[Geotiff] I am a newbie who has a need to know

[Frank Warmerdam]

Wells, John - FS wrote:
> Hi,
>  
> I am producing geographic data using a variety of platforms for a 
> research project in Global climate change.  I am not a student and this 
> is sponsored by the Nature Conservancy.  The project will result in a 
> large number of files containing atmospheric and ecotone information.  
> The client has asked that the data be in Geotiff format.  We have never 
> used Geotiff.  I have not written programs to convert from one data type 
> to another although I know with effort I can, but we had hoped a module 
> or conversion program might already exist that would convert our data to 
> Geotiff.  After reading on this listserv and other web locations about 
> Geotiff I wonder if that is possible.  Since I know so little I don't 
> know how one adds georeferencing tags to a standard tiff file.  Is there 
> a utility that does this.  I should mention that our data is in NetCDF 
> and the most common gis we use is GRASS.  Any help or advice you can 
> offer would be appreciated?  I will keep reading.

John,

If you have your data in GRASS, you can use r.out.tiff or r.out.gdal to
export to GeoTIFF.  If you have your data external to GRASS in NetCDF,
you can try converting it to GeoTIFF using gdal_translate.   How well
this works will depend on how well GDAL supports your netcdf dataset.

In particular, you may find you need to apply coordinate system and perhaps
extents information as part of the translation to GeoTIFF if you don't
have netcdf metadata that GDAL can understand.

For example, the following would assign a WGS84 geographic coordinate
system and upper/left, lower/right bounds for a dataset as part of the
conversion process.

   gdal_translate in.nc out.tif -a_srs WGS84 -a_ullr -180 90 180 -90

GDAL needs to be explicitly built with netcdf support.  You may find
it helpful to use the FWTools binaries which include netcdf support (at
least on linux I think).

   http://fwtools.maptools.org/

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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