June 09, 2002


Convex hull polygonAs J & I gear up for upgrading the Julian Charter School information system, I keep thinking about useful things to do that would lead to my learning new things. One thing that June asked for awhile back was some way to represent all the JCS students (or various subsets of them) on a map. With that in mind, I found Geocode.com, which offers to turn street addresses into latitude and longitude for you. 2,000 addresses would cost a mere $75.

Stopwatch Maps does it for $25 per thousand but has a minimum order of $150. Something to keep in mind if we ever do this for a lot of data.

Also found the FFIEC Geocoding System, a government web page that doesn't give you latlong, but does give you information about the census tract of a given address.

GeoQwest has a tool to tie spatial and time data together to create a single code. It tells you not only where but when something was.

Once the data are geocoded, I could see using PHP to graph the data onto a rectilinear projection map of the three counties and tie it to searches for subsets of the data. Alternatively, we could use Microsoft (ick!) MapPoint on the desktop.

What could we do if we geocoded the JCS database? We could organize field trips, play groups, and car pools based on where people live. We could look at the distances between a given teacher and her students and perhaps find ways to reassign students to minimize the driving. From what I've just learned, it seems that one way to calculate that might be what is called a convex hull polygon. That assumes that the area of the smallest polygon that includes all points on the map is a good approximation of the territory you have to cover.

By looking at data from the census, we could also do an analysis of what kinds of neighborhoods we're drawing from and maybe correlate it with the curriculum they use and their test results. If that's not immediately useful, I suppose, it could lead to more interesting questi.21; There's a dissertation or two waiting to be carved out of such data.


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