Monday, June 11, 2012
I need my proprietary GIS for this hard-core geospatial analysis, right?
Bill Dollins blogged recently that he doesn't see much difference in capability between open source and proprietary geospatial tools.
I think Web/GIS developers would agree. But I'm not so sure that geospatial analysts would agree.
I agree, if we're talking about building and using map apps -- displaying points, lines, and polygons, and routine map functions like routing, thematic mapping, and interactive display of the map and underlying data.
But what about hard-core geospatial analysis? Case at hand:
I'm working on an emergency management application that estimates the age-group populations that may be affected by an emergency event. The only population and demographics data I have is census block groups. I create a buffer around the event, then clip the census block groups that intersect the buffer.
The problem is that for many of the included block groups, only a small portion lie within the event zone. So, only a fraction of the population in each of those groups should be included.
I was ready to write the function for my Python script that would calculate the percentage of the area of each block group that got clipped. If only 15% of the area got clipped, I would grab only 15% of the population counts for that block group to add to my population total.
Then I saw Esri's announcement that ArcGIS 10.1 now includes an has areal interpolation tool.
Seems like the perfect fit for what I need to do. I can create a grid of 100 x100 meter polygons and re-assign portions of the population counts to these much smaller and regularly shaped grid polygons. And save this data layer for use any time a need a more precise population estimate.
Can any open source geospatial tools do this? I admit that I don't know.
I think it would be good to do something like what Tobin Bradley did to evaluate the importance of different elements of the Google Maps API. Maybe do the same with Esri's ArcToolbox. How much of this tool set is present in open source geospatial software? How important are the missing tools?
Has anyone besides Esri done an assessment like this?