I Can See My House!

By Gary Smith

Author's note: This is a continuation of the editorials started a few weeks ago (How Big is an Acre?, published on Sept. 7, and What is Your Excuse? published on Sept. 28). The goal is to stimulate discussion about 3D GIS, its possibilities, limitations and capabilities.

Last week I received a phone call from a person wanting to know if we carried maps of Afghanistan. As a GIS consulting firm, the phone company struggles to figure out which category to place us under in the Yellow Pages, so calls like this are not uncommon. The caller indicated that she had a son in the U.S. military about to deploy to Afghanistan. She wanted to know more about the area and to follow his travels during his deployment. Having been involved in commercial cartographic production, I was able to give her several companies to call or explore on the Web to purchase a paper map. I also suggested that she become familiar with Google Earth. While speaking with her, I launched the program and went immediately to Kabul to see how much detail was available. I was delighted to see that very good imagery was available over much of the area. With both a 2D and draped 3D view available, this proved to be an excellent option. Add the "Google Earth Community" points and more information became available. Wow! After hanging up, I patted myself on the shoulder for making such a great suggestion. I wonder if someone in Afghanistan is looking at my home town?

I suspect that most of you have taken a few minutes to show someone his/her house or area of interest using high-resolution aerial imagery. If you do so with one of the Web-based viewers like NASA's "World Wind," Microsoft's "Live Local" or Google's "Google Earth" it is usually not long before their amazement ("This is great!") is tempered by a comment that this high resolution imagery is a bit unsettling (more like "This is scary!") because it is available to everyone. When 3D content is added to the terrain-draped imagery, interest is usually heightened. Real or imagined, this feeling of insecurity is something all GIS practitioners should consider, especially as we transition to 3D. We need to step forward and manage this condition, not ignore or hide from it. 3D is coming one way or the other.

When we create 3D environments, it usually involves taking many photographs and making measurements of the buildings and landscape features we wish to model. The pictures are used to texture the buildings to provide a life-like appearance and to avoid having to draw every bit of detail. While out collecting information, we have noticed that people have become very observant. Seldom will a day go by that we are not asked, "What are you doing?" I welcome this interaction as I feel that this is important to public understanding. We also only take photographs from very public vantage points. We avoid showing back doors and windows unless they are very visible. Not showing this detail can help maintain a feeling of security, but there is a cost. The utility of the database to first responders is reduced without this information. Companies like Pictometry already provide oblique, low altitude imagery that depicts all sides of buildings, so perhaps we are being too cautious? Will a 3D GIS display with only front detail be adequate for the real estate market?

I think all of us involved in the creation of GIS data wish that information to be used in many productive ways. We are trying to be good citizens and are proud of our work. I have often thought that the 3D environment created for community planning should also benefit fire, police, public works and assessors. How about feeding into the high school driver's education simulators? Wouldn't it be great if our young people could traverse the virtual streets where they live while learning how to drive? At the risk of sounding paranoid, what does the community do when a game developer asks for the 3D GIS data? Perhaps that request will be OK, if the game to be created is a grand prix racing game. How about for use in "Grand Theft Auto" or another violent video game? In an open society, how do we provide for the proper use of our information? Please share your thoughts and suggestions.

It is widely believed that Microsoft, with its alliance with Pictometry and acquisitions of Vexcel and GeoTango, is actively working to create 3D content for its Virtual Earth development environment. Google, with its acquisition of @Last Software (makers of SketchUp) has taken a more open approach to 3D. Google is encouraging everyone to use SketchUp to help populate the globe by posting building models to its 3D Warehouse. What are the motives for Microsoft or Google to undertake this 3D assembly? They would seem to be different from what drives the traditional GIS user, but I would be very reluctant bet on that hypothesis.

Regardless of their motives, the Microsoft and Google 3D efforts are significant undertakings, but I doubt that they will meet many GIS analysis needs and may best serve to display results to large audiences. Therefore, we can all expect to be involved in the creation of the 3D environment for our area of interest. We will do this on our GIS systems. How do we do this and keep everyone happy? The first digital parcel map I created over 20 years ago concerned some landowners. Now it is never given a second thought. In fact, a digital parcel map layer is expected to be a part of a community's GIS database. Is the transition to 3D going to be any different?

The previous editorials generated a number of great comments and thoughts. Thanks to Duane Marble and Mats Elfstrï¿1⁄2m for pointing out that what we are really creating today is a 2.5D display. Carl Reed pointed out the need to accommodate the vertical datum and to establish standards. Several people questioned the need for 3D in some applications. I agree. 3D is not the answer in all cases. The 2D map will certainly live on and rightfully so. The theme that concerned me was the one that suggested people just did not have the time to learn 3D. What will it take to mitigate that feeling of time constriction? How about software developers improving and supporting 3D development tools? Have you ever asked an architect about sharing your GIS data for her new building model? We, the GIS practitioners do NOT have to do it all. We need to expand our alliances and interoperability.

Published Friday, October 13th, 2006

Written by Gary Smith

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