Hi John, ArcGIS offers a similar type of analysis (summing length of lines in each raster cell) for line density. This is definitely a useful measure. Wouldn't mind if I could do both. I am looking at the density of marine vessel transits with goal of trying to see where vessel routes are concentrated. For this particular analysis, I am not really interested in the amount of any particular transit in a cell, just that it was there. I suppose the sum of line lengths can serve as a proxy, but in a perfect world, I would be able to create a raster whose values represent the number of transits. Thanks for the response and happy holidays...
On Mon, Dec 24, 2012 at 9:39 AM, John Callahan <[email protected]>wrote: > I had the same problem. I ended up using the Quantum GIS function, Sum > Line Lengths. Input can be your postgis line features. It adds up the > lengths of the portion of each line that crosses a particular grid cell. > You need to create a polygon fishnet matching your raster extent and > resolution first, then convert to raster. This might actually be a better > measure of density then counting lines. > > - John > >
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