My initial attempt at merging the contours I got from Menlo Park, and the aerial image I snagged from Terraserver has pointed out a few weaknesses with AutoCAD, and the need, as I anticipated, to use other, more capable programs.
The first limitation is that even though both the contours and photo have coordinates associated with them, they are different coordinate systems (state plane vs. WGS-84), and not only does ACAD 2005 provide no means of converting between the two, it completely ignores any coordinates associated with raster images (GeoTIFF images or TIFF/JPEG images with a world file). I’ve manually overlaid the photo, scaling and rotating it to get it close enough to do some initial planning, and to confirm that vanilla AutoCAD isn’t the right tool for this task.
The second limitation is a great example of AutoCAD’s lack of built-in support for 3D input devices. First, since the controller’s action is grafted onto AutoCAD, every movement of the controller pollutes the command line and the undo history with its commands, and when you stop moving, the display flashes annoyingly as AutoCAD’s “real” view is updated to match.
Second, the performance of the realtime 3D viewing sufferes dramatically once the image is attached—even if I unload the image to remove it from the display and memory. Even on my 3.0 GHz Pentium 4 and GeForce FX 6500 graphics card, the slowdown was enough that I had to revert to a version of the file without the image attached to check the contour file.
The great thing about the SpaceBall is the ease with which it lets you change your perspective. I found gently twisting the drawing around in 3D allowed me to quickly find contours that had the improper elevation and fix them. Although when I needed to highlight an out of place contour and then change the view again to get a better perspective, the highlighting disappeared—also an artifact of AutoCAD not having built-in support for the SpaceBall.
Despite being Web-based—or likely because of it—the various USGS facilities for downloading digital images are painful and tedius to use. But a free mapping application makes it easier and quicker.
USAPhotoMaps, written by a retired airline pilot, lets you download images, one tile at a time, from Microsoft’s free TerraServer Web site, creating a seamless image database that you can pan and zoom with, switching between USGS quads, ancient grayscale aerial photos, and for some urban areas, brilliant high-resolution color aeral photos. Although you must install and use a separate command-line utility, you can also export any rectangular region as a JPEG image, along with a matching world file to enable georeferencing.
It may be possible to get a GeoTIFF directly from the USGS site, but it won’t be a pleasant experience.
I thought I knew the answer to this question already, but after a little more browsing on the Autodesk Web site, I’m not sure. I already know which civil engineering package from Autodesk is the one best suited towards the type of planning I want to do. I know I need 3D visualization features, terrain modeling, coordinate conversion, and raster support, but which one? It is possible that Raster Design may add enough functionality if I use GlobalMapper for the 3D format conversion, but if not, then do I select Civil 3D, Civil Design, Land Desktop, Map 3D, Envision, or perhaps even CAiCE Visual Construction?
There is no one matrix on the site that gives a potential purchaser a good idea of how these products are related to each other or work together. Clicking on “Solutions” on the home page, then “Civil Engineering & Construction”, then “Planning” and “Start Now”—a farily obvious choice—leads me to a contact form that will surely result in a bunch of product literature showing up in my mailbox, rather than a decent feature matrix or product information.
The obvious candidates for software that should be up to the job are AutoCAD 2005 and Bentley Microstation V8.
However, I already know that AutoCAD’s inability to insert geo-referenced images will necessitate the addition of Autodesk Raster Design or a switch to Autodesk Map 3D for even my most basic 2D mapping needs. And I also know that I’ll be unable to create a 3D surface from the 2D contours I have, so I’ll also be using Global Mapper for data conversion, along with GeoTIFF Examiner Pro.
Bentley’s marketing brochure for Microstation V8 indicates that it natively supports GeoTIFF, but it is also possible I’ll need to explore the MicroStation Civil Extension and MicroStation GeoGraphics extensions—or one of Bentley’s more specific civil packages—to add the capabilities I’ll want further into the project.
As a footnote, I was troubled by the configuration of Bentley’s Web server: typing “bentley.com” (all that should be necessary) didn’t work in either IE or Mozilla; I instead had to type “www.bentley.com” into both browsers in order to reach the site. It’s indeed a small nit, but forcing me to type these needless four extra characters doesn’t exactly give me a warm fuzzy feeling.
Now that I’ve got ahold of the primary data I need—the AutoCAD drawing with 2-foot contours—I can now start on the creation of maps in earnest.
The goals at this stage are basic:
- Combine the contour data and aerial photographs to create a 3D map of the park, to aid the club in determining the best location for our setup, given the terrain’s impact on RF propagation and on public access.
- Combine the contour data and aerial photographs to create a 2D map of Bayfront Park, to aid us in presenting our preferred location to the park rangers and others that have the ultimate say on what area we can use, and for publishing in 2D media.
It should be possible to position models of the equipment and vehicles easily in both the 2D and 3D models, and all of the data formats we use should use the Lat/Lon coordinate system with the WGS 84 datum, to ensure interoperability—especially with GPS equipment.
After making two different attempts in-person to convince the Menlo Park city engineer’s office to provide the PAARA/MPCDRC radio club with the 3D contours or DTM of the paper map that I had earlier obtained for the princely sum of $5, I managed to contact someone in the office that was able to get me the data I needed.
Although I was annoyed at the language barrier (I had to spell “club”—twice), the enginner on duty I was transferred to said she would check with her supervisor, but probably wouln’t get back to me for a week and a half, since the office was shutting down for a week.
I was pleasently surprised, however, when just ½ hour later I received a call back from the same engineer, saying she had found the file and would be happy to E-mail it to me. It indeed arrived a few minutes later.
Opening it in AutoCAD showed some interesting things. First, the paper map I alredy had was missing a few details I knew existed, such as the methane collection network that we of course need to protect during our set up. Turns out these are in the DWG file, just on frozen layers.
Also, although most of the contours have the correct elevation assigned to their Z value, a few contours had a bogus elevation of just 10 feet. This became apparent only when viewing the map with 3DORBIT.
We’re well into the 21st century, and it’s been almost six years since Microsoft first documented how to install drivers and applications without annoying users, in the MSDN article Best Practices: Avoid Reboots During Install. This information also appears in Windows Logo Handbook—BackOffice Requirements (see page 39), and several other locations.
Yet right now, I’m just installing an FCC database that uses ESRI’s Arc Explorer 2.0 to allow searches of commercially licensed radio and television broadcast antennas, cellular phone towers, Licensing Market boundaries, and other useful information—and it’s telling me that I must reboot before I can use the program.
Even as recently as December 2001, Microsoft described Installing Drivers and Utilities without Rebooting on Windows.
Why is it, then, that ESRI forces users to suffer this needless reboot? It is time-consuming, forces you to interrupt anything you are working on, and then restore it all when the installation is complete. This frequently happens to me just when I have a bunch of browser windows open with carefully constructed searches and search results open, and there is no good way to save the current state of such research.
So ESRI, I challenge you to fix this annoying bug. It shouldn’t take more than 2 months.
