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As a test run, I'd like to visualize population on census blocks for a few states (New England for example). I assume that the kml to do this will be huge, when you factor in the census boundaries and population data.

How can I make my data efficient to be able to do such visualizations keeping in mind that I might extend this to having multiple census periods, and doing a time lapse combined with a flythrough?

Also note that usage of Google Earth isn't necessary. I'm open to using QGIS

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don't assume, create a network kml that will pull data on demand when requested - Geoserver can do this. docs.geoserver.org/stable/en/user/googleearth/overview.html –  Mapperz May 26 '11 at 13:46
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I did this by converting shapefiles into rasters with a large gridcell size, and then converting these rasters back to polygons, and then to KML format. This is an easy way of simplifying the data, but I think it also looks better in a visualization.

(I'm happy to share the code, though it is for ArcGIS 10).

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We're still using 9.3.1 –  dassouki May 27 '11 at 19:02
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You could generalize the boundaries and remove excess points. Fewer points = less data = more efficient. It would be less accurate, but then I get the feeling the visualization is more important than exact positional accuracy.

Or you could replace the census area polygons with a circle (max size that fits inside the boundary?). Again, if visualization is the key then it needn't be exact map boundaries that you are showing.

I like the idea of a network link, but I wonder how well it would work when doing a flythrough. Could it fetch data fast enough???

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I'd like to get away from the idea of a network link, we're not setup to doing so, and I don't think there is interest to using geoserver at the moment –  dassouki May 27 '11 at 19:03
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