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

[Shane Carey]

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 <careyshan at gmail.com> wrote:

> 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?
>
> <http://goog_326768947>
>
> https://docs.google.com/presentation/d/1x7IQ3BJlLLSb6R2atxIIiaeWzyCqCZQ3uWaGPZyo6ds/edit?usp=sharing
>
> Or if you think there is a better way of reaching my end goal (slide 2), I
> would be interested in hearing your thoughts.
> Thanks
>
> Thanks
>
> Le gach dea ghui,
> *Shane Carey*
> *GIS and Data Solutions Consultant*
>
>
> On Tue, Oct 16, 2018 at 6:38 AM Johannes Radinger <
> johannesradinger at gmail.com> wrote:
>
>> 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
>> transform to a vector map and use to intersect with your floodplain vector.
>>
>> best
>> Johannes
>>
>> On Tue, Oct 16, 2018 at 1:24 AM Shane Carey <careyshan at gmail.com> wrote:
>>
>>> 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 <careyshan at gmail.com> wrote:
>>>
>>>> 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 <neteler at osgeo.org>
>>>> wrote:
>>>>
>>>>> On Sun, Oct 14, 2018 at 11:28 PM Shane Carey <careyshan at gmail.com>
>>>>> 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 script?
>>>>> >
>>>>> > The link attached shows two slides. Stage one is the first slide and
>>>>> slide two is what I hope to end up with.
>>>>> >
>>>>> >
>>>>> https://docs.google.com/presentation/d/1x7IQ3BJlLLSb6R2atxIIiaeWzyCqCZQ3uWaGPZyo6ds/edit?usp=sharing
>>>>>
>>>>> This addon seems to do (similar) perpendicular line creation:
>>>>>   v.civil - Generates a alignment for designing roads, channels, and
>>>>> ports in civil engineering
>>>>>   https://grass.osgeo.org/grass7/manuals/addons/v.civil.html
>>>>>
>>>>> Best
>>>>> Markus
>>>>>
>>>>> --
>>>>> Markus Neteler, PhD
>>>>> http://www.mundialis.de - free data with free software
>>>>> http://grass.osgeo.org
>>>>> http://courses.neteler.org/blog
>>>>>
>>>> --
>>> Le gach dea ghui,
>>> *Shane Carey*
>>> *GIS and Data Solutions Consultant*
>>> _______________________________________________
>>> grass-user mailing list
>>> grass-user at lists.osgeo.org
>>> https://lists.osgeo.org/mailman/listinfo/grass-user
>>
>>
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