[GRASS-user] how to import e00 data

[Nikos Alexandris]

Simone Gabbriellini wrote:

> Hello List,

Hello Simone,

 
> this is my first attempt with Grass,

Have a nice ride with GRASS GIS :-). Invest some time, it'll "payback" 
multiple times. As a starter, it is advised to warm-up with some stuff over 
at:
<http://grasswiki.osgeo.org/wiki/GRASS_Help#First_Day_Documentation>.

First thing you need to do in any case, is to set-up a location based on the 
spatial reference system of the data you plan to work with.

Check some stuff here: <http://grass.osgeo.org/grass64/manuals/helptext.html> 
and here: <http://grasswiki.osgeo.org/wiki/Importing_data>.



> I am trying to visualize administrative boundaries of India... I am trying
> to load e00 files that I downloaded from
> http://data.geocomm.com/catalog/IN/group109.html

So, GRASS GIS has its own vector (and raster) formats. You need to import the 
data first in GRASS' data base. 

> Now, I really cannot understand how to import these data.

For "e00" files, there is a module called "v.in.e00". The help/manual pages 
is: http://grass.osgeo.org/grass64/manuals/v.in.e00.html

You need to use this module in order to get the data of interest inside GRASS' 
data base.


> I don't understand the coordinates type of these data, thus I do not know
> what to specify when Grass starts.

I had a quick look. The data are "nailed" in geographic coordinates. The 
"ESPG" code for the "WGS84" reference system is "4326". You need to define a 
new grass location based on the "EPSG:4326". There are also other ways to do 
that, not only the epsg-code.


> The error message I have is:
> 
> WARNING: Datum <Not_specified_based_on_Clarke_1866_ellipsoid> not
> recognised by GRASS and no parameters found
> ERROR: Projection of dataset does not appear to match current location.
> 
> I know this is not much information, but really I have no clue of what
> I have to do in order to display these data, so any hint/advice on
> best practice about how to proceed will be more than welcome.

After importing, set the active region to match the extent of the data (you 
imported/you want to display, edit, et.c.):

"g.region vect=ImportedData" in the command line.


> Best regards,
> Simone

Give it a try, report back if things don't roll.

Best, Nikos