[Qgis-user] Displaying slope when digitizing a road
Markus Weidenbach
landconsult at freenet.de
Wed May 16 07:31:15 PDT 2012
Giovanni,
is it that easy? Please note that I want to see the slope value of the
vector and not the slope of the terrain.
Imagine a steep forest site with a 50% slope, so all cell values of the
slope grid have a value of 50%. If I am digitizing a road vector
parallel to the isolines in the middle of that steep side, the slope
value of that vector line is 0 and it changes when I am moving the
vector line towards the upper or lower isoline. When I am drawing the
vector line in a rectangular angle to the isoline, the slope value gets
close to 50%, what corresponds to the cell value of the terrain.
So, when using the isolines as a basis, the slope value of the vector
line is a function of its length and its angle to the closest isoline
.... well, but maybe you are right and using the profile plugin is a
possibility to describe and calculate the slope value of the vector line.
But would this be possible in real time, similar to the QGIS Measuring
Tool where you see the length of a line immidiatley when you move the
mouse over the screen?
Markus
--
Dr. Markus Weidenbach
*landConsult.de*
Geographical Information Management
and Environmental Planning
D-77815 Bühl
Germany
e.mail see: http://landConsult.de
Am 16.05.2012 15:16, schrieb G. Allegri:
> Do you mean something like a dialog showing the slope value while
> digitizing?
> If yes, it shouldn't be lot work. Grabbing some lines from the profile
> plugin would be the biggest part.
>
> giovanni
>
> 2012/5/16 Markus Weidenbach <landconsult at freenet.de
> <mailto:landconsult at freenet.de>>
>
> Thanks Maning but - yes, that´s not what I am looking for ... :-(
> Regards,
> Markus
>
> --
> Dr. Markus Weidenbach
> *landConsult.de*
> Geographical Information Management
> and Environmental Planning
> D-77815 Bühl
> Germany
> e.mail see: http://landConsult.de
>
> Am 16.05.2012 13:27, schrieb maning sambale:
>> Not exactly what you need, but perhaps an inspiration for a new plugin
>> is the terrain profile plugin:
>> http://spatialgalaxy.net/2012/01/06/qgis-plugin-of-the-week-profile/
>>
>> On Wed, May 16, 2012 at 6:57 PM, Markus Weidenbach
>> <landconsult at freenet.de> <mailto:landconsult at freenet.de> wrote:
>>> Dear List,
>>>
>>> does anybody know if there is a Plugin or Extension for QGIS that displays
>>> the actual slope of a vector when digitising a road on a DTM or slope map?
>>> The idea is to have a digitising tool to support forest road planning in
>>> QGIS by displaying the actual slope of a vector in real time when drawing
>>> the vector over a DTM or slope map.
>>> Has anybody the know-how to program such a tool?
>>> All comments are appreciated!
>>>
>>> Regards,
>>>
>>> Markus
>>>
>>> --
>>> Dr. Markus Weidenbach
>>> landConsult.de
>>> Geographical Information Management
>>> and Environmental Planning
>>> D-77815 Bühl
>>> Germany
>>> e.mail see:http://landConsult.de
>>>
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