Thanks for the response Stephen.I will have upwards of 150,000 lines features that I will want to feed into the density. These are stored in a single table (actually will be in a CTE), and many of the lines will overlap one another. It is hard to say whether these solutions are viable as I am having a hard time visualizing the SQL. You would think that I am not the first person who has wanted to do this in PostGIS, but I haven't found example one.
On Sat, Dec 22, 2012 at 6:02 PM, Stephen Woodbridge <[email protected] > wrote: > On 12/22/2012 3:07 PM, Jeff Adams - NOAA Affiliate wrote: > >> Hi, >> >> I was wondering if anybody knew of a way to create a very simple line >> density raster. I am not interested in interpolation or clustering, >> simply how many line features pass through each pixel in the raster. I >> know how to do this with points, but am having difficulty figuring out >> how to do it with lines. Any help would be greatly appreciated... >> > > Separate from the SQL, you probably need to have a strategy for doing > this. so with a point I assume you just increment the point in the raster > for each point. So with a line we want to increment the all the raster > points along the line. Some options: > > 1. render the line into an empty raster then add that raster to your > master raster. Where add will increment by one every set raster point in > the rendered line. > > 2. segmentize the line into segments that are the size of a pixel in your > master raster and then add the midpoints of those segments to your master > raster. > > Would one of these work for you? > > -Steve > > ______________________________**_________________ > postgis-users mailing list > [email protected] > http://lists.osgeo.org/cgi-**bin/mailman/listinfo/postgis-**users<http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users> > -- Jeffrey D. Adams Contractor OAI, Inc. In support of: National Marine Fisheries Service Office of Protected Resources 1315 East West Hwy, Building SSMC3 Silver Spring, MD 20910-3282 phone: (301) 427-8434 fax: (301) 713-0376
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