GIS CAD Interoperability

FDO, Shapefiles and ArcGIS

2009-11-06T15:19:00.000-08:00

My daughter’s high school basketball team had the opportunity to play at the Staples Center this week in Los Angeles for their first pre-season basketball game of the year. It was a great experience for the girls. Our point guard even buried an NBA length three-pointer during the game! Our opponents were a team from Lancaster that we will play twice more during the year. Although the court was the same size as some of the college venues we play at, the seating capacity was a lot larger. The additional markings on the floor, the wide key and distant 3 point line, also told the story of how others who play on this court are playing at a much higher level.

For existing Autodesk Map 3D users the ability to read and write Shapefiles is a useful feature, likewise the access to simple feature layers stored in ArcSDE using FDO. You can even add to that working with WMS map services served up by ArcGIS Server that are similar to the Map Service capability of ArcGIS for AutoCAD, but without the ability to identify features.

If you use Civil 3D the included Autodesk Map 3D functionality gives you access to Shapefiles and ArcSDE simple features you can use in the process of design.

If the main reason I use Autodesk Map 3D is to read and write Shapefiles to work with ArcGIS than I'd say there is an easier way. ArcGIS for AutoCAD working with plain AutoCAD files is superior to using tools that read and write Shapefiles, simply because the support in ArcGIS of the resultant AutoCAD files is better. Namely the attributed feature classes inside AutoCAD files that are created and read by ArcGIS for AutoCAD and ArcGIS desktop are self-contained in the AutoCAD file and can include curves and annotation. The simple features in Shapefiles don’t support annotation or curves. Software that reads and writes Shapefiles in AutoCAD adds another level of cost and complexity; ArcGIS for AutoCAD is free and works on pure AutoCAD entities within a single AutoCAD file. But if I have Civil 3D it’s not a bad way to go.

When considering the Autodesk Map 3D FDO connector for editing however, I must be concerned not only about the lack of curve and annotation support, but also in the fact that the GIS data in ArcSDE may be participating in a geodatabase, for which the ArcSDE API used by FDO has no awareness. The blind simple features edits of FDO made directly to ArcSDE can and will ignore important data integrity rules established in a geodatabase, so be careful.

The girls are now 1-0 in the pre-season.

ArcGIS-Ready AutoCAD Template Files

2009-10-22T15:55:00.000-07:00

I need to compel my children to do things that are good for them, and good for the family, but they may not always see it that way. Whether it’s eating healthy or getting to sleep, or not watching TV all day, even simple things can become a battle. Routines and schedules can do a lot to help set a foundation for success. Other times I just need to set up circumstances where they can’t fail.

AutoCAD template files are most often used to pre-define layers and symbology to support my CAD standards. Using a template file with mapping specification for drawings feature layer definitions allows me to support both a CAD standard and a GIS schema at the same time. AutoCAD drawings files that contain mapping specification for drawings feature class definitions can subsequently be edited by any software that can edit the .DWG file. Because the feature layer definitions of ArcGIS for AutoCAD are stored as standard graphic and non-graphic entities in the DWG file, any software that can edit a 2007-2009 .DWG file can be a viable ArcGIS data creation tool.

Without ArcGIS for AutoCAD I would not have a way to edit any feature attributes that might also be defined as part of the feature layer. My edits would be limited to creating feature class geometry. But I can create feature class geometry in AutoCAD LT, plain AutoCAD without ArcGIS for AutoCAD loaded, or even Microstation (although I've not tired it, I would expect versions of IntelliCAD would work too). All of these can create entities in a DWG file that are recognized by ArcGIS, and ArcGIS for AutoCAD. By simply following my existing CAD standards with feature class enhanced template files, I will be populating ArcGIS feature layers no matter what tool I use. The key to my success is that the feature layer definitions are stored as filtering information on the contents of the file, what ever that ends up being.

Here is a short video of creating an AutoCAD template file that contains ArcGIS feature layer definitions...

Creating Multiple CAD files from ArcGIS

2009-10-13T11:26:00.000-07:00

When coaching sports, executing a play can be rather complex with interrelated situational options involving both rules-based and opportunistic options that are very dynamic. Once you have diagramed the play and the team has really learned it, the result is all the players doing the right thing when the coach gives a single command. When the team doesn’t learn the play in a game there is no time to explain how each player needs to respond specifically to a given situation. Which results in the meaningless rants of coaches: “Move your feet!”, “Reverse it!”, “See the floor!”, “GO!” which taken at face value are not very instructional… but they make coaches sound wise, or at the very least make the coaches feel like they are contributing.

GIS data sets can be huge, CAD files can be big. Sometimes big gets to be too big. ArcGIS is designed to accommodate large datasets by managing data from the source in ways that it doesn’t have to load all the data into memory while also employing database science to manage large queries and analysis. The drafting environments of AutoCAD and Microstation employ high-end graphics technology that promotes fast drawing of large datasets, but was never designed for large scale data management. Traditionally the CAD solution is to break up files into vertical or horizontal tiles that can be combined together by reference or to be viewed individually. Within the context of mapping these might be vertical tiles where different drawings are stacked on top of one another based on their content discipline. For example a layer of electrical distribution data, another drawing which contains the parcel and street data, another for water, sewer etc…

Another method of tiling is by geographic zone. Horizontal tiles include all of the data in each tile, but multiple tiles are used to cover a geographic area. This form of tiling also supports the idea of pages in a map book, or districts, zones or other arbitrary or gridded system of breaking up the map. These grids may be to distribute responsibility, or they may be based on, ownership or other geographic boundaries. When moving CAD data from a gridded tiling system into ArcGIS tools like APPEND and MERGE are common tools to create a seamless map.

To recreate the tiling systems of CAD, the EXPORT TO CAD tool can be used to generate multiple files from a single GIS data set. The key is to include a field in the data sets feature attribute table called DocPath. Within this field you can populate each feature’s DocPath value to control which Microstation or AutoCAD file the data should be exported to.

First you will create a polygon grid that represents the geographic boundaries of what would be each CAD file. Then populate each polygon with a value in a field called DocPath that represents each CAD file name. Then I use that grid to perform a spatial join or an overlay function and maybe the CALCULATE tool to include the CAD DocPath on each feature I intend to export. I then invoke the EXPORT TO CAD tool. Be sure to leave the Ignore Paths In Tables option of the EXPORT TO CAD tool unchecked because this is what this option is for.

Then MOVE YOUR FEET! :)

ArcGIS for AutoCAD Query Tool

2009-10-09T11:15:00.000-07:00

I spent last weekend installing a laminate floor in a small room off my kitchen. This was the third phase of my flooring project that has been spread out over a few years. The first being the living room, then the kitchen. In the previous two phases I pretty much did all the work myself. For this room I enjoyed the service of my capable daughter to assist me. Not only was the effort more efficient, it was also more enjoyable because I didn’t have to spend the weekend alone in the back room, doing a thousand deep knee bends… Can someone say Advil?

In a previous post I described a way to select entities based on a simple query of ArcGIS for AutoCAD feature attributes. It was really more of a simple AutoLISP code sample than a tool…

A talented colleague has created another sample query tool that I do use as my query tool for the mapping specification for drawings data used by ArcGIS for AutoCAD. If you maintain attributes in AutoCAD using the mapping specification for drawings I recomend that you download this as your query tool.

REVIT to ArcGIS

2009-10-02T11:21:00.001-07:00

The downside of online shopping. I needed an odd sized bolt made of brass for my old sailboat and it was nowhere to be found in the local hardware stores. Easy enough to pay a little extra for shipping to save me the trouble of driving all over town. I quickly found a couple different vendors and chose the one that looked like they were really doing e-business and pushed the button and waited for the confirmation. Two phone calls and three, “ we shipped it yesterday emails”, still no bolt after over a month. Sometimes grabbing hold of the real thing and walking it to the register is the best way to go. Until e-business and boat hardware inventory systems are more interoperable… I’m off to the hardware and marine supply stores to find, and grab a 8 ½ inch quarter-twenty brass carriage bolt and matching wing nut that I can put in a bag, buy, take home and fix to my boat. …but wait I see another confirmation in my inbox.

Although, far from being an integrated system, I still have a need to get data from REVIT into ArcGIS. Here is the path I used last time I did this to create features in ArcGIS. You may find other paths to get there. Working with one DXF file exported from REVIT. The resultant AutoCAD file contained 3D entities that ArcGIS doesn’t support (Polymeshes). However, exploding them with the AutoCAD EXPLODE command did create 3D Faces that are supported by ArcGIS. From REVIT I can also export data to a 3D Studio file (.3DS). I could have used ArcGIS at this point to bring the entire 3DS file in as single 3D symbol in ArcScene or ArcGlobe, but I wanted to get the individual building parts as separate multipatch features. I imported the .3DS file into plain AutoCAD, which generates 3D face entities directly, the type of 3D CAD entities ArcGIS does support as multipatch features. The resultant AutoCAD file could then be used in ArcGIS.

Yet another option if you are confronted with AutoCAD SOLIDS entities exported from REVIT is to use the AutoCAD 3DSOUT command to export the resultant AutoCAD SOLIDS out of AutoCAD into a .3DS file and then import them back in. The result again is 3DFace entities. (If your version of AutoCAD doesn't have the 3DSOUT command, check here.)

To make the drawings even more usable I created separate muiltipatch feature classes using ArcGIS for AutoCAD for each different building part that were easily destinquished based on their AutoCAD Layer. Now when I add the data from either of the two AutoCAD files in ArcGIS I get 3D multipatch feature layers that correspond to the different building parts. I can also use the existing CAD georeferencing tools of ArcMap to position my building in geographic space, and migrate the data into a geodatabase if needed.

Autodesk Object Data Converter

2009-09-28T08:34:00.000-07:00

I just bought a sunfish sailboat. Arguably the most successful sailboat design, with over 500,000 made. This sailboat is easy to sail and has pretty good performance. My boat is one of the old ones, 1965. Several design changes over the decades have improved the design's performance. Better, rudder and centerboard shapes and materials, and a kick-up rudder feature that allows for easier beach launching are some of the more notable improvements. Its upstart cousin the Laser is faster… but not as easy to sail. Although both are touted as being “car-toppable”, both are still a little more than I want to manage by myself from my garage to the water and back without a trailer.

I have been on a quest to design a sailboat, toy, machine or thing that is fast, comfortable, simple to sail, and easy to transport by one person. I’m currently working on my 11th significant prototype concept of such a boat… I bought the sunfish because I’d actually like to sail something now!

I have some drawings that were created by someone else in Autodesk Map 3D that I need to use in ArcGIS. I have Autodesk Map 3D and could use it to convert the Object Data to Shapefiles to make the drawings more usable by ArcGIS, but a colleague has just put together an Autodesk Map 3D converter that I can run in conjunction with Autodesk Map 3D that keeps the data inside the AutoCAD file. This tool generates attributed AutoCAD drawings according to the mapping specification for drawings that I can understand and that are readily usable by ArcGIS for AutoCAD and ArcGIS desktop.

I had to spend some time in my garage retrofitting a little utility trailer to accommodate the sunfish, next weekend I will be sailing!

Getting In Shape

2009-09-25T11:30:00.001-07:00

As a volunteer assistant high school basketball coach and former athlete myself, I understand the value of off season training. Getting in game-ready shape is much different than just general physical fitness. I work out at the gym sporadically. Yesterday I played a game of basketball with the high-schoolers and quickly realized that my two mile jog twice a week was not going to take me many times up and down the floor at the pace they were running!

During the season, even as a coach I still get anxious before each game. I get transported back to the feeling I had as a player… Do I have my shoes and uniform …my sweatbands? Do I feel ready to run and jump,... ya know my knee is kind of stiff? Then I realize the only physical exertion that will be required of me is to occasionally leap off the bench and shout at the referees… respectfully of course!

Working with ESRI Shapefiles as an intermediate exchange between AutoCAD and ArcGIS is one way to move data back and forth between ArcGIS and AutoCAD. It requires that you have a way to read and write Shapefile within AutoCAD. You may have an existing routine that you jog through to make this happen.

I think people are just now coming to realize that with ESRI’s mapping specification for drawings the AutoCAD .DWG file itself is a better intermediate file for sharing data between AutoCAD and ArcGIS. It handles attribution on Points, Lines, Polygons, 3D features and Annotation. Annotation, curves and splines are supported where as in Shapefiles they are not. With the free ArcGIS for AutoCAD application there is also no need to buy any software to support the exchange of data between ArcGIS and AutoCAD.

I'm learning to sit down, relax and enjoy the game.

Selecting by Attributes in ArcGIS for AutoCAD

2009-08-03T08:51:00.000-07:00

It probably isn’t too convincing from my blog picture, but I look just enough like NBA all-star Dirk Newitzki in-person that I am frequently mistaken for him in airports, hotels and restaurants. It’s a dubious honor to simply look like someone famous, since in the end everyone is disappointed when they learn I am just me.

At a food court in San Antonio I was unable to convince a 10 year old “fan” that I wasn’t Dirk, and he forced me to sign an autograph. I have posed for a number of photos with strangers, who didn’t care if I was him or not, they just wanted to say he/I was there in the picture.

My brother-from-another-mother is 6 inches taller and shoots better free throws than me. These are just a couple of the attributes that distinguish us one from another.

Here is an AutoLISP routine that selects features by feature-attribute values in ArcGIS for AutoCAD. It uses a combination of standard AutoLISP and the ArcGIS for AutoCAD AutoLISP API. It has a simple command line interface that allows me to click through the schema of feature classes in my drawing to build a simple equality-query for the selected feature class.
(ie This = That)

You can use this AutoLISP file, as is… if it works for you, or you can use it as an example of how to build your own query tool that could make more sophisticated comparisons.

The AutoLISP code snippet below is that part that does the work… Look here for the complete AutoLISP routine that includes the command line interface.…

;Select All The Entities In the Target FC
(esri_SelectFC TargetFC)
(setq ss (ssget "P"))

(setq NextEntity 0)
;Create New Empty Selection Set
(setq newSS (ssadd))
(setq SelectionCount 0)

;Check each entity in the selected set of features
(while (setq ent (ssname ss NextEntity))

;Use the ArcGIS for AutoCAD routine to get the MSD attribute values
(if (setq ValuePair (esri_GetAttribute ent TargetField))
(progn
(setq EntityValue (cdr ValuePair))

;Compare to this entity’s MSD Attribute Value to the Target Search
Value
(if (= SearchValue EntityValue)
(progn
(setq newSS (ssadd ent newSS))
(setq SelectionCount
(+
SelectionCount 1))
)
)

)
)
(setq NextEntity (+ NextEntity 1))
);End While Entities

;Set/Grip Selection Set
(setq ss (sssetfirst nil newSS))

ESRI User Conference 2009

2009-07-20T12:20:00.000-07:00

Walking out the back door of this year’s ESRI user conference the BMW/Oracle sailing team’s trimaran was prominently positioned to steal my gaze. An amazing display of engineering and design… wow. It really impressed me with its elegant lines and high tech equipment. Looking at it right in front of me, my mind struggled to understand how huge this boat really is. Rather than accept how big it was my mind tried to force me to see the crew on the trampolines and hoisted up working on the mast as Lilliputians (tiny people). The man suspended on a boson’s seat rocking in the wind on the top of that 150+ foot mast was normal sized! The people on the sailing team were tuning that machine to make it work for them. They were preparing to set out into the ocean to battle the wind, weather, waves and the competition. People design, build and endeavor to do some truly amazing things!

It was great to meet many of you in San Diego this year. You provided us with a wealth of feedback that will really make a difference in the direction and priorities of GIS and CAD interoperability development at ESRI. I hope that you also were able to use the information we shared to make a positive difference in your work. Spending a week with people like you and hearing what you accomplish and endeavor to create is an awesome thing to experience.

ArcGIS Server Maps in Microstation: Easy as Pie

2009-06-29T13:36:00.001-07:00

I frequently borrow this device from a neighbor of mine (pictured here), which peels, slices and cores apples. It reinforces my idea that in the design of anything there must be more simple and effective solution just waiting to be discovered. As an amature sailboat designer I am haunted by this contraption as an example of what “could be”, because to me it does exactly what I want to do to an apple for making pie or cobbler. This device exceeds my expectations and even delights me when I use it. This device is not new; it is just new to me.

Something that is not new, but is relatively new to me is the use of ArcGIS Server maps served via WMS in Microstation. Microstation has had the ability to display WMS maps served by ArcGIS Server and other WMS sources for a while now, however with Microstation 8i this functionality includes a user interface in core Microstation that makes it easy to incorporate ArcGIS Server maps into my Microstation drawings.

WMS capabilities are just a checkbox option when publishing maps to ArcGIS Server. After creating maps in ArcGIS desktop, now I personally have a reason to check the WMS service checkbox when publishing my maps to ArcGIS Server. The same maps that I can use in ArcGIS for AutoCAD in the form of a Map Service are also available to me in Microstation as a WMS Service using the same ArcGIS Server.

The apple cobbler my daughter and I made last night tasted good and was fun to make.

Coordinate Systems in ArcGIS for AutoCAD; Is it morning already?

2009-06-10T13:09:00.000-07:00

Traveling from the West Coast to the East Coast has its challenges for business. On my last trip I shared a hotel room with an associate at a large conference; My colleague, tired after a long day, was looking to get to sleep at 10:00 pm, which was 7:00pm my time. My 5 year old back home, wasn’t going to bed for another hour. My colleague then announces he would be getting up at 5:00 am (booyah!) and was asking if he would have a conflict with me getting ready in the morning. Quick calculation in my head… that’s 2:00am!

The Earth is round, so even though we may have an accurate measurement that same measurement has a geographic relevance for a particular place. The watches on both of our wrists were accurately measuring the time in our zone. Trouble was I was out of my zone.

For many CAD related efforts I may be entering coordinates accurately in my zone, be it state plane or UTM or the alike. However, without some means to identify which zone I am in, or more basically what coordinate system my coordinates are depicting, when I am outside that zone things don’t line up.

In ArcGIS for AutoCAD you can identify which coordinate system you are in so that map services from other coordinates systems will automatically line up in the right locations. Likewise when the drawing is added to ArcGIS software it will also line up. By default ArcGIS for AutoCAD will assume that if you are adding a map service within an AutoCAD file without a coordinate system defined you will want your drawing to have same coordinate system as the map service. This may not be true; therefore you will want to select your coordinate system from a list of some 4000 coordinates systems that ship with ArcGIS for AutoCAD first. If your AutoCAD file has a coordinate system definition in an external .PRJ file, ArcGIS for AutoCAD can import that .PRJ file and store it inside the CAD file according to the Mapping Specification for Drawings.

For Microstation files and AutoCAD files not used in ArcGIS for AutoCAD you would copy a .PRJ file of the appropriate coordinates system in the same directory old-school.

Optimizing ArcGIS Server

2009-05-15T13:55:00.000-07:00

One of my hobbies is experimental sailboat design. And, with anything worth designing the challenges are circular and interconnected; weight, drag, stability, complexity, reliability, speed, performance. Optimization is the usually the balance of these sometimes diametrically apposed factors. If it’s light weight, it may not be reliable, or stable. If it’s stable it may not be fast or light. If it’s fast it may be too complex, unstable and unreliable. The reward in exploring a design is when I find that overlooked and elusive idea that truly can overcome the previous limitations and provide an uncompromised optimization. A solution where I can do something I could not do before; faster, lighter, stronger, simpler and better.

Although most of the things that make published map documents fast and efficient Map Services are likewise good for ArcGIS for AutoCAD, there are a couple things that ArcGIS Server IT managers should consider that are specific to ArcGIS for AutoCAD users. Technically, ArcGIS for AutoCAD uses the ExportMapImage functionality of ArcGIS Server to interact with map services.

Therefore the first order of server business for ArcGIS for AutoCAD is to ensure I have not disabled the ExportMapImage functionality on my map server. Secondly ArcGIS for AutoCAD needs an ArcGIS Server geometry service to project the coordinates of a cached map services if they are different than the coordinate system of the AutoCAD drawing. I do not need a geometry service if both the cached map service and the drawing are in the same coordinate system or when the map service is generated dynamically. ArcGIS for AutoCAD will look for the geometry service on the same server as the map and if it doesn’t find one it looks elsewhere on the internet. If a geometry service is enabled on my map server projecting cached maps for ArcGIS for AutoCAD is faster, if needed.

Better yet, to avoid problems with grainy maps caused by excessive scaling, or the performance hit for re-projecting maps, it’s a good idea to publish my map service in a coordinate system AutoCAD users are likely to be viewing the map. I may have casual mapping users who can view the map service in a geographic coordinate system since they really don’t care what the coordinates are, but generally AutoCAD users are working projected coordinates, like State Plane or UTM. If I expect I will have ArcGIS for AutoCAD users I might consider publishing maps in their commonly used coordinate systems.

Although caching the maps on my map server is a good way to speed things up for most ArcGIS map service viewing applications, it is not necessarily faster for ArcGIS for AutoCAD which still requires that a map image be created, and because of the threshold of discrete scales being set for cashed maps, the quality of the map image could be better if the map service was left to be generated dynamically.

Some of these optimization settings may be at odds with other ArcGIS Server best practices. Both are valid, I might consider creating two different map services, one for ArcGIS for AutoCAD to use and another for general users if I notice performance, or image quality issues due to projections. In most cases the differences are minor, but in combination, and with a large number of users it could become significant.

Editing In ArcGIS for AutoCAD?

2009-05-08T11:30:00.000-07:00

I have planted a vegetable garden. I don’t expect it will save me much money on food, but I really enjoy the idea of it. The best places in my yard for growing things are either covered by structures, concrete or trees. To create some more space and to thwart the plans of bugs and weeds, I’ve decided to plant my garden in pots on a terraced rolling cart. It’s like the produce stand in the picture, accept it has bins of plants from which I hope to pick fruits and vegetables.

This may sound obvious, but one thing I’ve learned from past agricultural experiments is that it is best to plant things that I actually like to eat rather than things that are just easy to grow! And it is nice to get plants that can keep producing over time rather than all at once.

If I want to allow someone to use AutoCAD to edit data I have in ArcGIS I can give them an AutoCAD copy of a sub-set of the GIS data using the EXPORT TO CAD tool. Before I export the GIS data I can flag it with a unique code of my own creation. This transaction flag can be nothing more than an integer in a field I call “transaction” or a text field. I like to create a text field, and then use the now( ) expression with the ArcGIS CALCULATE tool to create a time stamp string as my transaction code. This is probably something I should automate using a geoprocessing model; select stuff, ADD FIELD, CALCULATE, etc… EXPORT TO CAD.

A feature class will be created in the AutoCAD drawing according to the mapping specification for drawings, along with the attribute schema for the data.

TIP: I want to make sure to only export a selected set of features to avoid pushing thousands of features back and forth that I have no intention of changing. If I want more data for geographic context, I can publish a map service of the same GIS data with ArcGIS Server. I then use ArcGIS for AutoCAD’s ability to use map services to see the full basemap.

Using the attribute editing tools of ArcGIS for AutoCAD and the AutoCAD graphics engine I make edits to my copy of the geometry and attributes of the exported GIS data. If I trust the edits made in AutoCAD and I am confident that ArcGIS can see the appropriate data in the AutoCAD feature class, I can use those changes to update my GIS data. I want any features that are added, modified or deleted to be updated in the geodatabase appropriately.

Now assume that I really really want the changes I made in the AutoCAD file to replace the existing data flagged by my transaction code and still unmodified in the geodatabase. I select my flagged features with my transaction code in the geodatabase, and DELETE them. I use the modified AutoCAD file to replace the data involved in the transaction with the APPEND tool. New features will be added, modified features will be replaced and deleted feature will not be replaced, and therefore deleted.

This rather crude form of editing should be thoroughly tested in each environment and then only performed on a copy of the production data that is then verified for quality control, before changes are accepted. In this workflow I must also accept the fact that the object identifiers will be changed on all of the features in the transaction including objects that didn’t change, since in this version of the workflow everything you exported was flagged as part of the transaction.

If someone else edits the same data that I intend to be editing in AutoCAD, their edits might be overwritten by mine, or if my transaction flags become out of sync or invalid the workflow could be compromised. It is up to me to manage how transactions like this are flagged and processed. I must clean up after myself and guard the state of the database during transactions. Additional consideration would need to be given for the effects of editing features involved topologies, or networks. The bottom line for this workflow is that I am responsible for everything that happens to the data, there are no built-in safeguards.

On my produce cart now are: blackberries, raspberries, cucumbers, eggplant, carrots, onions, squash and tomatoes, in the fall, strawberries, beans and spinach will be likely additions. I’m making frequent trips to my produce stand for tending, and watering. I will automate the watering with a drip system hooked up to my lawn sprinklers.

I look forward to the harvesting.

Industry Specific GIS Data Models in AutoCAD

2009-04-30T10:55:00.000-07:00

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

2009-04-22T12:26:00.000-07:00

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

2009-04-10T10:03:00.000-07:00

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.

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.
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.
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.
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.
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.
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.
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.
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.
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

2009-04-09T11:15:00.000-07:00

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

One More Time Around the Block

2009-04-03T10:59:00.000-07:00

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

2009-04-02T12:05:00.001-07:00

“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.

MSD: Blocks and Blocking Out?

2009-03-27T10:41:00.000-07:00

We’re in the thick of the 2009 March Gladness basketball tournament the equivalent of the State finals for California Home School Basketball, where the lady warriors will be going up against their out of town rivals in the finals if all goes as planned. This is the end of the season and rebounding is going to be our focus. There may be many coaches that disagree with me, but my philosophy on rebounding is that the mysterious act of “blocking out” that eludes many players is nothing more than a continuation of the offensive and defensive flow. The offensive player shouldn’t “block out” 15 feet from the basket anymore than they should post up 15 feet from the basket. Likewise the defensive player needs to deny a cutter to the ball coming off the rim in the same manner they would defending a pass.

Before the Mapping Specification for Drawings the best method for attributing AutoCAD files for use in ArcGIS was to use block attributes for point features. There was really no go way to maintain feature attributes on lines and polygons features. Using blocks with attributes is still a good way to create point features for ArcGIS especially when you are organizing them into MSD feature classes. The block attributes of blocks in MSD features classes are still recognized by ArcGIS like they have been. The question arises when should I use MSD attributes, and when should I continue to use block attributes on POINT features.

The answer is, it depends. MSD attributes are not displayed visually as labels in AutoCAD (this is actually why I did the experiment of using ArcGIS Server Map Services to do thematic mapping on AutoCAD files.) So if you want the attributes to be a form of annotation, blocks with attributes are the way to go. MSD attributes on points have the advantage that they are managed like other attributes according to the mapping specification and can be typed. That is to say they can be INTEGERS, or REALS not just TEXT. All AutoCAD block attributes are of type TEXT. In the future the MSD attributes will likely contain other valuable functionality such as domain constraints.

Good basketball players instinctively block out, and crash the boards for rebounds, teaching players to suddenly block out when a shot goes up as a separate act is rarely understood or successful, because if players can’t anticipate a scoring opportunity offensively or defend their opponent, they are just going to stare at the ball as it bounces mysteriously to another player time after time despite their frustrated efforts.

Controlling ArcGIS Map Services with AutoLISP

2009-03-25T10:56:00.000-07:00

I’m sitting here at the 2009 ESRI developer summit in Palm Springs. Everyone here is thinking about how to customize ESRI software to do really extraordinary things. I thought it would be a good time to share a little AutoLISP routine that I wrote that manipulates ArcGIS for AutoCAD Map Services to create higher resolution images over a larger area than the current view, as disconnected raster references.

This sample AutoLISP uses ArcGIS for AutoCAD Map Services and creates a mosaic/array of resultant images disconnected as AutoCAD raster references. This sample AutoLISP routine uses a comboination of ArcGIS for AutoCAD commands, ArcGIS for AutoCAD API AutoLISP functions and standard AutoCAD AutoLISP routines.

To use it copy the lisp routine to some location recognized by AutoCAD and load the file. Zoom into the lower left hand corner of an area you want to cover with Raster Reference images. And enter the ESRIMapMosaic command at the command prompt and answer the prompts. The resultant .PNG files will be automatically named after the map service in the same directory as the working drawing file. As with all samples you are encouraged to further customize it to better suit your working environment.

Because ArcGIS for AutoCAD uses the current AutoCAD display view extents to determine the view scale for maps generated by ArcGIS server, to get a higher resolution over a larger area you can use this AutoLISP routine to bring the images local to your desktop. Although they are converted to static .PNG Images, you might find value for the higher resolution images as a backdrop. The effect is laying down a mosaic of an area built from tightly zoomed tiles of a higher resolution than is displayed when you rely on a single Map Service image to cover the same area.

Here is the file on ArcScripts: MapMosiac.lsp.

Demo of ArcGIS for AutoCAD

2009-03-24T14:33:00.000-07:00

I Just got back from the homeschool basketball national championships where my daughter’s team finished 24th. They played hard and we had some close games along with some minor injuries. Overall it was a great experience.

With our limited traveling contingent we did not have enough resources to film and take stats for the game. The solution, we recorded the game and took stats by watching the film afterward. Taking stats from the film has obvious benefits over one person taking stats during the game in that you can watch the recording over and over again and you can rewind it to see who really did what. Good plan except in the first filmed game we ran out of room on the camera and missed part of the exciting 4th quarter and our failed comeback attempt that left us 2 points behind at the buzzer. …oh well we’ll get’um next year.

Here is a video overview of the ArcGIS for AutoCAD application updated for the new features of build 200.

AutoCAD Layers to ArcGIS Feature Classes

2009-03-09T12:28:00.000-07:00

Like the Mobius strip, with a little twist what used to have two sides now has one. For those who already use AutoCAD layers as a means to define GIS layers, an ArcGIS for AutoCAD AutoLISP routine can make short work of defining your CAD Standards as GIS feature classes according to the mapping specification for drawings.

The ArcGIS for AutoCAD AutoLISP routine (ESRI_LayerToFC) is a short cut to defining GIS features from your existing drawings. It will make feature classes for each layer containing possible GIS features. If your drawings are primarily organized by Layers this might be a helpful tool to make short work of defining your feature classes in ArcGIS for AutoCAD.

Try typing (ESRI_LayerToFC) at the command prompt of AutoCAD with ArcGIS for AutoCAD loaded and see it work. It is an unsupported sample routine, but it seems useful to me.

To Serve CAD

2009-03-05T10:23:00.000-08:00

Now and then I come across something that is for lack of a better description just kind of cool. I am not sure if it is practical. Just because you can do something doesn’t necessarily mean you should do something. With that disclaimer… let me share with you something cool. Stay with me because this is a little bit “out there”.

I have AutoCAD, ArcGIS Desktop, ArcGIS Server, and ArcGIS for AutoCAD on my laptop. Doesn’t everyone? See the sign post up ahead…? In the twilight zone everyone does. (My apologies to those reading this in another culture and language, and not familiar with the obscure TV references.)

ArcGIS desktop reads AutoCAD and Microstation files directly. If my AutoCAD file contains feature classes according to the mapping specification for drawings, then I can use those feature classes directly and without conversion as layers in an ArcMap map. I can symbolize the resultant features thematically according to the user defined values that they hold. I can color polygons based off of specific values, or vary the thickness of lines based on a range of attribute values, or use different point symbols… etc. I can also use the attribute values to create text labels that ArcMap knows how to place nicely.

I can serve ArcMap maps that I create as a map services using ArcGIS Server. I can use ArcGIS for AutoCAD to consume map services from ArcGIS Server including maps that reference AutoCAD drawings. In ArcGIS for AutoCAD I can edit AutoCAD entities as well as modify entities according to the mapping specification for drawings. Now it starts to get interesting.

ArcGIS Server map services can be cached or they can be dynamic. Dynamic map services are drawn by ArcGIS Server directly from the data referenced by the map document that is being served. If I open the AutoCAD drawing with ArcGIS for AutoCAD that is referenced by the ArcGIS map document, that is in turn being served by ArcGIS Server, and I use ArcGIS for AutoCAD to connect to that Map Service of the AutoCAD file that I am in… stay with me. ...Then when I make a change to the AutoCAD drawing, such as changing a feature class attribute and save the file and refresh the map service, then I see the map that is thematically drawn by ArcGIS Server which is based on the features and user defined attributes of the AutoCAD entities from the AutoCAD drawing that I am in! ...Whew!

Ok, I’ll wait while you re-read the paragraph above… So, I can use ArcGIS Server to do thematic mapping of my AutoCAD data via a map service while I’m in the same AutoCAD file as long as I save the file before I refresh the map service, and as long as ArcGIS Server and ArcGIS for AutoCAD have access to the same AutoCAD file, and the schema of the AutoCAD file doesn’t change. Granted, this is an extreme use of ArcGIS Server, but it is, I think, an interesting exploration of GIS and CAD interoperability, pieces of which you may find useful.

In light of this blog post the roasted vegetarian from the previous post is even more disturbing.

AutoCAD files as ArcGIS Electronic Submittals

2009-02-27T10:23:00.000-08:00

Roasted vegetables or roasted vegetarian?! I was a little taken aback by my first glance at these conference lunch options shown in the unaltered picture above. I think I know what they meant? Subtle difference in words, big difference in meaning. The two words alone are ok, but together they are troubling. (I had the turkey.)

In dealing with the interpretation of AutoCAD data as ArcGIS content it is always better to avoid ambiguities and possible double-meaning through incomplete information or unguided interpretation. In ArcGIS for AutoCAD build 200 you can now specify how your AutoCAD data will be interpreted by ArcGIS. By default AutoCAD files In ArcMap are filtered as feature classes based on their geometric type. Now with ArcGIS for AutoCAD and the Mapping Specification for Drawings, I can specify criteria for additional named feature classes in my AutoCAD drawings. As a bonus any object, not just AutoCAD blocks can hold user defined attributes. This is accomplished with standard graphic and non-graphic entities in a plain AutoCAD drawing and tools included in the new free ArcGIS for AutoCAD application.

Using ArcGIS for AutoCAD to define how my existing CAD standards should be interpreted as GIS layers in ArcGIS is a great way for me to create ArcGIS data using my existing CAD standards. I can define the filter criteria for my feature classes based on the AutoCAD entity properties, the same AutoCAD entity properties of Color, Layer, Line Style etc… that I am using to define my CAD standards. I can for example include multiple AutoCAD layers to build a single GIS feature layer, or be very specific about the Color or Line Style of entities that would qualify as GIS feature for a particular GIS interpretation of my AutoCAD file.

Used in combination, GIS submittal standards can be honored using my existing CAD standards. By defining feature classes in my AutoCAD drawing using ArcGIS for AutoCAD I can follow my existing CAD standards while at the same time building GIS data. This is also great for my consultants outside my organization because they have their own CAD standards, but I want them to create specific GIS layers for me. With the Mapping Specification for Drawings they can correlate their CAD standards one time to align themselves with my GIS requirements and then use the resultant feature layer definitions as part of their template drawings, or import the definitions from the one drawing into any of their new or existing drawings. The consultant can follow any CAD standard they want and still be able to provide me with an AutoCAD file that ArcGIS will understand as having particular ArcGIS feature classes with the desired tabular attributes according to my required GIS schema.