The Crumbling Wall Between CAD & GIS

  Pete Kelsey endeavors to convince readers that it is not only perfectly safe to integrate CAD & GIS, but it is relatively simple. I think it is a fair statement to say that at long last the wall dividing the CAD and GIS communities has crumbled. You have probably noticed many of the trade magazines are devoting articles with titles like “Bridging the Gap between CAD and GIS,” “GIS for Surveyors,” and “Integrating CAD & GIS.” In this article I will endeavor to convince you that the dark ages, where only those early adopters who dwell out on the bleeding edge dare to tread, is over. It is not only perfectly safe to integrate the two technologies but it is relatively simple. If you don’t begin these efforts soon you may find that the folks who have are leaving you far behind. Looking Back Historically the CAD and GIS shops of a state, local or federal agency have occupied the same building but might as well have been on different planets. The CAD techs all assumed the GIS techs were pompous, well educated geeks who always seemed to get the lion’s share of the budget for hardware, software and peripherals. The GIS techs on the other hand assumed that the CAD techs were all young, high school grads who listen to loud music and who can’t spell GIS. These rather ridiculous stereotypes kept the two camps from exploring the other’s domain for years, decades actually. So what prompted members of each faction to peer over the wall? Was there a defining moment that prompted this historic event? Some would say it happened out of necessity. In a post 9/11 world the demand for georeferenced, survey grade maps with attached databases and attributes is critical. Others would say that Google™ Earth opened the general public’s eye to Web-based, user friendly GIS. Still others might say that to maintain an optimized edge in the industry, better ways of sharing data simply must be explored and implemented. I believe each argument is absolutely true. So why is this article and so many before it devoted to this subject? The answer is because the wall is coming down and, like it or not, its collapse cannot be stopped. I say, it can’t come down fast enough. Existing Processes In general a civil engineering map, drawing or project begins its life in the hands of surveyors and photogrammetrists. This phase is typically referred to as the data acquisition phase. Data is gathered combined, georeferenced, modeled and validated. Primarily the tools used in this phase are CAD related. However, a growing trend in this phase is to access the vast amount of GIS data available on the Web. While not all of this data is survey grade it can and does present significant value to the CAD folks. This data has significant value with respect to pre-design site analysis. What sort of terrain exists on the site and what kinds of challenges might that terrain present the surveyors and/or engineers. Radio coverage for GPS equipment, floodplain information, and existing survey control to tie into, are just a few of the kinds of data that are widely available on the Web. Surprisingly few CAD folks are aware that their applications can import and export a plethora of industry standard CAD, GIS, database and image formats. In some cases you might be able to locate all the data you require on the Web and save the expense of sending crews out into the field at all. I’m not making this up. This is just an example of what lies on the other side of that wall we’ve been staring at for so long. The resulting models, yes models, and their associated data then typically move to a civil engineer and his/her staff whose task is the design phase. The tools involved in these steps are typically CAD based which means that the resulting data is inherently accurate. This level of accuracy is typically referred to as survey grade accuracy. Moving Forward When the engineering is complete, typically the output is paper or hardcopy plans. This process is beginning to show signs of progress as well. Machine Control is an emerging trend among construction contractors and surveyors. The technology allows the models, in this case the 3D, survey grade, proposed terrain model from the engineer, to be uploaded to the properly equipped dozer or grader. By using GPS technology the machine will grade the site with minimal effort from the operator. This trend poses new challenges. The CAD folks quickly realize that machine control requires their models be georeferenced and accurate. Simply put, whatever is inputted into the grader is what will be graded. As such the terrain models must be meticulously created. Over time this new process increases the capability and efficiency of the engineering CAD folks. This emerging process also requires the savvy earth moving contractor and/or surveying shop become fluent in digital terrain modeling. That’s right, those of you in this space need to get your 3D CAD chops up to speed. Remember, I said the wall’s collapse is imminent and cannot be stopped. A final step, which is just now being adopted, involves the data handoff between the engineering, or CAD shop, and the GIS shop. I’ll take a step back and try to make my point by asking a question. If the civil engineering CAD community is generating survey grade, 3D data that includes cadastral information (the legal metes and bounds) terrain models, point data, all with associated database and/or attribute data, who should be having the Pavlovian response right about now? Correct! The GIS community. By including CAD data into the maps they create, the GIS community does not have to create data that may already exist, the accuracy of their maps will jump significantly and, when the next project comes along, the GIS data gathered by the CAD shop during the data acquisition phase will be that much more useful. In the end a new cyclic process will emerge that significantly benefits all involved. It is clear that the software developers are also embracing this trend. The CAD and GIS industries are tailoring the technology to these trends. The CAD developers are becoming more GIS capable and the GIS applications are becoming more CAD compatible. The surveying and construction industries are also involved and taking steps to facilitate the necessary interoperability. It’s a beautiful thing. It is my pleasure to report that by embracing this interoperability, or data exchange capability, the CAD and GIS communities are finally abandoning our stereotypes, stepping over the remains of the wall, enjoying marked productivity gains and quietly admitting that we should have done this long ago. Pete Kelsey, Autodesk Originally published in [acronym] magazine, Issue 3