Sep 16, 2010

GIS CAD WTF?

Our studio was broken up into groups to study an area of the city. Some groups got to study the history of the place, some focused on ethnographic and socioeconomic demographics, some groups looked at trees. One group is responsible for mapping the entire site, and is responsible for making a massive site model and also modeling the whole thing in 3D. Guess which group I'm in?

Since no one had a CAD file of the city handy, the loose idea was to trace over aerial photos. However, I thought that perhaps, in the entire history of the school, which happens to be in St.Louis, someone in the architecture program or urban planning or geography might, just might, have needed to map St.Louis. I got in contact with the top GIS (global information system) guy at the school and he directed a group of us to some very nice maps which included street edges, topography, and (praise be!) building outlines of every building in the city. This is really really cool. Since we figured we just saved a huge amount of time and energy.

Almost. There's issues with the data. The data used to map the city was done at different points in time which means that the coordinate systems they used do not exactly line up. Long story short, when we overlaid all the maps on top of each other, they didn't line up. Out of six maps, only two lined up. We spent about five hours to figure out first why they weren't lining up, and then finally how to export the data with a coordinate conversion in place. So finally at the end of the day (or around 6pm) we had a CAD file with streets, street edges, parcels, topography, and houses, all in reasonably the same spot. Except for parcels which had something odd with the data. So that was frustrating, but now we have a map that the entire class of 71 students will use as a base file.

We'll take that data and use it to build the physical wooden model and the digital 3D model, all of which, by the way, has to be done by next wednesday.

Also, by the way, Saori's mom is coming to visit from Japan this Saturday, and she'll be staying with us.

2 comments:

Andrew R said...

There should be no need to "trace over aerial photographs". If you go to Google Earth, my understanding is that you can access three-dimensional models of many buildings throughout the city.

In addition, many students and professionals have worked in the Saint Louis city context for years in CAD, so the data is there, you just need to locate someone who can provide it to you.

Do some Google Searches for information as well as PushPullBar and other online resources for CAD files.

Unknown said...

We did actually end up finding some data for the city in terms of building footprints, street curbs, topography, etc, but I will definately check out PushPullBar. Thanks for the suggestions!

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