[gradsusr] Geotiffs in Grads

[Yaqiang Wang]

Hi Nick,

I have checked your data. "20100424_160000.asc" is ESRI ASCII Grid
format data which could be supported in many GIS software. The problem
is I don't know the projection information of the data which is not
longitude/latitude coordinate, and the ESRI ASCII Grid format has no
information of the projection. The projection information should has
been included in the geotiff file.

On Wed, Dec 22, 2010 at 3:54 AM, Nick Heath <nkh09 at fsu.edu> wrote:
> Hi,
>
> Thank you both for the help!  I have found a way to convert the geotiffs into gridded data.  I have attached 2 of the output files after the conversion (I tried two different formats).  Now, I am a bit lost on how to make a control file with this data as I am used to working with Grib or netcdf.  Maybe someone could help?  In the .dat file, I believe the 3 columns are Y,X, and either 0 (no oil) or 16777215 for oil.  I am not sure why the converter picked that number.  Thanks an advance for the help!
>
> -Nick
>
> ----- Original Message -----
> From: Jennifer Adams <jma at cola.iges.org>
> Date: Tuesday, December 21, 2010 10:48 am
> Subject: Re: [gradsusr] Geotiffs in Grads
> To: GrADS Users Forum <gradsusr at gradsusr.org>
>
>> Hi, Nick --
>> What you are asking for is a 'dtype geotiff' which does not exist
>> in
>> GrADS. Turning the information in a geotiff file into a grid of
>> values
>> that you can analyze with GrADS is a job for customized stand-alone
>>
>> code. You may find some useful utilities to help you get started in
>>
>> the libgeotiff distribution.
>> --Jennifer
>>
>>
>> On Dec 21, 2010, at 10:29 AM, Nick Heath wrote:
>>
>> > Hi everyone,
>> >
>> > I am working with oil spill data, and I need a way to display the
>>
>> > oil in my model.  I have geotiffs of the oil locations and I was
>> > wondering if there is any way to read those into Grads.  I also
>> have
>> > the locations in .gif files.  If that is not possible, does
>> anyone
>> > have any good ideas of how I could make a "blob" of oil that I
>> could
>> > apply equations to (such as a wind drift to watch how it moved
>> > through time)?
>> >
>> > Here is the config of the Grads I'm using:
>> >
>> > Config: v2.0.a8 little-endian readline printim grib2 netcdf hdf4-
>> sds
>> > hdf5 opendap-grids,stn geotiff shapefile
>> > Grid Analysis and Display System (GrADS) Version 2.0.a8
>> > Copyright (c) 1988-2010 by Brian Doty and the
>> > Institute for Global Environment and Society (IGES)
>> > This program is distributed WITHOUT ANY WARRANTY
>> > See file COPYRIGHT for more information.
>> >
>> > Built Fri Mar 26 10:24:10 EDT 2010 for x86_64-unknown-linux-gnu
>> >
>> > This version of GrADS has been configured with the following
>> options:>  o Built on a LITTLE ENDIAN machine
>> >  o Athena Widget GUI DISABLED
>> >  o Command line editing ENABLED
>> >      http://tiswww.case.edu/php/chet/readline/rltop.html
>> >  o printim command for image output ENABLED
>> >      http://www.zlib.net
>> >      http://www.libpng.org/pub/png/libpng.html
>> >      http://www.libgd.org/Main_Page
>> >  o GRIB2 interface ENABLED
>> >      http://www.ijg.org
>> >      http://www.ece.uvic.ca/~mdadams/jasper
>> >      http://www.nco.ncep.noaa.gov/pmb/codes/GRIB2
>> >      g2clib-1.1.8
>> >  o NetCDF interface ENABLED
>> >      http://www.unidata.ucar.edu/software/netcdf
>> >      netcdf 4.1.1-rc2 of Mar 23 2010 09:31:58 $
>> >  o OPeNDAP gridded data interface ENABLED
>> >  o OPeNDAP station data interface ENABLED
>> >      http://iges.org/grads/gadoc/supplibs.html
>> >      libgadap 2.0
>> >  o HDF4 and HDF5 interfaces ENABLED
>> >      http://hdfgroup.org
>> >      HDF 4.2r3
>> >      HDF5 1.8.4
>> >  o GeoTIFF and KML output ENABLED
>> >      http://www.libtiff.org
>> >      http://geotiff.osgeo.org
>> >  o Shapefile interface ENABLED
>> >      http://shapelib.maptools.org
>> >
>> > Thanks for the help!
>> >
>> > Nick
>> > _______________________________________________
>> > gradsusr mailing list
>> > gradsusr at gradsusr.org
>> > http://gradsusr.org/mailman/listinfo/gradsusr
>>
>> --
>> Jennifer M. Adams
>> IGES/COLA
>> 4041 Powder Mill Road, Suite 302
>> Calverton, MD 20705
>> jma at cola.iges.org
>>
>>
>>
>>
>
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>



-- 
*************************************************
Dr. Ya-Qiang Wang
Centre for Atmosphere Watch and Services (CAWAS), CMA
Chinese Academy of Meteorological Sciences (CAMS)
46, Zhong-Guan-Cun South Avenue
Beijing, 100081
China

yaqiang.wang at gmail.com
**************************************************