Hi Don,
We have a NetCDF-Java GeoTIFF IOSP that we use internally at CIDA to access
GeoTIFF WCS responses using the NetCDF-Java CDM. I've hesitated to release it
externally due to the number dependencies it requires and the rather, err,
hack-ish, EPSG DB I'd implemented yo back it. To provide reasonable support
for GeoTIFFs that one may see in-the-wild the tool does need a access to a full
EPSG DB to resolve all the potential CRS *and* their components. GeoTIFFs have
a rich mechanism for describing CRS which require implementations to have
access to a lot that CRS data. I'd planned to provide hooks for EPSG lookups
using GeoTools or Geotk but never found the time.
Now that NetCDF-Java is mavenized the dependency tracking/resolution for
developers that want to use this should be a little easier. Maybe I can clean
the GeoTIFF IOSP up and put it out there...
Tom
On Jun 12, 2011, at 12:53 PM, Don Murray wrote:
> Hi Tom-
>
> I am interested in what you describe below and am wondering if anyone else is
> working on a GeoTools to netCDF CDM Scientific Data types library. In
> particular, I'd like to take advantage of GeoTools' GeoTIFF capabilities and
> would like to read a GeoTIFF into a CDM GeoGrid so I could view/manipulate
> them in the Integrated Data Viewer (IDV). A key piece of that would be to
> support the projections which I believe is what you are describing below.
>
> Am I reading that correctly and/or is anyone else working on a GeoTools to
> netCDF library?
>
> Thanks.
>
> Don
>
> On 6/11/11 9:54 PM, Tom Kunicki wrote:
>> As a follow up to my posting of the NetCDF-Java/CF projection to
>> GeoTools/GeoAPI converter utility posting. As background we are
>> doing geoprocessing of vector geometries obtained from Shapefiles or
>> GML (often via WFS). Given the large number of CRS that maybe used
>> with these vector geometries (relative to what's available with CF)
>> and the desire to perform the calculations in the CRS used with the
>> vector geometries we generate a GeoTools/GeoAPI CRS instance so that
>> we can transform the CF grids into the vector geometry CRS.
>>
>> An issue we have with NetCDF-Java is that not the NetCDF-Java
>> Projection instance isn't passing through the ellipsoid parameters
>> for Projection implementations that don't have transformation to
>> ellipsoids implemented (even though the CF spec. Ideally we could
>> extract these from Projection.getProjectionParameters() so that we
>> can generate a fully parameterized GeoAPI CoordinateReferenceSystem
>> instance which will then use these parameters. Given the abstraction
>> of GridDatatype/GridCoordSystem is very difficult to extract these
>> parameters from the original CF grid_mapping. Could we get these
>> parameters (semi_major_axis, semi_minor_axis and inverse_flattening)
>> in the Projection instance for all Projections if they are in the
>> grid_mapping for the grid?
>>
>> One thing i've been hoping to do is implement a
>> ProjectionProviderFactory type architecture for NetCDF-Java that
>> would allow the implementation of NetCDF-Java Projection instances
>> using GeoTools or Geotk. One could register a factory using a
>> service registration mechanism then get back Projection
>> implementations back by their API of choice. This would remove the
>> need for NetCDF-Java to re-implement projection transformations that
>> are already implemented in GeoTools or Geotk. The CRSUtility class I
>> provided earlier could be the foundation/crosswalk for a
>> GeoToolsProjectionProviderFactory. One can easily generate
>> transforms and their inverses once the CoordinateReferenceSystem
>> instance is generated. These transforms can the be wrapped in a
>> NetCDF-Java Projection instance This would also allow CF to
>> incorporate new projections and minimize implementation time in
>> NetCDF-Java.
>>
>> Tom Kunicki Center for Integrated Data Analytics U.S. Geological
>> Survey 8505 Research Way Middleton, WI 53562
>>
>>
>>
>> _______________________________________________ netcdf-java mailing
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>
> --
> Don Murray
> NOAA/ESRL/PSD and CIRES
> 303-497-3596
> http://www.esrl.noaa.gov/psd/people/don.murray/
>
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Tom Kunicki
Center for Integrated Data Analytics
U.S. Geological Survey
8505 Research Way
Middleton, WI 53562
