We actually ran into a similar problem last year with 2D rendering.
We put a special case in the renderer to go from 3D to 2D (it is a 2D
renderer). What it would do (if required) was translate to "any 3d" to
WGS84-3D. Then it would drop the coordinates to make it WGS84-2D and then
finally transform into the requested 2D space for drawing.
So if you had a 3D renderer it could take similar steps (doing your height
look up in place of dropping the coordinates above).
--
Jody
Jody Garnett
On Wed, Jun 25, 2014 at 12:58 AM, Eric W. Anderson <ander...@cs.cmu.edu>
wrote:
> So, I figured out what's going on in my particular case, and I could
> relatively-cleanly add a "Elevation Provider" to supply Z dimension info,
> and
> an Elevation Provider Factory to supply it, and put support for that into
> ReferencingFactoryFinder.
>
> The question then becomes: Where would you want the logic for "when should
> GeoTools try to use this" go? Right now, GeoTools' default logic (in
> DefaultCoordinateOperationFactory) seems to be happy as a clam until it
> tries
> to SwapAndScaleAxis from a 2D CS to a 3D CS, and then it borks. I could
> special-case this particular logic, but I have to imagine the "I want to do
> 2D->3D" case could come up in other paths, too. Any suggestions?
>
> Thanks,
> Eric
>
> Thus spake Jody Garnett (jody.garn...@gmail.com):
>
> > Nice turtles all the way down reference.
> > I figured this out once for a change request, it has diagrams if that
> > helps you find your way:
> > [1]
> http://docs.codehaus.org/display/GEOTOOLS/Improve+CRSAuthority+Concurrency+Caching+and+Connection+Use
> > The indirection is mostly caused by a "need for speed" - they can be
> > expensive to create so we cache everything we can with weak
> references,
> > but that was not good enough so we hard reference the most popular 10
> or
> > something ...
> > I did not look carefully at MathTransformFactory use, I would
> recommend
> > stepping through with a debugger (a great way to figure things out
> when
> > there is this much setup and indirection involved). Note some of the
> other
> > CoordinateReferenceSystems end up being backed by their own large
> datasets
> > (Grid Shift files). I have never registered an additional
> MathTransform
> > myself, but the design does allow for it.
> > Jody Garnett
> >
> > On Tue, Jun 24, 2014 at 1:38 AM, Eric W. Anderson <[2]
> ander...@cs.cmu.edu>
> > wrote:
> >
> > Hi All,
> >
> > Thanks for the help. I looked at this a bit, and I'm trying to
> figure
> > out
> > exactly what's going on. There seems to be a nearly-endless chain
> of
> > indirection here, looking for providers of implementations of pools
> of
> > registries of sets of plugins of finders of factories of ...
> >
> > Is there somewhere -- either in the code or the documentation --
> where
> > the
> > logic of "how to find or construct a transform from coordinate
> system A
> > to
> > coordinate system B" is located, or is it turtles all the way down?
> > DefaultCoordinateOperationFactory is the closest thing I've found.
> >
> > Thanks,
> > Eric
> >
> > Thus spake Jody Garnett ([3]jody.garn...@gmail.com):
> > > There is a bunch of factories for this stuff:
> > >
> > [1][4]
> http://docs.geotools.org/latest/userguide/library/referencing/internal.html
> > > I am used to handling this as a geometry processing task in
> other
> > systems
> > > (rather than a math transform)....
> > > i.e. use either a process or a function that geometry in and a
> DEM
> > in, and
> > > "Drapes" the geometry over the DEM returning a new geometry.
> > >
> > - [2][5]
> http://docs.geotools.org/latest/userguide/tutorial/function.html
> > >
> > - [3][6]
> http://docs.geotools.org/latest/userguide/tutorial/process.html
> > > Those are worth going over anyways as they introduce how
> geotools
> > > factories work.
> > > --
> > > Jody Garnett
> > >
> > > On Wed, Jun 18, 2014 at 4:06 AM, Eric W. Anderson
> > <[4][7]ander...@cs.cmu.edu>
> > > wrote:
> > >
> > > What would I have to do to add this? Or, put slightly
> > differently,
> > > what's the
> > > current process by which findMathTransform() looks for
> > conversions, and
> > > how can
> > > I tell it about a new one?
> > >
> > > (I know I could just hack in some code to do what I want, but
> > that would
> > > be
> > > ugly.)
> > >
> > > Thanks,
> > > Eric
> > >
> > > Thus spake Andrea Aime ([5][8]andrea.a...@geo-solutions.it):
> > > > On Fri, Jun 13, 2014 at 10:36 PM, Eric W. Anderson
> > > > <[1][6][9]ander...@cs.cmu.edu> wrote:
> > > >
> > > > Hi All,
> > > >
> > > > I'm using Geotools, and I need to convert coordinates
> > between 2D
> > > and 3D
> > > > coordinate reference systems. I recognize that
> there's no
> > > > universally-correct way to do this: 2D -> 3D means
> "making
> > up" a
> > > Z
> > > > coordinate, and 3D -> 2D means losing information.
> But, is
> > there
> > > some
> > > > way to teach Geotools that, in my particular context,
> I
> > want to
> > > use a
> > > > specific transformation. E.g.:
> > > >
> > > > +-----+ +-----+
> > > > | | --- Z = 15 ---> | |
> > > > | 2D | | 3D |
> > > > | | <-- drop Z ---- | |
> > > > +-----+ +-----+
> > > > I know I can transform any particular coordinate
> manually
> > this
> > > way, but
> > > > I'd like to integrate it so this Just Works. e.g. I
> can do
> > > > CRS.findMathTranform(a, b) and if a is convertible to
> my
> > 2D CRS,
> > > and my
> > > > 3D CRS is convertible to b, it works.
> > > >
> > > > No. The 3D -> 2D path is normally supported, but the 2D
> ->
> > 3D never
> > > is as
> > > > far as I remember.
> > > > That said, if all you want is adding an extra static
> > ordinate, it
> > > should
> > > > not be too hard to do it yourself.
> > > > I guess it could be interesting to have some tooling in
> > geotools
> > > that
> > > > given a 2D geometry and a helper object, would add the
> 3rd
> > > ordinate, where
> > > > the helper might look like:
> > > > interface ElevationProvider() {
> > > > double getElevation(DirectPosition2D pos);
> > > > }
> > > > which then the client would implement in different ways,
> > e.g.,
> > > fixed
> > > > value, or DEM sampling.
> > > > As usual, it's a matter of one having enough
> time/funding to
> > > discuss the
> > > > evolution in the dev mailing list,
> > > > implement it, and merge it.
> > > > Cheers
> > > > Andrea
> > > >
> > > > --
> > > > ==
> > > > GeoServer Professional Services from the experts! Visit
> > > > [2][7][10]http://goo.gl/NWWaa2 for more information.
> > > > ==
> > > > Ing. Andrea Aime
> > > > @geowolf
> > > > Technical Lead
> > > > GeoSolutions S.A.S.
> > > > Via Poggio alle Viti 1187
> > > > 55054 Massarosa (LU)
> > > > Italy
> > > > phone: [8][11]+39 0584 962313
> > > > fax: [9][12]+39 0584 1660272
> > > > mob: [10][13]+39 339 8844549
> > > > [3][11][14]http://www.geo-solutions.it
> > > > [4][12][15]http://twitter.com/geosolutions_it
> > > > -------------------------------------------------------
> > > >
> > > > References
> > > >
> > > > Visible links
> > > > 1. mailto:[13][16]ander...@cs.cmu.edu
> > > > 2. [14][17]http://goo.gl/NWWaa2
> > > > 3. [15][18]http://www.geo-solutions.it/
> > > > 4. [16][19]http://twitter.com/geosolutions_it
> > > --
> > > Eric W. Anderson Computer Science
> > Department
> > > [17][20]ander...@cs.cmu.edu
> Carnegie
> > Mellon
> > > University
> > > phone: [18][21]+1-412-268-1908
> > Gates-Hillmann Center
> > > 6005
> > >
> > > PGP key fingerprint:
> > > D3C5 D6FF EDED 9F1F C36D 53A3 74B7 53A6 3C74 5F12
> > >
> >
>
> ------------------------------------------------------------------------------
> > > HPCC Systems Open Source Big Data Platform from LexisNexis
> Risk
> > > Solutions
> > > Find What Matters Most in Your Big Data with HPCC Systems
> > > Open Source. Fast. Scalable. Simple. Ideal for Dirty Data.
> > > Leverages Graph Analysis for Fast Processing & Easy Data
> > Exploration
> > > [19][22]http://p.sf.net/sfu/hpccsystems
> > > _______________________________________________
> > > GeoTools-GT2-Users mailing list
> > > [20][23]GeoTools-GT2-Users@lists.sourceforge.net
> > >
> > [21][24]
> https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
> > >
> > > References
> > >
> > > Visible links
> > > 1.
> > [25]
> http://docs.geotools.org/latest/userguide/library/referencing/internal.html
> > > 2.
> > [26]
> http://docs.geotools.org/latest/userguide/tutorial/function.html
> > > 3.
> > [27]http://docs.geotools.org/latest/userguide/tutorial/process.html
> > > 4. mailto:[28]ander...@cs.cmu.edu
> > > 5. mailto:[29]andrea.a...@geo-solutions.it
> > > 6. mailto:[30]ander...@cs.cmu.edu
> > > 7. [31]http://goo.gl/NWWaa2
> > > 8. file:///tmp/tel:%2B39%200584%20962313
> > > 9. file:///tmp/tel:%2B39%200584%201660272
> > > 10. file:///tmp/tel:%2B39%20%C2%A0339%208844549
> > > 11. [32]http://www.geo-solutions.it/
> > > 12. [33]http://twitter.com/geosolutions_it
> > > 13. mailto:[34]ander...@cs.cmu.edu
> > > 14. [35]http://goo.gl/NWWaa2
> > > 15. [36]http://www.geo-solutions.it/
> > > 16. [37]http://twitter.com/geosolutions_it
> > > 17. mailto:[38]ander...@cs.cmu.edu
> > > 18. file:///tmp/tel:%2B1-412-268-1908
> > > 19. [39]http://p.sf.net/sfu/hpccsystems
> > > 20. mailto:[40]GeoTools-GT2-Users@lists.sourceforge.net
> > > 21.
> > [41]https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
> > --
> > Eric W. Anderson Computer Science
> Department
> > [42]ander...@cs.cmu.edu Carnegie Mellon
> > University
> > phone: [43]+1-412-268-1908 Gates-Hillmann
> Center
> > 6005
> >
> > PGP key fingerprint:
> > D3C5 D6FF EDED 9F1F C36D 53A3 74B7 53A6 3C74 5F12
> >
> > References
> >
> > Visible links
> > 1.
> http://docs.codehaus.org/display/GEOTOOLS/Improve+CRSAuthority+Concurrency+Caching+and+Connection+Use
> > 2. mailto:ander...@cs.cmu.edu
> > 3. mailto:jody.garn...@gmail.com
> > 4.
> http://docs.geotools.org/latest/userguide/library/referencing/internal.html
> > 5. http://docs.geotools.org/latest/userguide/tutorial/function.html
> > 6. http://docs.geotools.org/latest/userguide/tutorial/process.html
> > 7. mailto:ander...@cs.cmu.edu
> > 8. mailto:andrea.a...@geo-solutions.it
> > 9. mailto:ander...@cs.cmu.edu
> > 10. http://goo.gl/NWWaa2
> > 11. file:///tmp/tel:%2B39%200584%20962313
> > 12. file:///tmp/tel:%2B39%200584%201660272
> > 13. file:///tmp/tel:%2B39%20%C2%A0339%208844549
> > 14. http://www.geo-solutions.it/
> > 15. http://twitter.com/geosolutions_it
> > 16. mailto:ander...@cs.cmu.edu
> > 17. http://goo.gl/NWWaa2
> > 18. http://www.geo-solutions.it/
> > 19. http://twitter.com/geosolutions_it
> > 20. mailto:ander...@cs.cmu.edu
> > 21. file:///tmp/tel:%2B1-412-268-1908
> > 22. http://p.sf.net/sfu/hpccsystems
> > 23. mailto:GeoTools-GT2-Users@lists.sourceforge.net
> > 24. https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
> > 25.
> http://docs.geotools.org/latest/userguide/library/referencing/internal.html
> > 26. http://docs.geotools.org/latest/userguide/tutorial/function.html
> > 27. http://docs.geotools.org/latest/userguide/tutorial/process.html
> > 28. mailto:ander...@cs.cmu.edu
> > 29. mailto:andrea.a...@geo-solutions.it
> > 30. mailto:ander...@cs.cmu.edu
> > 31. http://goo.gl/NWWaa2
> > 32. http://www.geo-solutions.it/
> > 33. http://twitter.com/geosolutions_it
> > 34. mailto:ander...@cs.cmu.edu
> > 35. http://goo.gl/NWWaa2
> > 36. http://www.geo-solutions.it/
> > 37. http://twitter.com/geosolutions_it
> > 38. mailto:ander...@cs.cmu.edu
> > 39. http://p.sf.net/sfu/hpccsystems
> > 40. mailto:GeoTools-GT2-Users@lists.sourceforge.net
> > 41. https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
> > 42. mailto:ander...@cs.cmu.edu
> > 43. file:///tmp/tel:%2B1-412-268-1908
>
> --
> Eric W. Anderson Computer Science Department
> ander...@cs.cmu.edu Carnegie Mellon University
> phone: +1-412-268-1908 Gates-Hillmann Center 6005
>
> PGP key fingerprint:
> D3C5 D6FF EDED 9F1F C36D 53A3 74B7 53A6 3C74 5F12
>
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