[GRASS-user] New User

[Rich Shepard]

On Mon, 28 Feb 2011, Thomas D. Dean wrote:

> I know little or nothing about mapping.  I want to understand how the
> data files and grass connect together.  Some tutorial using known data
> followed by some information on various data formats and how to convert
> them into something GRASS can handle

Thomas,

   First, there is a tutorial of sorts using the Spearfish, ND data sets.
Second, GRASS is a tool for spatial analyses and modeling, and as such
requires users to know how to properly use the tool. I do not intend to
sound condescending, but I highly recommend you read a book or information
found on the Web about GIS, data formats, spatial analyses, and related
subjects.

>> In general it's not so bad, and you can do matlab/oct to and from grass
>> without much hassle.

   MatLab (and Octave) are totally different tools. I've used Octave to
calculate eigenvectors of symetrical matrices, but would not use it for any
spatial analyses.

> I have data consisting of bearings amd/or distances from known points, in
> octave.  I want to plot the bearing lines and the distance arcs on a wgs84
> ellipsoid with national boundaries (outlines).  The end result is to
> visually locate the intersections of the various lines with national
> outlines for easier identification of RF sources.

   This GRASS can do.

> The data from natural earth is 10m_admin_0_countries.dbf - spreadsheet
> database file 10m_admin_0_countries.prj - projection
> 10m_admin_0_countries.shp - shape file 10m_admin_0_countries.shx

   What you want is File -> Import vector data -> <top menu choice> for ESRI
.shp files. Select the .shp as the file to open. Or, use v.in.ogr from the
command line.

> I have not discovered how to bring the map data into grass.  How do I
> arrange the data files so GRASS can find/inport them?  I have a
> $home/grassdata directory structure with worldlocation.tar.gz expanded
> into it as $home/grassdata/worldlocation.  How do I access/plot this
> data in GRASS?

   Put your shape files in there, too. Read the quick introduction to GRASS
on the Web site as it explains the relationships among the root database,
locations, and mapsets. It's all there and very well written.

Rich