of pay-at-the-pump you would swipe your credit card and select the gas you wanted to use and pump away.

Then the internet birthed the profitability of identity theft and the interface became more complex, often you must enter a zip code now… another disturbing variation was in invent of the option to not receive a receipt, car wash… etc. Other times the interface needs you to tell it if you’re going to pay cash or debit or credit (like it can’t tell when you swipe the card!) some want you to confirm with a [Yes] others with the [Enter] key. And, of course there are several variants as to where the [Yes] and or [Enter] keys are located. You can see for yourself that this is the essence of poor design. Think of all the gas stations you’ve been to where the gas station owner, tiered of answering everyone’s questions about the broken pump, has taped a big arrow or circled the magic key with a permanent marker!

A standardized interface would help me not have to be apologetic about my vote for pay-at-the-pump’s nomination to the technology hall of fame.

Change for the sake of change is just confusion unless the change was designed to eliminate an existing confusion. The original consensus that spawned the decision to create one file icon for the Feature Dataset of a CAD file (blue folder) and another file icon (white) to represent the Drawing Layer view of a CAD file has been lost. Scanning the user forums and viewing statistics from logged technical support calls regarding the subject, provided a compelling argument that something was wrong with the current arraignment. People didn’t know which representation of the data to access. However when the data is organized together in one folder there is a much clearer picture of how ArcGIS sees a CAD file.

Instead of seeing two files in the file system browse tree for every CAD file you will now see just the single CAD feature data set (blue icon). Inside the CAD Feature Dataset you will still see the standard CAD feature classes (POINT, POLYLINE, POLYGON, ANNOTATION and MULTIPATCH); these are the original GIS feature sources available from the CAD file. In ArcGIS 9.2 the CAD Drawing Layer (the white file icon) is included inside the CAD File Feature Dataset. As described in previous posts this icon represents the entire CAD file as a single source of geometry that can be used inside ArcMap as a single layer.

Additional improvements to ArcGIS that I will discuss in this series will help make the case that this CAD Drawing Layer may fade in importance and may in the future disappear all together…

Continue to Part 3

What's New in ArcGIS 9.2 for CAD: Part 1

My daughter Evie has made tremendous strides in her swimming this year. She is only two and a half but can already swim the length of the pool, albeit closely monitored. Entirely self-taught (sister encouraged) she can float on her back, float face down, move backwards while kicking, climb out of the pool from any edge, grab the pool edge from anywhere inside the pool, can pull herself hand-over-hand round the entire edge of the pool, she can tread water for minutes at a time, and performs a modified crawl stroke with her face under the water, stopping to take a breaths while treading water. The secret of her success is immersion. She has been swimming every single day since the summer started.

Much to Grandma’s displeasure, she often ventures into the “deep-end” without hesitation. My 13yr old is quick to point out that for Evie (who cannot touch the bottom of the pool at any point accept the first and second step), the entire pool is the “deep-end”. In that way she has an advantage; she has no prejudice for one level or the other, everything is over her head!

In the spirit of something new, lets talk about the things I like most about what is coming in ArcGIS 9.2 as they relate to GIS and CAD Interoperability.

Top Ten New For CAD in ArcGIS 9.2 :

1. The ArcGIS CAD Drawing Layer has been moved into the CAD Feature Dataset. (The white icon is now found inside the blue folder).
2. The CAD Attribute table of a CAD Feature Class includes More CAD Properties. (Notable additions are an angle value, the CAD file name and an elevation value.)
3. Annotation/Text Support has been Improved. (Better CAD TEXT Rendering and Better TEXT creation.)
4. The CAD Property Sheets have been standardized to work the same as other ArcGIS feature classes.
5. ArcGIS includes a help section dedicated to working with CAD data.
6. CAD Feature Classes are rendered in ArcMap using information from the CAD drawing. (Where possible the CAD colors, line styles and fonts are used by default to drawn features in ArcMap.)
7. When an entire CAD file is added to ArcMap the five standard CAD feature classes are organized in the Table of Contents as a Group Layer.
8. AutoCAD Block Attributes and Microstation Tag elements are included in the CAD Annotation feature class. (Now tags and block attributes can be used as annotation without having to use the Label tool to see the information on the map.)
9. The ArcMap Georeferencing toolbar has been modified to support the interactive georeferencing of CAD files. (You can use the tools to fit, rotate, nudge and snap a CAD file into its proper coordinate space. And, then have it automatically generate a world file (.WLD) for you.)
10. The biggest improvement in my mind for CAD interoperability in ArcGIS 9.2 are the other non-CAD-Specific improvements to ArcGIS 9.2, which Include: Batch processing of any geoprocessing tool, Iteration capabilities in Model Builder, Model Builder Variables, Roller Mouse Pan/Zoom navigation in ArcMap, The AutoCAD and Microstation Image Server Clients, ArcGIS Server Map Services with embedded CAD data, … and more.

Continue to Part 2

Exporting Attributed Data to CAD: Part 5

Microstation MSLinks

Like the North Pole in December, the weeks leading up the ESRI International Users Conference are filled with many GIS elves busily putting together presentations, writing sample code and making big pushes to finish software. This year was no exception. Now that the successful event has passed, I’d like to say hello to those I met in person in San Diego and thank you for your kind words regarding my presentations there, and your positive comments about this BLOG.

In my last post I talked about AutoCAD extended entity data (EED/XData). Microstation design files have a similar albeit more useable form of “xdata” that has been used to store extra information on entities that can be used to indicate a database record in a table to which a Microstation drawing element can be linked. Better yet Microstation has standard user interface tools to manage these links. This make the creation of MSLinks and a companion database table a valid and useful way to store GIS attribute data on Microstation drawings that are generated from ArcGIS feature classes.

Using MSLinks is a traditional means to link design file data with data stored in an external table. The ArcGIS Data Interoperability Extension can make use of this data structure when Creating CAD data from GIS data. Use the MGE/Geographics format as the output format when you export Microstation drawings from ArcGIS's Data Interoperability Extension. The MSLink will be populated with a value that corresponds to a record in a table that gets generate as part of the creation of the Microstation drawing.

The Microstation MSLink technology is pretty straight forward. An MSLink is an integer that coorespondes to the record number of a table. A companion value called and MSCatalog value can also be stored on the element, which is another integer that coorespondes to numbered list of tables (Catalog). In certain applications the two values together can point to a specific record in a specific set of numbered tables.

Note: Exporting Microstation files with MSLinks is not available in the ArcInfo EXPORT TO CAD tool.

Exporting Attributed Data to CAD: Part 4

Nasty Grams and X-Data

Last week some 13,000 people converged on San Diego to share and learn about GIS stuff. I had a great time listening to all of you who came to discuss GIS and CAD Interoperability. I had the opportunity to share two technical sessions last week and I hope it was helpful for those who attended. For those who attended you got a good glimpse at the new technology available in ArcGIS 9.2. I hope to cover that topic next in this BLOG.

Wednesday of last week I was flying high with relief after successfully presenting one of my two technical sessions. I was pleased with the reaction from the attendees who stayed well after the presentation to ask great questions. However, when I got back to my car I was met with a nasty-gram written on a napkin and placed under my windshield wiper. The note was an anonymous self-censored expletive (they replaced three letters of some of the four letter words with “%#$”). The note was chastising me for not pulling fully into the parking spot. Certainly looking from the back it did seem like I had performed a pretty bad job of the parking task.

However, as the person was placing the note under my windshield they certainly must have noticed that there was a concrete utility access stairway that jutted out from the wall in front of my car (that I was almost touching). The astonishing thing to me is that even when faced with the spatial reality of the situation they felt that they still needed to “share the love”. Perhaps they didn’t want to waste the paper and all the effort of writing the nasty message? ..Well at least I get the opportunity to vilify them publicly here.

The lesson … things are not always as they seem! Further investigation can result in better understanding of obstructions, options and opportunities. One such hidden opportunity to store attributes in AutoCAD is the use of AutoCAD Extended Entity Data (EED/Xdata). Both the ArcGIS Data Interoperability Extension and the ArcInfo EXPORT TO CAD tool support the creation of AutoCAD Extended Entity Data.

Unlike block attributes that are un-typed and only available associated with a BLOCK INSERT entity (which is essentially a point), Extended Entity Data can be attached to any AutoCAD entity and can be typed (Integer/Real/String, etc…). The major short coming of Extended Entity Data is that it is not supported by the user interface of AutoCAD itself. This means there is an appalling lack of ways to access it, or make use of it in AutoCAD. One needs to use a custom application or coding sample to even view the data. Unlike block insert attributes, where a standard AutoCAD command like DDATTE can be used to view and edit block attributes.

Use Extended Entity Data to store GIS attributes in AutoCAD when you are confident that you can customize AutoCAD to make use of the results. You can use the ArcGIS Data Interoperability Extension or the ArcView IMPORT FROM CAD tool to read Extended Entity Data on AutoCAD entities.