Re: [GRASS-user] v.to.points: extract start/end nodes
Hi, so 16. 3. 2019 v 13:28 odesílatel Micha Silver napsal: > So, for me, an option in v.to.points to get the start and end points would > help to simplify this workflow. done in r74283 (trunk), will be included in 7.8 release. I also find strange that `dmax` option has defined default value (100 of map units), could be changed in G8 see [1]. Ma -- Martin Landa http://geo.fsv.cvut.cz/gwiki/Landa http://gismentors.cz/mentors/landa ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] v.to.points: extract start/end nodes
On 15/03/2019 22:45, Martin Landa wrote: Hi, pá 15. 3. 2019 v 15:01 odesílatel Moritz Lennert napsal: v.to.db with options start/end provides the coordinates of these points. thanks, I overlooked `v.to.db`. Anyway I would still need to hack around since `v.to.db` does not create a new output vector map. So it's still make sense to me to implement this functionality in `v.to.points`. Ma Whenever we get new Lidar data, I run a script to extract the streamlines network, then obtain the upstream flow accumulation area for both ends of each stream reach. The script uses a combination of v.db.update to get the x,y coordinates of both ends of each stream reach. Then these coordinates are extracted and piped into v.in.ascii, creating a new points vector. Next I get the upstream contributing area from the flow accumulation raster (v.what.rast). Finally an sql _expression_ is constructed for db.execute to update the streams vector with upstream area for each reach from the end points vector. So, for me, an option in v.to.points to get the start and end points would help to simplify this workflow. Cheers, Micha -- Micha Silver Ben Gurion Univ. Sde Boker, Remote Sensing Lab cell: +972-523-665918 ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] v.to.points: extract start/end nodes
Hi, pá 15. 3. 2019 v 15:01 odesílatel Moritz Lennert napsal: > v.to.db with options start/end provides the coordinates of these points. thanks, I overlooked `v.to.db`. Anyway I would still need to hack around since `v.to.db` does not create a new output vector map. So it's still make sense to me to implement this functionality in `v.to.points`. Ma -- Martin Landa http://geo.fsv.cvut.cz/gwiki/Landa http://gismentors.cz/mentors/landa ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] v.to.points: extract start/end nodes
On 15/03/19 14:03, Martin Landa wrote: Hi, I need to extract start or end nodes of lines into two separated output maps. Unfortunately `v.to.points` doesn't seems to support it (only `nodes` or `vertices` can be chosen). I am thinking to add such functionality to `v.to.points`. But before that, it can be that I am overlooking another tool which I am looking for? v.to.db with options start/end provides the coordinates of these points. Moritz ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] v.to.points: extract start/end nodes
Hi, I need to extract start or end nodes of lines into two separated output maps. Unfortunately `v.to.points` doesn't seems to support it (only `nodes` or `vertices` can be chosen). I am thinking to add such functionality to `v.to.points`. But before that, it can be that I am overlooking another tool which I am looking for? Thanks for pointers in advance, Ma -- Martin Landa http://geo.fsv.cvut.cz/gwiki/Landa http://gismentors.cz/mentors/landa ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
