Re: [netcdf-java] ncWMS and ellipsoid-support in CF-1.2

Hi all:

we found a serious defect in the GRIB reader that returns potentially 
wrong data, so we now dont expect a stable release until september (i am 
on vacation right now). the current snapshot / release fixes GRIB but 
hasnt yet propagated the fix to FMRC. if you are not using GRIB FMRC 
feature, testing with the current release would be most welcome.

john

TDS 4.2 will include CDM 4.2.

Heiko Klein wrote:
> Hi John, hi Jonathan,
>
> I just had a look at the latest netcdf-java 4.2beta and I don't see 
> any problems with respect to the ellipsoid-support for 
> transverse_mercator and stereographic files.
>
>
> To reduce the number of required updates to our operational 
> thredds-servers, I would like to ask some question about your roadmap:
>
> When will thredds-4.2 be declared stable (approx.)?
> Will thredds-4.2 include netcdf-java 4.2?
>
> The myOcean project/Jonathan asks us to install the current 
> thredds-4.2 soon (August/September?). Can we wait for an official 
> stable version of thredds-4.x with the ellipsoid support, or should we 
> just follow the myOcean-requested updates?
>
> Best regards,
>
> Heiko
>
> On 2010-08-12 17:39, Unidata netCDF Java Support wrote:
> > these should be in the latest 4.2 (beta) cdm. please let me know if 
> > you see any problems. thanks again.
> >
> > john
> >
> > > Hi Heiko:
> > >
> > > These look great, i will integrate into 4.2 asap. thanks a lot!
> > >
> > > John
> > >
> > > > Hi John,
> > > >
> > > > I found some time to include jhlabs code for Stereographic and
> > > > Transverse Mercator into ncSrc-4.2.zip . The Stereographic code had 
> > > > some
> > > > bugs, as you expected, and the TransverseMercator code worked well. 
> > > > The
> > > > files in unidataCommon include a main method with some smaller tests.
> > > >
> > > > I tested the code with toolsUI and the topography-files in
> > > > http://pastebin.met.no/p/c/file?id=8553484f24/topoFiles.zip
> > > > (those files will be automatically deleted in 14days)
> > > >
> > > > The stereograhpic files have a difference of approx. 5km in southern
> > > > Norway, while the UTM files have a difference of more than 10km there
> > > > comparing the spherical vs the ellipsoid version.
> > > >
> > > > I made a least effort approach when converting the code, so it's far
> > > > from well tested or beautiful. But I hope this code can make it to the
> > > > netcdf-java, if just as intermediate solution until the one or other
> > > > geo-api has been added.
> > > >
> > > > Best regards,
> > > >
> > > > Heiko
> > > >
> > > > On 2010-06-09 23:47, John Caron wrote:
> > > > > Hi Heiko:
> > > > >
> > > > > Im not sure how fast i can get to that. Do you have real datasets 
> > > > > with
> > > > > those projections?
> > > > >
> > > > > The proj4 code is from the jhlabs partial port at
> > > > >
> > > > > http://www.jhlabs.com/java/maps/proj/index.html
> > > > >
> > > > > The ones that ive already done are at
> > > > >
> > > > > http://svn.unidata.ucar.edu/repos/common/java/trunk/src/main/java/ucar/unidata/geoloc/projection/proj4/ 
> > > > >
> > > > >
> > > > >
> > > > > I should warn you that I have seen bugs in the Java, which i think is
> > > > > some automatic C/Java translater. I have been checking against the
> > > > > original C code. Also, theres a lot of modifications to be made to 
> > > > > make
> > > > > it compatible with our Projection class. Thats why the Geotools 
> > > > > API may
> > > > > be a better idea.
> > > > >
> > > > > BTW, Transverse Mercator on the ellipsoid i think is UTM, which we 
> > > > > have.
> > > > > So perhaps you only need Stereographic ?
> > > > >
> > > > > John
> > > > >
> > > > > > On 6/9/2010 7:08 AM, Heiko Klein wrote:
> > > > > > Hi John,
> > > > > >
> > > > > > when we discussed the issue of ellipsoid-support in netcdf-java 
> > > > > > back in
> > > > > > March in the mailing-list it went very fast to: use one or another
> > > > > > GeoAPI.
> > > > > >
> > > > > > This sounded to me like a lot of work for you. If you don't plan 
> > > > > > to do
> > > > > > this work in the near future (i.e. 2010), could you please send 
> > > > > > me the
> > > > > > proj4j source. Maybe I can try then to add ellipsoid support of
> > > > > > Stereographic and Transverse Mercator to netcdf-java (4.2) during 
> > > > > > summer.
> > > > > >
> > > > > > Best regards,
> > > > > >
> > > > > > Heiko
> > > > > >
> > > > > > On 2010-03-24 17:46, John Caron wrote:
> > > > > >
> > > > > > > Heiko Klein wrote:
> > > > > > >
> > > > > > > > Hi Jon,
> > > > > > > >
> > > > > > > > I just found some time to look at the source of netcdf-java 
> > > > > > > > 4.1. As far
> > > > > > > > as I can see, only some projections (LambertConformalConicEllipse,
> > > > > > > > AlbersEqualAreaEllipse, UTM) support ellipsoids, while the 
> > > > > > > > others use a
> > > > > > > > constant spherical earth with EARTH_RADIUS = 6371.229km
> > > > > > > >
> > > > > > > > In particular, Stereographic projection doesn't support 
> > > > > > > > ellipsoids, so
> > > > > > > > this explains the offset in my maps.
> > > > > > > >
> > > > > > > > Would be nice to have this assured by one of the 
> > > > > > > > unidata-developpers. I
> > > > > > > > mainly checked the ucar/unidata/geoloc/projection sources.
> > > > > > > >
> > > > > > > > Best regards,
> > > > > > > >
> > > > > > > > Heiko
> > > > > > > Yes, correct. We are slowly adding ellipsoid support, but only 
> > > > > > > after we
> > > > > > > have a sample dataset that uses them. We are porting code from 
> > > > > > > proj4,
> > > > > > > its rather time-consuming to get it right.
> > > > > > > if you have sample data where the ellipsoidal earth matters, 
> > > > > > > send it
> > > > > > > along, we'll get to it when we can. or, if you have resources and
> > > > > > > expertise to port the proj4j code, i could send that to you and 
> > > > > > > get you
> > > > > > > started.
> > > > > > >
> > > > > > > John
> > > > > > >
> > > > > > >
> > > > > > > > On 2010-03-10 14:38, Jonathan Blower wrote:
> > > > > > > >
> > > > > > > > > Hi Heiko,
> > > > > > > > >
> > > > > > > > > This is a good question.  ncWMS relies on netcdf-java for 
> > > > > > > > > converting
> > > > > > > > > coords to wgs84 lat lon, so I'm copying this to the mailing 
> > > > > > > > > list in
> > > > > > > > > the hope that someone can enlighten me about ellipsoid support 
> > > > > > > > > in the
> > > > > > > > > library.
> > > > > > > > >
> > > > > > > > > Cheers, Jon
> > > > > > > > >
> > > > > > > > > -----Original Message-----
> > > > > > > > > From: Heiko Klein<address@hidden>
> > > > > > > > > Sent: 09 March 2010 08:54
> > > > > > > > > To: Jonathan Blower<address@hidden>
> > > > > > > > > Subject: ncWMS and ellipsoid-support in CF-1.2
> > > > > > > > >
> > > > > > > > > Hi Jon,
> > > > > > > > >
> > > > > > > > > I currently try to visualize some satellite ice-maps over the
> > > > > > > > > north-pole
> > > > > > > > > with ncWMS, but the data seems to be displaced by some 10-30km
> > > > > > > > > compared
> > > > > > > > > with the land-maps (generated by mapserver).
> > > > > > > > >
> > > > > > > > > While geo-tools and therefore ncWMS support lots of coordinate
> > > > > > > > > reference
> > > > > > > > > systems for the presented maps, the support for ellipsoids was 
> > > > > > > > > only
> > > > > > > > > added to CF-1.2. Do you know if ncWMS already supports the CF-1.2
> > > > > > > > > features like semi_major_axis/semi_minor_axis for input-files, 
> > > > > > > > > or does
> > > > > > > > > it assume the CF-1.0 spherical earth with 6371km radius?
> > > > > > > > >
> > > > > > > > > Best regards,
> > > > > > > > >
> > > > > > > > > Heiko
> > > > > > > > _______________________________________________
> > > > > > > > netcdf-java mailing list
> > > > > > > > address@hidden
> > > > > > > > For list information or to unsubscribe, visit:
> > > > > > > > http://www.unidata.ucar.edu/mailing_lists/
> > > >
> > > > --
> > > > Dr. Heiko Klein                              Tel. + 47 22 96 30 00
> > > > Development Section / IT Department          Fax. + 47 22 69 63 55
> > > > Norwegian Meteorological Institute           http://www.met.no
> > > > P.O. Box 43 Blindern  0313 Oslo NORWAY
> >
> >
> > Ticket Details
> > ===================
> > Ticket ID: UMF-635548
> > Department: Support netCDF Java
> > Priority: Critical
> > Status: Closed