Responces to the bullet points in order:
- Right now we're defining localities as counties and cities. Two Marysville hopefully would have different zip codes or some other way to tell them apart.
- We're not really looking for street maps. We want to display membership changes of our local groups. On the local level we want to be able to display membership by zip. I hope this application will have other uses beyond this.
- I haven't come across voting software that seems useful yet. We wouldn't mind using the voting precint as the basic unit. Even if there was something, I'd rather 'roll my own' since this seems like an interesting project to me.
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A word of caution - ZIP codes are not meant for mapping - they are meant for delivering mail. You're better off geocoding with FIPS codes. You can check out Census Bureau mapping resources at http://www.census.gov/geo/www
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Take a look at geocoder.us for some great geocoding in action.
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For geocoding / user mapping, it's worth looking at:
Geo::TigerLine
Geo::Coder::US ( and http://geocoder.us )
http://civicspacelabs.org/zipcodedb/
for shape drawing and projection, check out:
Geo::GDAL
Geo::Shapelib (which has a much nicer API than Geo::Shapefile)
UMN MapServer rocks, and talks to free GIS backends like PostGIS. GRASS walks all over ESRI; http://freegis.org/ hopefully suggests that you have no need to buy ESRI products.
xoxo
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Here here! I've mentioned many a time in the CB that zip codes are (not necessarily contiguous) polylines in 3 space,
not polygons. ZCTAs are also usable for this kid of thing --
Zip Code Tabulation Areas are the Census Bureau's solution to the hairy nature of zip codes. Other census ploygons such
as block groups are good too.
--
I'm not belgian but I play one on TV.
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