RE: [GRASS-dev] Re: [GRASS-user] how to import NetCDF data??

GRASS GIS GRASS GIS developer
,
1

By the way, I've been wanting to import some tsunami models into GRASS, but it is a pain to extract 100's of time slices with gdal_translate and then import them into GRASS. So, an easy way to import NetCDF files into GRASS would make my job easier. Looking forward to giving Soren's new temporal GIS framework a try!

Bob Moskovitz
Seismic Hazards Mapping Program
California Geological Survey

-----Original Message-----
From: grass-dev-bounces@lists.osgeo.org on behalf of Michael Barton
Sent: Wed 2/8/2012 9:57 AM
To: Jennifer Boehnert
Cc: Helena Mitasova; Kirk Wythers; developers grass-developers; Kyngesburye William; GRASS@lists.osgeo.org
Subject: [GRASS-dev] Re: [GRASS-user] how to import NetCDF data??

This will be even more important with Soren's new temporal GIS framework. Many netcdf climate files are the equivalent of 'time-cubes'. Being able to read/write these easily would provide a very rich source of data to use in temporal GIS analyses.

Michael
____________________
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University

voice: 480-965-6262 (SHESC), 480-727-9746 (CSDC)
fax: 480-965-7671 (SHESC), 480-727-0709 (CSDC)
www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu

On Feb 8, 2012, at 10:14 AM, Jennifer Boehnert wrote:

Thank you everyone for all the support, suggestions and feedback. I am
trying to create a course using GRASS which I would teach in Latin
America and eventually hopefully in Africa working on vulnerability
assessements using climate change model output from NCAR. My netCDF
data is from the CCSM which was in by the IPCC AR4, it is netCDF3 and
using the CF-convention. It is a pretty typical netCDF file and it
would be great if we could read it into GRASS directly without having to
convert it to a geotiff or any other format, if possible.
Thanks Jennifer

On 2/8/2012 10:05 AM, Michael Barton wrote:

Lack of NetCDF support would be a problem for sure. We wondered about
that. Jennifer is trying on Windows and I'm on a Mac.

Michael
____________________
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University

voice: 480-965-6262 (SHESC), 480-727-9746 (CSDC)
fax: 480-965-7671 (SHESC), 480-727-0709 (CSDC)
www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu

On Feb 8, 2012, at 9:16 AM, Kirk Wythers wrote:

Michael,

I could not open the file in GRASS either. I have attached the errors
I got. They look like the same that you were describing (I tried both
with and without the -o flag). I did however remember the work around
I used, which was to:

1. import the .nc files into MATLAB
2. Export as GeoTIffs
3. Read the GeoTiffs into GRASS

This made sense for me partly because I needed to aggregate daily
values to monthly means which I did in step 1, but then never thought
much more about why I couldn't import directly into GRASS . Your
problem motivated me to look into why I needed this workaround in the
first place (which is not much of a workaround unless you have access
to MATLAB). which appears to be that my gdal does not have GMT/netcdf
support either (as Markus pointed out yesterday). I am also using
WIlliams binaries and frameworks.

I agree that more detail in the wiki would be helpful, but I think the
first step is to compile to update gdal with GMT/NetCDF support.
Perhaps William would be interested?

===================================================================================================================================
GRASS ERRORS:

GRASS 6.4.1 (latlon):~ > r.in.gdal
input=~/Desktop/ppt_SRESA2_mid_annual_down_anomaly.nc
output=ppt_SRESA2_mid_annual_down_anomaly
ERROR: Projection of dataset does not appear to match current location.

Location PROJ_INFO is:
name: Lat/Lon
proj: ll
datum: nad83
ellps: grs80
towgs84: 0,0,0,0,0,0,0
no_defs: defined

Import dataset PROJ_INFO is:
cellhd.proj = 0 (unreferenced/unknown)

You can use the -o flag to r.in.gdal to override this check and use
the location definition for the dataset.
Consider generating a new location from the input dataset using the
'location' parameter.

GRASS 6.4.1 (latlon):~ > r.in.gdal -o
input=~/Desktop/ppt_SRESA2_mid_annual_down_anomaly.nc
output=ppt_SRESA2_mid_annual_down_anomaly
WARNING: Over-riding projection check
WARNING: G_set_window(): Illegal latitude for North
GRASS 6.4.1 (latlon):~ >

On Feb 7, 2012, at 9:10 PM, Michael Barton wrote:

Thanks Kirk,

Here is a copy of the smallest file we tried. The big ones gave
identical errors.

Michael

<ppt_SRESA2_mid_annual_down_anomaly.nc>

____________________
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University

voice: 480-965-6262 (SHESC), 480-727-9746 (CSDC)
fax: 480-965-7671 (SHESC), 480-727-0709 (CSDC)
www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu
<http://csdc.asu.edu/&gt;

On Feb 7, 2012, at 11:49 AM, Kirk Wythers wrote:

I had to import a bunch of SSURGO NetCDF data not too long ago
Michael (I was going back and forth with GRASS and MATLAB). I don't
seem to remember having any trouble with gdal (which means that it
must have worked!) Are you sure that the NetCDF is Lat Long?

What was your error exactly? Is the file too big to share? If not
send it to me and I'll take a look.

Best,

Kirk

Kirk R. Wythers
Department of Forest Resources
University of Minnesota
St. Paul, MN 55108
tel: 612.625.2261
email: kwythers@umn.edu <mailto:kwythers@umn.edu>

On Feb 7, 2012, at 12:33 PM, Michael Barton wrote:

I'm trying to help someone at NCAR import NetCDF data and we keep
getting an illegal north latitude error. Looking at the GDAL info,
I think we need to specify some additional metadata, but the GDAL
page stops short of giving an example of how to do this. Has anyone
imported climate data this way?

Thanks
Michael
____________________
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University

voice: 480-965-6262 (SHESC), 480-727-9746 (CSDC)
fax: 480-965-7671 (SHESC), 480-727-0709 (CSDC)
www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu
<http://csdc.asu.edu/&gt;

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Jennifer Boehnert
GIS Coordinator
National Center of Atmospheric Research
PO Box 3000
Boulder, CO, 80307

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