The phrase CAD and GIS Interoperability comes up often in the GIS industry. What exactly does it mean? Working in the GIS field for the past 25 years I have seen and experienced many changes. Today the differences between CAD and GIS are a bit blurred.
There was a time when deadlines were not much of an issue and municipal drafting sections provided manually drafted hard copy maps for their clients.
Municipal governments have come a long way from the process of manually drafting new subdivisions onto paper at specific scales and photo reducing them to fit other scales for internal recording and update purposes. Times have certainly changed. Now we have to work on changing the way we think.
Before the 1980s CAD and GIS were considered two separate applications.
The focus in the 1980s was to find the best way to shift from drafting manually on a drafting board to using CAD software on a computer. The next step was to bring high-end CAD applications into the workflow.
GIS vendors were tackling complex algorithms to merge and explore spatial features on expensive mainframes and minicomputers. Integration in these days took the form of translation, which many organizations still do today.
Semantic translation tools improve on the lowest common denominator approach to integration by providing rules-based "interpretation" of data. The challenges are similar to those involved in translating languages — in which word order, figures of speech, and context are critical aspects. The goal is to define the rules of how CAD data can be used as GIS data (or vice versa) in a consistent and reusable manner.
Figure 1: Without interoperability, data transfer between departments required conversion, either scheduled or 'on the fly', which created processing delays. Click on image to see enlarged.
Traditional CAD and GIS
- Traditional roles of CAD and GIS are evolving faster than the typical user can adapt to the changes.
- The divide between CAD and GIS is not as obvious as it used to be.
- It's the application of each technology that makes the difference in creating efficiencies for today's work processes.
- Those who use CAD in a traditional sense emphasize drawing and coordinate geometry tools (which are detailed, controlled, and site-specific).
- Those who use GIS in a traditional sense focus on mapping, data management, and geoprocessing (on a global scale).