[GRASS-user] how to import e00 data

GRASS GRASS user
1

Hello List,

this is my first attempt with Grass, 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

Now, I really cannot understand how to import these data. I don't
understand the coordinates type of these data, thus I do not know what
to specify when Grass starts. 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.

Best regards,
Simone

--
-----------------------------------------------------------------

Simone Gabbriellini, PhD

Post-doctoral Researcher
ANR founded research project "DIFFCERAM"
GEMASS, CNRS & Paris-Sorbonne.

mobile: +39 340 39 75 626
email: simone.gabbriellini@gmail.com

2

On Wed, 20 Nov 2013, Simone Gabbriellini wrote:

Now, I really cannot understand how to import these data. I don't
understand the coordinates type of these data, thus I do not know what to
specify when Grass starts. 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.

Simone,

   Take one step at a time.

   The .e00 file is plain ASCII text. Look at the file in a pager (less,
more, cat) and search for the string PRJ. That's the section of the file
that describes the projection for the coordinate data. Here's an example
from the file for Nevada geology:

PRJ 3
Projection ALBERS
Datum NAD83
Zunits NO
Units METERS
Spheroid GRS1980
Xshift 0.0000000000
Yshift 0.0000000000
Parameters
  29 30 0.000 /* 1st standard parallel
  45 30 0.000 /* 2nd standard parallel
-96 0 0.000 /* central meridian
  23 0 0.000 /* latitude of projection's origin
0.00000 /* false easting (meters)
0.00000 /* false northing (meters)
EOP

   Now you have all the information you need to create a location for that
data. Look at the getting started Web page to see how to create a location.

   Now you can start GRASS using that location. In the GIS Layer Manager
window select File -> Import vector data -> ESRI e00 import (v.in.e00). You
can do this directly from the command line with v.in.e00, but you most
likely want to work with the GUI until you get more familiar with the
application.

Rich

--
Richard B. Shepard, Ph.D. | Have knowledge, will travel.
Applied Ecosystem Services, Inc. |
<http://www.appl-ecosys.com> Voice: 503-667-4517 Fax: 503-667-8863

3

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&gt;\.

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&gt;
and here: <http://grasswiki.osgeo.org/wiki/Importing_data&gt;\.

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

4

Rich,

thanks for your time.

  The .e00 file is plain ASCII text. Look at the file in a pager (less,
more, cat) and search for the string PRJ. That's the section of the file
that describes the projection for the coordinate data. Here's an example
from the file for Nevada geology:

Did it, this is what I have:

PRJ 2
Projection GEOGRAPHIC
~
Zunits NO
~
Units DD
~
Spheroid CLARKE1866
~
Xshift 0.0000000000
~
Yshift 0.0000000000
~

Looks like the ESPG code is 4302, then I proceed to import all the
files, then add vector maps to layer manager... but I cannot see
anything there... just a white map display...

it never fails, but didn't show anything.

thanks,
Simone

5

On Wed, 20 Nov 2013, Simone Gabbriellini wrote:

Did it, this is what I have:

PRJ 2
Projection GEOGRAPHIC
Zunits NO
Units DD
Spheroid CLARKE1866

Simone,

   It's unprojected, lat/long, in decimal degrees.

Looks like the ESPG code is 4302, then I proceed to import all the files,
then add vector maps to layer manager... but I cannot see anything
there... just a white map display...

   From within the layer manager window select that map by right-clicking on
it. One of the menu options is to set the view to that map. Try this.

   I work infrequently with the ESPG codes; usually specify the location by
details. In your case I'd set a location called India-LL (for lat/long);
perhaps that's what the ESPG code represents.

Rich

--
Richard B. Shepard, Ph.D. | Have knowledge, will travel.
Applied Ecosystem Services, Inc. |
<http://www.appl-ecosys.com> Voice: 503-667-4517 Fax: 503-667-8863

6

mmm, I really give up... it's impossibly complicated to have a result.

Maybe I should try to find another GIS software, less powerful but simpler.

Thanks anyway for your help.

2013/11/20 Rich Shepard <rshepard@appl-ecosys.com>:

On Wed, 20 Nov 2013, Simone Gabbriellini wrote:

Did it, this is what I have:

PRJ 2
Projection GEOGRAPHIC
Zunits NO
Units DD
Spheroid CLARKE1866

Simone,

  It's unprojected, lat/long, in decimal degrees.

Looks like the ESPG code is 4302, then I proceed to import all the files,
then add vector maps to layer manager... but I cannot see anything
there... just a white map display...

  From within the layer manager window select that map by right-clicking on
it. One of the menu options is to set the view to that map. Try this.

  I work infrequently with the ESPG codes; usually specify the location by
details. In your case I'd set a location called India-LL (for lat/long);
perhaps that's what the ESPG code represents.

Rich

--
Richard B. Shepard, Ph.D. | Have knowledge, will travel.
Applied Ecosystem Services, Inc. |
<http://www.appl-ecosys.com> Voice: 503-667-4517 Fax: 503-667-8863

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--
-----------------------------------------------------------------

Simone Gabbriellini, PhD

Post-doctoral Researcher
ANR founded research project "DIFFCERAM"
GEMASS, CNRS & Paris-Sorbonne.

mobile: +39 340 39 75 626
email: simone.gabbriellini@gmail.com

7

Hi.

···

this is what I have:

PRJ 2
Projection GEOGRAPHIC
~
Zunits NO
~
Units DD
~
Spheroid CLARKE1866
~
Xshift 0.0000000000
~
Yshift 0.0000000000
~

Looks like the ESPG code is 4302

try a location with EPSG: 4008

Unknown datum based upon the Clarke 1866 ellipsoid

<4008> +proj=longlat +ellps=clrk66 +no_defs <>

4302 is Trinidad?

Trinidad 1903

<4302>

Mark

8

On Wed, Nov 20, 2013 at 5:19 PM, Simone Gabbriellini
<simone.gabbriellini@gmail.com> wrote:

mmm, I really give up... it's impossibly complicated to have a result.

Maybe I should try to find another GIS software, less powerful but simpler.

Or another dataset?
You are trying to import the "Digital Chart of the World" which is fairly old.

If that's the scope, we may assist. If you really wanted a modern
dataset, perhaps use a different one?
http://grasswiki.osgeo.org/wiki/Geodata#Global_Administrative_Areas

Best
Markus

9

Hi Simone,

If you are an ArcGIS user you may find setting up a GRASS location via QGIS and the GRASS plugin simpler to start with as it steps you through the process.

There are details of how to do this in LITA Practical 3 here: http://www.pushingthesensors.com/teaching-materials/

You can load the raster you have into QGIS, import it into your new GRASS location and fit the location to your imported raster for all subsequent processing. You can then continue to use via the GRASS plugin or in standalone GRASS.

Best,
Rebecca

On Thursday, 21 November 2013, 8:05, Markus Neteler neteler@osgeo.org wrote:

On Wed, Nov 20, 2013 at 5:19 PM, Simone Gabbriellini
<simone.gabbriellini@gmail.com> wrote:

mmm, I really give up… it’s impossibly complicated to have a result.

Maybe I should try to find another GIS software, less powerful but simpler.

Or another dataset?
You are trying to import the “Digital Chart of the World” which is fairly old.

If that’s the scope, we may assist. If you really wanted a modern
dataset, perhaps use a different one?
http://grasswiki.osgeo.org/wiki/Geodata#Global_Administrative_Areas

Best
Markus

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