Hi Tom-
On 6/12/11 12:39 PM, Tom Kunicki wrote:
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...
That would be great if you could.
Don
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
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-- Don Murray NOAA/ESRL/PSD and CIRES 303-497-3596
http://www.esrl.noaa.gov/psd/people/don.murray/
_______________________________________________ netcdf-java mailing
list netcdf-java@xxxxxxxxxxxxxxxx For list information or to
unsubscribe, visit: http://www.unidata.ucar.edu/mailing_lists/
Tom Kunicki Center for Integrated Data Analytics U.S. Geological
Survey 8505 Research Way Middleton, WI 53562
--
Don Murray
NOAA/ESRL/PSD and CIRES
303-497-3596
http://www.esrl.noaa.gov/psd/people/don.murray/
