I was wondering if v.to.db could have a "azimuth" option, to calculate
the azimuth of line segments, based on the end vertices coordinates.
Carlos
--
+-----------------------------------------------------------+
Carlos Henrique Grohmann - Guano
Geologist M.Sc - Doctorate Student at IGc-USP - Brazil
Linux User #89721 - carlos dot grohmann at gmail dot com
+-----------------------------------------------------------+
I'm not sure exactly what you need. But this might help.
1) Convert the nodes of your coverage to points using v.to.points
(format=point option)
2) Dump the points as an ascii text stream using v.to.ascii and pipe
the results into a
script that calculates the azimuth.
I have written a small python utility that calculates the distance and
azimuth along a list of points:
http://students.washington.edu/dfinlays/scripts/cogop.py
Here is an example of how it can be used. I have a polygon called
trimpoly. I convert it to a list of points using v.to.points:
GRASS 6.1.cvs (UTM10_NAD83): > v.to.points -v input=trimpoly output=trimpolypts
Building topology ...
20 primitives registered
Building areas: 100%
0 areas built
0 isles built
Attaching islands:
Attaching centroids: 100%
Topology was built.
Number of nodes : 19
Number of primitives: 20
Number of points : 20
Number of lines : 0
Number of boundaries: 0
Number of centroids : 0
Number of areas : 0
Number of isles : 0
20 points written to output map
Now I can dump this point file as ascii text:
v.out.ascii input=trimpolypts
536022.25|5332267.25|-1
536029.98|5332292.26|-1
536041|5332314.36|-1
536066.78|5332355.57|-1
536081.01|5332349.24|-1
536098.13|5332341.62|-1
...
We can get rid of the pipe characters and replace them with tabs with
sed and then
pipe the result to my cogop.py script like this:
v.out.ascii input=trimpolypts | sed 's/|/\t/g' | cogop -a
0.0 536022.25 5332267.25 -1
26.18 17.18 536029.98 5332292.26 -1
24.7 26.5 536041 5332314.36 -1
48.61 32.03 536066.78 5332355.57 -1
15.57 113.98 536081.01 5332349.24 -1
18.74 113.99 536098.13 5332341.62 -1
The first column is the distance between points, the second column is
the azimuth from point 1 to point 2, finally, the script appends the
input fields. cogop has a few other options like setting a benchmark
and calculating cumulative distance, etc. Of course the order of the
points is important.
Hope that gives you some ideas,
David
On 8/8/05, Carlos Guâno Grohmann <carlos.grohmann@gmail.com> wrote:
I was wondering if v.to.db could have a "azimuth" option, to calculate
the azimuth of line segments, based on the end vertices coordinates.Carlos
--
+-----------------------------------------------------------+
Carlos Henrique Grohmann - Guano
Geologist M.Sc - Doctorate Student at IGc-USP - Brazil
Linux User #89721 - carlos dot grohmann at gmail dot com
+-----------------------------------------------------------+
--
David Finlayson
Marine Geology & Geophysics
School of Oceanography
Box 357940
University of Washington
Seattle, WA 98195-7940
USA
Office: Marine Sciences Building, Room 112
Phone: (206) 616-9407
Web: http://students.washington.edu/dfinlays
The script url was wrong, here is the correct url:
http://students.washington.edu/dfinlays/scripts/2005/cogop.py
David
On 8/8/05, David Finlayson <david.p.finlayson@gmail.com> wrote:
I'm not sure exactly what you need. But this might help.
1) Convert the nodes of your coverage to points using v.to.points
(format=point option)2) Dump the points as an ascii text stream using v.to.ascii and pipe
the results into a
script that calculates the azimuth.I have written a small python utility that calculates the distance and
azimuth along a list of points:http://students.washington.edu/dfinlays/scripts/cogop.py
Here is an example of how it can be used. I have a polygon called
trimpoly. I convert it to a list of points using v.to.points:GRASS 6.1.cvs (UTM10_NAD83): > v.to.points -v input=trimpoly output=trimpolypts
Building topology ...
20 primitives registered
Building areas: 100%
0 areas built
0 isles built
Attaching islands:
Attaching centroids: 100%
Topology was built.
Number of nodes : 19
Number of primitives: 20
Number of points : 20
Number of lines : 0
Number of boundaries: 0
Number of centroids : 0
Number of areas : 0
Number of isles : 0
20 points written to output mapNow I can dump this point file as ascii text:
> v.out.ascii input=trimpolypts
536022.25|5332267.25|-1
536029.98|5332292.26|-1
536041|5332314.36|-1
536066.78|5332355.57|-1
536081.01|5332349.24|-1
536098.13|5332341.62|-1
...We can get rid of the pipe characters and replace them with tabs with
sed and then
pipe the result to my cogop.py script like this:> v.out.ascii input=trimpolypts | sed 's/|/\t/g' | cogop -a
0.0 536022.25 5332267.25 -1
26.18 17.18 536029.98 5332292.26 -1
24.7 26.5 536041 5332314.36 -1
48.61 32.03 536066.78 5332355.57 -1
15.57 113.98 536081.01 5332349.24 -1
18.74 113.99 536098.13 5332341.62 -1The first column is the distance between points, the second column is
the azimuth from point 1 to point 2, finally, the script appends the
input fields. cogop has a few other options like setting a benchmark
and calculating cumulative distance, etc. Of course the order of the
points is important.Hope that gives you some ideas,
David
On 8/8/05, Carlos Guâno Grohmann <carlos.grohmann@gmail.com> wrote:
> I was wondering if v.to.db could have a "azimuth" option, to calculate
> the azimuth of line segments, based on the end vertices coordinates.
>
> Carlos
> --
> +-----------------------------------------------------------+
> Carlos Henrique Grohmann - Guano
> Geologist M.Sc - Doctorate Student at IGc-USP - Brazil
> Linux User #89721 - carlos dot grohmann at gmail dot com
> +-----------------------------------------------------------+
>
>--
David Finlayson
Marine Geology & Geophysics
School of Oceanography
Box 357940
University of Washington
Seattle, WA 98195-7940
USAOffice: Marine Sciences Building, Room 112
Phone: (206) 616-9407
Web: http://students.washington.edu/dfinlays
--
David Finlayson
Marine Geology & Geophysics
School of Oceanography
Box 357940
University of Washington
Seattle, WA 98195-7940
USA
Office: Marine Sciences Building, Room 112
Phone: (206) 616-9407
Web: http://students.washington.edu/dfinlays
I have a C program that read a ASCII vector from GRASS_5 and
calculates the length and azimuth of the lines. I will have to use it,
then. It's just that I think I saw somewhere that v.to.db could do it
(it does for length..).
Carlos
On 8/8/05, David Finlayson <david.p.finlayson@gmail.com> wrote:
The script url was wrong, here is the correct url:
http://students.washington.edu/dfinlays/scripts/2005/cogop.py
David
On 8/8/05, David Finlayson <david.p.finlayson@gmail.com> wrote:
> I'm not sure exactly what you need. But this might help.
>
> 1) Convert the nodes of your coverage to points using v.to.points
> (format=point option)
>
> 2) Dump the points as an ascii text stream using v.to.ascii and pipe
> the results into a
> script that calculates the azimuth.
>
> I have written a small python utility that calculates the distance and
> azimuth along a list of points:
>
> http://students.washington.edu/dfinlays/scripts/cogop.py
>
> Here is an example of how it can be used. I have a polygon called
> trimpoly. I convert it to a list of points using v.to.points:
>
> GRASS 6.1.cvs (UTM10_NAD83): > v.to.points -v input=trimpoly output=trimpolypts
> Building topology ...
> 20 primitives registered
> Building areas: 100%
> 0 areas built
> 0 isles built
> Attaching islands:
> Attaching centroids: 100%
> Topology was built.
> Number of nodes : 19
> Number of primitives: 20
> Number of points : 20
> Number of lines : 0
> Number of boundaries: 0
> Number of centroids : 0
> Number of areas : 0
> Number of isles : 0
> 20 points written to output map
>
> Now I can dump this point file as ascii text:
>
> > v.out.ascii input=trimpolypts
> 536022.25|5332267.25|-1
> 536029.98|5332292.26|-1
> 536041|5332314.36|-1
> 536066.78|5332355.57|-1
> 536081.01|5332349.24|-1
> 536098.13|5332341.62|-1
> ...
>
> We can get rid of the pipe characters and replace them with tabs with
> sed and then
> pipe the result to my cogop.py script like this:
>
> > v.out.ascii input=trimpolypts | sed 's/|/\t/g' | cogop -a
> 0.0 536022.25 5332267.25 -1
> 26.18 17.18 536029.98 5332292.26 -1
> 24.7 26.5 536041 5332314.36 -1
> 48.61 32.03 536066.78 5332355.57 -1
> 15.57 113.98 536081.01 5332349.24 -1
> 18.74 113.99 536098.13 5332341.62 -1
>
> The first column is the distance between points, the second column is
> the azimuth from point 1 to point 2, finally, the script appends the
> input fields. cogop has a few other options like setting a benchmark
> and calculating cumulative distance, etc. Of course the order of the
> points is important.
>
> Hope that gives you some ideas,
>
> David
>
>
> On 8/8/05, Carlos Guâno Grohmann <carlos.grohmann@gmail.com> wrote:
> > I was wondering if v.to.db could have a "azimuth" option, to calculate
> > the azimuth of line segments, based on the end vertices coordinates.
> >
> > Carlos
> > --
> > +-----------------------------------------------------------+
> > Carlos Henrique Grohmann - Guano
> > Geologist M.Sc - Doctorate Student at IGc-USP - Brazil
> > Linux User #89721 - carlos dot grohmann at gmail dot com
> > +-----------------------------------------------------------+
> >
> >
>
>
> --
> David Finlayson
> Marine Geology & Geophysics
> School of Oceanography
> Box 357940
> University of Washington
> Seattle, WA 98195-7940
> USA
>
> Office: Marine Sciences Building, Room 112
> Phone: (206) 616-9407
> Web: http://students.washington.edu/dfinlays
>--
David Finlayson
Marine Geology & Geophysics
School of Oceanography
Box 357940
University of Washington
Seattle, WA 98195-7940
USAOffice: Marine Sciences Building, Room 112
Phone: (206) 616-9407
Web: http://students.washington.edu/dfinlays
--
+-----------------------------------------------------------+
Carlos Henrique Grohmann - Guano
Geologist M.Sc - Doctorate Student at IGc-USP - Brazil
Linux User #89721 - carlos dot grohmann at gmail dot com
+-----------------------------------------------------------+