[postgis-devel] Grid-based Landuse and attributes

[maplabs at light42.com]

in 2011 / 2012, I was lead technical implementor for a study of land 
use, jobs, housing, energy use and transportation in California, using 
a 150 meter grid. The 'grid' was a refrerence set of geometry, each 
resembling a box, in EPSG:3310. It is reference because the ID of each 
grid cell is known in the state capital GIS data, such that an urban 
planner in San Diego could refer to box ID 100, and it is the same grid 
cell as a planner in San Francisco would see. 

This project resulted in five primary result tables, covering the five 
major urban centers of California:

    http://blog.light42.com/wordpress/?p=1439

You can see an example of the SQL here, and in other posts:

    http://blog.light42.com/wordpress/?p=1489

The study has since changed contents, but continues to this day, based 
here in Berkeley

--
Brian M Hamlin
OSGeo California Chapter
blog.light42.com

On Wed, 21 May 2014 17:12:50 +0400, Alexander Korotkov  wrote:

       On Wed, May 21, 2014 at 1:02 PM, Jeremy Palmer  wrote:

         Hi PostGIS Devs,
   
  I have a daily process that I would like to optimise. The process 
includes a spatial intersects join between a small administration 
boundaries table for New Zealand that contains large geometries 
(100,000+ points per polygon) and a large dataset with small line 
strings. 
   
  The first iteration of SQL I developed for the process I used 
standard join (WHERE ST_Interesects(admin.geom, other.geom)) and it 
took 4 hours to complete. No spatial index was used. Not acceptable. 

So, your task is so-called "spatial join". We are now doing researches 
on it. It would be nice if you could share your dataset so we can do 
experiments on it. 

------
With best regards,
Alexander Korotkov. 

-------------------------

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