Re: [GRASS-user] Cut a floodplain polygon with 1meter wide polygons perpendicular to its river channel

Had another brainwave. Is it possible to create a perpendicular line at every vertex that makes up the river line segment? Thanks Le gach dea ghui, *Shane Carey* *GIS and Data Solutions Consultant* On Tue, Oct 16, 2018 at 6:15 PM Shane Carey wrote: > Hi All, > > I am getting closer to what I

Re: [GRASS-user] Cut a floodplain polygon with 1meter wide polygons perpendicular to its river channel

Hi All, I am getting closer to what I want. Is there a way to cut the floodplain polygon where it "narrows" in, i.e. at the green lines on slide 6. I need some way of automating this. https://docs.google.com/presentation/d/1x7IQ3BJlLLSb6R2atxIIiaeWzyCqCZQ3uWaGPZyo6ds/edit#slide=id.g45038c0552_0_0

Re: [GRASS-user] Cut a floodplain polygon with 1meter wide polygons perpendicular to its river channel

>What about obtaining the main direction of the river (North - South/ East- West) and creating the >rows/columns based on that? isn't it that was v.transect does? - best regards Helmut -- Sent from: http://osgeo-org.1560.x6.nabble.com/Grass-Users-f3884509.html

Re: [GRASS-user] Cut a floodplain polygon with 1meter wide polygons perpendicular to its river channel

What about obtaining the main direction of the river (North - South/ East- West) and creating the rows/columns based on that? Any advice/ help would be appreciated! Thanks all Le gach dea ghui, *Shane Carey* *GIS and Data Solutions Consultant* On Tue, Oct 16, 2018 at 7:49 AM Shane Carey wrote:

Re: [GRASS-user] Cut a floodplain polygon with 1meter wide polygons perpendicular to its river channel

Ok, I seem to be getting closer to what I need. It works well where the river is perpendicular to the column (see slide 3) but where it is parrallel (see slide 4), I would need to obtain a rows map. Is there any way of being able to tell it to create rows or columns based on the river direction?

Re: [GRASS-user] Cut a floodplain polygon with 1meter wide polygons perpendicular to its river channel

>I don't think v.transects is going to work for me as lines appear to be cutting across each other. Is there >another tool in Grass that can cut the floodplain polygon into 5m lengths (as green lines in image attached) what about v.mkgrid and overlay the resulting grid with the floodplain?

Re: [GRASS-user] Cut a floodplain polygon with 1meter wide polygons perpendicular to its river channel

It seems that would would like to have your floodplain cut based on the columns of the underlying raster-resolution (and not perpendicular to the river line as initially stated). You could use mapcalc to generate a column raster map (r.mapcalc expression="colmap = col()") which you could then

Re: [GRASS-user] Cut a floodplain polygon with 1meter wide polygons perpendicular to its river channel

Hi All, I don't think v.transects is going to work for me as lines appear to be cutting across each other. Is there another tool in Grass that can cut the floodplain polygon into 5m lengths (as green lines in image attached) Thanks On Luan 15 DFómh 2018 at 15:38, Shane Carey wrote: > Great

Re: [GRASS-user] Cut a floodplain polygon with 1meter wide polygons perpendicular to its river channel

Great thanks, is there anything available that will snap these lines to the polygon edges? Thanks Le gach dea ghui, *Shane Carey* *GIS and Data Solutions Consultant* On Mon, Oct 15, 2018 at 3:30 PM Markus Neteler wrote: > On Sun, Oct 14, 2018 at 11:28 PM Shane Carey wrote: > > > > Hi, > > >

Re: [GRASS-user] Cut a floodplain polygon with 1meter wide polygons perpendicular to its river channel

On Sun, Oct 14, 2018 at 11:28 PM Shane Carey wrote: > > Hi, > > I need to cut a floodplain polygon into one meter strips which are > perpendicular to the river. This needs to be an automated process. Just > wondering has anyone ever done this or similar in Grass GIS through python or > a bash

Re: [GRASS-user] Cut a floodplain polygon with 1meter wide polygons perpendicular to its river channel

Just one quick thing, do you know if dleft and dright can snap to the polygon edge? Thanks On Domh 14 DFómh 2018 at 23:30, Shane Carey wrote: > Super, thanks Johannes. I'll check it out and see how it works. > Super - thanks > > On Domh 14 DFómh 2018 at 23:15, Johannes Radinger < >

Re: [GRASS-user] Cut a floodplain polygon with 1meter wide polygons perpendicular to its river channel

Super, thanks Johannes. I'll check it out and see how it works. Super - thanks On Domh 14 DFómh 2018 at 23:15, Johannes Radinger < johannesradin...@gmail.com> wrote: > Shane, > > have a look at the GRASS v.transect add-on: > https://grass.osgeo.org/grass74/manuals/addons/v.transects.html > The

Re: [GRASS-user] Cut a floodplain polygon with 1meter wide polygons perpendicular to its river channel

Shane, have a look at the GRASS v.transect add-on: https://grass.osgeo.org/grass74/manuals/addons/v.transects.html The manual says: "Creates transect lines or quadrilateral areas at regular intervals perpendicular to a polyline." HTH Johannes On Sun, Oct 14, 2018 at 11:28 PM Shane Carey wrote:

[GRASS-user] Cut a floodplain polygon with 1meter wide polygons perpendicular to its river channel

Hi, I need to cut a floodplain polygon into one meter strips which are perpendicular to the river. This needs to be an automated process. Just wondering has anyone ever done this or similar in Grass GIS through python or a bash script? The link attached shows two slides. Stage one is the first