[GRASS-user] New User

Hamish hamish_b at yahoo.com
Mon Feb 28 02:25:52 EST 2011

Thomas wrote:
> I am a new user, just discovered grass and OSGeo. My current
> interest is accessing the files from NaturalEarthData,
> converting them into matlab format, and, using octave to
> manipulate and/or plot.
> I use Linux and Unix. Octave 3.4.0, Gnuplot, Grass
> 6.4.0.  This workstation has Ubuntu 10.04.
> I downloaded the
> 10m-admin-0-countries.zip   and
> 10m-admin-0-boundary-lines-land.zip files from
> NaturalEarthData.
> I want to use grass to display some portion of the data.
> Then, use r.out.mat to generate a octave compatible binary
> file.
> I started looking at the manual, but, quickly became
> confused.

that would be my fault.

> Is there a simple how to for what I want to do?

Could you explain your workflow a bit more? there are many
choices.   In general it's not so bad, and you can do matlab/oct
to and from grass without much hassle.

natural earth is polyline data, so vector & thus v.* modules.
2D array is raster data, so r.* modules.
see v.to.rast and r.to.vect modules.

do you have 2D arrays in matlab/octave from contourf() or similar
and you want to fill(), area(), or patch() a polygon coastline
over the top?
see  http://grass.osgeo.org/wiki/Addons#v.out.ascii.mat

are you using the (free/gratis) m_map toolbox?
or matlab's mapping toolbox? (which is using proj4, same as us)

do you wish to rasterize the natural earth polygons into a 2D
see v.to.rast + r.out.mat

do you want to bring your matlab data into grass and plot it
see r.in.mat, or v.in.lines, v.in.mapgen.

the first step is to bring the data into grass with v.in.ogr.



More information about the grass-user mailing list