Thursday, April 10, 2008


I was tasked with creating a Google Earth file for a presentation. The main goal was to demonstrate change in enrolment from one year to the next (two years). I can't go into data specifics due to confidentiality. There were a handful of variables they wanted to show, mainly enrolment, and indigeneity (indigenous status), at two scales (cluster (similar to school district in scale), and individual school). If you try to approach this traditionally, cartographically speaking, who knows how many maps you would end up with. Some sort of bivariate or multivariate symbol would probably have to be created. With GE though, there are different possibilities. The obvious benefit is being able to show data at multiple scales using regions. This allows the presenter to zoom into specific areas of interest and as you get closer, the cluster symbols disappear and schools pop up. To show change, I used the timespan tag and GE's animation capabilities. Basically, I used the total enrolment as the altitude and animated between the two years. So you could see the rise and fall of the points in "3D." I also had the symbol set to different colors indicating positive, negative, or no change. Essentially, I took the route of "dynamic multivariate symbols" (I'm citing myself, b/c I think I just made that term up :)). This obviously wouldn't have been possible without Google Earth. Then again, this wouldn't have been possible without modern-day presentation technology.

Well, I think I'm off Google Earth for a while. I was focused pretty heavily on it for this presentation. In my spare time I'm working on a Box Shaped World tool set. The focus is mostly on tools that I need, weighing heavily on spatial statistics. I have a Ripley's K that is functioning quite well, and I think I've got a basic kernel density tool built. All the tools are built in VB.NET, for MapWindow 4.4 (and presumably 4.5 when that is released). I chose MapWindow for my project for a variety of reasons: supports .NET (the only programming language I know), has an editing environment for shapefiles (unfortunately it only supports shapefiles for vectors, but shapefiles are a universal format), extensive raster/grid support, and an apparent plan for future directions. Plus it is free! My tools will be free as well, but I don't think I'll release source code, at least not initially. I thought about sharpmap, but didn't go with it. I like sharpmap and hope it continues along its path. I didn't want to program a GIS interface, and there isn't much editing support from what I could gather. I guess (this may or may not be true) my impression is the MapWindow folk seemed to have it a little more together, but I'm not involved in the development process and I appreciate their efforts and time. Sharpmap seems to be completely volunteer based, too, where MapWindow is University based...Again, I like sharpmap and hope to use it in the future. Anyway, my tools will advance as I have time for them...

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