Friday, April 18, 2008

3D City Building Case Study

While high-fidelity 3D city models have been around for 10+ years, they have been getting a lot of attention in recent years with the advent of Google Earth and Virtual Earth. I've touched a little bit on 3D building extraction and texturing in a previous post, but recently came across an excellent case study from Magnasoft entitled "Build Virtual Cities to Plan Real Cities".

The case study provides an overview of start to finish textured city construction. The main input data consists of stereo pairs, and the software involved includes LPS, MicroStation, and ArcGIS. The final products go well beyond just buildings: they also include roads, tree canopies, water bodies, electric poles, walls, and fences. You can see from the stereo feature compilation screen shot (on part 5) that complex building structures can be modeled in high detail.

Just to explain the process in a bit more detail: MicroStation is important because LPS' main 3D feature extraction application, PRO600, is an MDL application that hooks in the LPS stereo viewer and allows users to extract 3D objects in stereo within the MicroStation environment. After the building intelligence is added in ArcGIS, the models are brought into Stereo Analyst for IMAGINE (another 3D extraction tool, which is an add-on to ERDAS IMAGINE), where a feature called the Texel Mapper can be used to automatically texture the buildings from the "block" of aerial photographs. I'll expand more on this process in a future post...

No comments: