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GRASS and vector fields i.e. winds/ocean currents

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GRASS and vector fields i.e. winds/ocean currents Brendan 04-20-2007
Posted by Brendan on April 20, 2007, 10:39 am
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GRASS related question:

I work with vector fields such as wind and ocean currents as opposed
to scalar fields such as temperature, elevation etc. Vector fields can
often be represented as complex numbers as opposed to real numbers.

As far as I can tell GRASS has no capability to display, manipulate,
or output vector fields. Please tell me I am wrong and point me in the
right direction. I have browsed the GRASS docs and done various Google
searches with no results. The problem is compounded by the fact that I
mean vector fields, and not necessarily vector based data.

Thanks,


Posted by user923005 on April 20, 2007, 2:46 pm
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> GRASS related question:
>
> I work with vector fields such as wind and ocean currents as opposed
> to scalar fields such as temperature, elevation etc. Vector fields can
> often be represented as complex numbers as opposed to real numbers.
>
> As far as I can tell GRASS has no capability to display, manipulate,
> or output vector fields. Please tell me I am wrong and point me in the
> right direction. I have browsed the GRASS docs and done various Google
> searches with no results. The problem is compounded by the fact that I
> mean vector fields, and not necessarily vector based data.

I don't know about Grass and vector fields, so someone else will have
to answer that.
But I have used NCAR graphics, and vector fields are right in their
wheelhouse.
http://ngwww.ucar.edu/


Posted by GeoBDK on April 21, 2007, 4:12 am
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HI All

I am GRASS developer and also user.
GRASS having a lot of capabilities for vector. GRASS is purposly made
for Vector and latter Raster started.
But you have to import that file in gdal format.
I like to suggest the Brendan Please go to GRASS wiki and find some
GRASSaddOnes. or mail me your detail problem.

sincerely
Babu




>
> > GRASS related question:
>
> > I work with vector fields such as wind and ocean currents as opposed
> > to scalar fields such as temperature, elevation etc. Vector fields can
> > often be represented as complex numbers as opposed to real numbers.
>
> > As far as I can tell GRASS has no capability to display, manipulate,
> > or output vector fields. Please tell me I am wrong and point me in the
> > right direction. I have browsed the GRASS docs and done various Google
> > searches with no results. The problem is compounded by the fact that I
> > mean vector fields, and not necessarily vector based data.
>
> I don't know about Grass and vector fields, so someone else will have
> to answer that.
> But I have used NCAR graphics, and vector fields are right in their
> wheelhouse.http://ngwww.ucar.edu/



Posted by MN on April 22, 2007, 3:16 pm
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> GRASS related question:
>
> I work with vector fields such as wind and ocean currents as opposed
> to scalar fields such as temperature, elevation etc. Vector fields can
> often be represented as complex numbers as opposed to real numbers.
>
> As far as I can tell GRASS has no capability to display, manipulate,
> or output vector fields. Please tell me I am wrong and point me in the
> right direction. I have browsed the GRASS docs and done various Google
> searches with no results. The problem is compounded by the fact that I
> mean vector fields, and not necessarily vector based data.
>
> Thanks,

Brendan,

you may check d.rast.arrow
http://grass.itc.it/grass63/manuals/html63_user/d.rast.arrow.html

Example:
http://mpa.itc.it/markus/grass61/demos/drastarrow.png

There are a PNG driver and since GRASS 6.3 also a
Postscript driver to export the resulting map.

hope this helps,
Markus


Posted by Brendan on April 24, 2007, 7:37 am
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Thanks for your replies. I guess the buzzword I was looking for was
"aspect data". Sometimes the problem is simply finding the correlation
between different jargons. In GIS terminology does "aspect data" mean
all multivariate data, or just paired scalar/direction data?



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