Re: [GRASS-dev] Add a cost distance measure to GRASS GIS lib

2012-03-01 Thread Moritz Lennert
On 01/03/12 20:02, Benjamin Ducke wrote: I believe we are thinking in different directions here. My idea was not about _least_ cost paths, but about replacing straight-line distance measurements with cost-based distances -- for more realism when modelling physical processes. Yes, but how to def

Re: [GRASS-dev] Speeding up v.out.ogr (again)

2012-03-01 Thread Benjamin Ducke
> > No, this is because the i-th feature does not need to have category i, > it can have any category and multiple categories. Selecting all > attributes at once for all categories is also not memory-safe for > larger vectors. > Hmm, let's say we take the smallest and largest category values in

Re: [GRASS-dev] Add a cost distance measure to GRASS GIS lib

2012-03-01 Thread Benjamin Ducke
I believe we are thinking in different directions here. My idea was not about _least_ cost paths, but about replacing straight-line distance measurements with cost-based distances -- for more realism when modelling physical processes. Just like you'd use a geodetic distance instead of eculidean in

Re: [GRASS-dev] Add a cost distance measure to GRASS GIS lib

2012-03-01 Thread Glynn Clements
Benjamin Ducke wrote: > I have been pondering this for a while and would > like to know if people on this list think the > following would be a feasible/useful addition to > GRASS (7): > > How about, in addition to the MASK raster, we'd > also allow the user to specify a COST raster? > This woul

[GRASS-dev] Re: GRASS-dev] Add a cost distance measure to GRASS GIS lib

2012-03-01 Thread Michael Barton
This sounds like a potentially interesting and valuable idea. I don't know what the 'cost' might be in terms of building this functionality into other modules. Michael On Mar 1, 2012, at 12:00 PM, wrote: > Date: Thu, 01 Mar 2012 09:27:16 +0100 > From: Benjamin Ducke > Subject: [GRASS-dev] A

Re: [GRASS-dev] Speeding up v.out.ogr (again)

2012-03-01 Thread Markus Metz
On Wed, Feb 29, 2012 at 8:23 AM, Benjamin Ducke wrote: > Dear Devs, > > A while ago, I submitted a small patch for v.out.ogr > that moves the SQL SELECT out of the mk_att() function, > so that this costly operation does not have to be > performed multiple times: > > http://lists.osgeo.org/pipermai

[GRASS-dev] Add a cost distance measure to GRASS GIS lib

2012-03-01 Thread Benjamin Ducke
Hi All, I have been pondering this for a while and would like to know if people on this list think the following would be a feasible/useful addition to GRASS (7): How about, in addition to the MASK raster, we'd also allow the user to specify a COST raster? This would allow all raster modules that