An early CAD file amphibian or a GIS mammal? Dale Lutz, co-founder, Safe Software explains how the two compare, who the new kid on the mapping block is, and where his allegiance lies.
GIS and CAD are fundamentally different
GIS is more structured. It’s data management with precise specifications and schemas defined. It would be hard to go rogue and abuse it.
CAD technicians, on the other hand, can apply their artistic license and suggest how it should be used and design anything they want.
Based on the fundamental differences, data migration between the two can be a nightmare. Even if users followed CAD specifications, they probably applied them loosely. A street can be labeled as a boulevard as well as a road. They are the same thing. Once you scan a thousand CAD files, you’ll see how people just named things on the whim. During the transformation from CAD to GIS, you read the CAD file and check against a spreadsheet of what’s standard and should be allowed. Colors, line styles, levels, and layer names. Anything that doesn’t match the specs is handed over to a technician for cleaning up. In the case of our misnamed streets, once the different names you encountered are collected and put in an Excel sheet, someone can manually go through the list and group them. Doing this can reduce 800 variations of the layer names down to 30, so that the translation can take place.
Difference lies in mindset too
Rules are often interpreted and enforced differently depending on how rigorous the mindset of the users or the organization is. More recently, systems like Maximo and IBM require CAD standards as well as CAD files to conform. This opened up a new market for CAD add-on tools that enforce specifications, resulting in tighter data models. NewCAD now has certain GIS elements, a little bit like Bentley’s XFM that stores rich attribution with drawing elements such as AutoCAD map or Civil 3D, providing structure. If an organization prefers to go down the CAD route, it can do so with the help of these newer developments focusing on stricter specs.
Migration and the lack of coordinate system in CAD
A missing coordinate system is a menace, really. Even back in the days of MapInfo, people realized that not having a coordinate system at all was a problem. They relied on standards and metadata. Yes, there is always the option of tricking the local coordinate systems as everyone did early on, inspired by ESRI. A CAD file could be shifted by plopping down a coordinate system and a world file, then the feature manipulation engine (FME) would pick it up.
NewCAD is said to have a coordinate system that’s going to be written and read properly. Civil 3D and AutoCAD maps have also progressed in this regard.
Also Read: BIM vs GIS or BIM and GIS
How is CAD shaping GIS and vice versa?
You can already see a meeting in the middle of modern tools as a result of the progression in the last 15 years. Just look at ArcGIS. Sophisticated geometries are a possibility. Rich data collection that CAD technicians love and sophisticated production of drawing is already available in ArcGIS’s editing tool.
Take a look at the most recent network and utilities work that EPA EMI is doing for modeling transmission lines. It’s a powerful data model that’s deep, connected and has elements of old CAD files with a familiar look.
Indoor navigation and the new kid on the block
IMDF 4 is an indoor mapping data format that’s used by the Apple ecosystem. At the moment, it’s a maze due to the varying degree of rigor in how facilities such as shopping malls or airports collect their data. Some did it robustly with high spec and quality. Some did it in a Wild West manner. Indoor mapping and navigation are a wave that washes the causes of change. Now there is more reason to give maps a meaning other than just for the purposes of facility maintenance, and as a result, people are beginning to pay more attention.
GIS and CAD have managed to run an exclusive show as a duet, so far. With the arrival of BIM or Building Information Models, it’s going to be a stellar trio. BIM takes a drawing from CAD and attaches meaning to it to make explicit relationships. Technicians can now walk around and change lightbulbs in the right places and people can get to the emergency exit quicker.
Is one going to overtake the other in terms of importance?
Unlikely. They coexist peacefully in the geospatial realm with their new friend, BIM. BIM will produce CAD files for downstream use. Some users will prefer collecting information in CAD because they are unlikely to migrate to BIM. The letter A in CAD is not for analysis, it’s for aided. The current system lacks analytics.
GIS is the analytical toolbag in this mix. It can take the data collected in CAD or designed in BIM and lets you reason, ask hard questions and use it for analysis. What is the time that it takes to exit from each spot in this building? Can we draw diagrams or make labels on different things? Can we make heat maps of where people are going? Can we compute the most efficient routes to and from various spots?
What is the future of CAD technicians?
With so many of the latest software solutions out there that don’t require an in-depth knowledge of Geographic Information Systems and its specialist tools is it a wonder that GIS technicians and analysts are wondering what the future has in store for them? The same questions must be running through the minds of CAD technicians too.
The role of CAD technicians and experts is likely to evolve by progressing to BIM. They will be using extensions to the NewCAD system that will allow them to collect and attribute information at the same time as well as mobile data collection. A CAD technician isn’t just sitting there identifying red lines. Using plug-ins like XFM or Civil 3D with a structured data model lets them put more intelligence into the data they’re collecting. They know that it’s a red line because it’s a certain kind of road. It’s planned, and it has a surface. It’s explicit.
AutoDesk and Bentley are also moving towards online data and away from tiled files that are local which would also go hand in hand with BIM. We don’t need to store data locally anymore, as we did on AutoCAD and MicroStation, for speed of display. We’ll be using JSON, a flexible way to have as many different properties, attributes, and geometries as we want. The division between GIS, CAD, and BIM will get blurrier whether we use Bentley’s iModel 2.0, AutoDesk’s Project Quantum, or whatever it may end up being named when it becomes commercial. It’s going to take a while but watch this space. These two are where the puck is going, as Wayne Gretzky says.
