Re: [Geotools-devel] Geometry and Render, Geometry and Expression Improvements

[Justin D. <jde...@op...>]

Jody Garnett wrote:
> Jody Garnett wrote:
>> Thanks Martin this is good stuff;
>>
>> Thinking about integration:
>> #1 we will need a "decimation" interface from Object -> Shape in order
>> for the renderer to function with any Geometry implementation (not
>> this is already being considered by the JPOX crew as a way to let
>> Oracle Geometry implementations play directly)
>>   
> This one seems better the longer I think about it; after the next uDig
> release I will try and thrash this
> out with Jesse I guess.
>> #2 we will need to pull the same game we did for Literal support; that
>> is define an extension that lets the Spatial Filter functions work
>> against Object
>>   
> I had enough of a brainstorm to right this up:
> -
> http://docs.codehaus.org/display/GEOTOOLS/Expression+Improvements#ExpressionImprovements-GeometryFilters
> 
> 
> Justin have a read over; the expression evaluation context solution
> using Class is a bit weak. If we could include more
> context (CRS in this case) we would be projection safe.

So basically you are talking about making the context a Hints instance.
I am not sure I like this approach as it tends to spiral out of control
with no constraint as you can add anything to the hints and it may or
may not be regarded.

I can think of two additional approaches for the crs problem which are
more explicit.

1. Create a "ReprojectionExpression" (for lack of a better name) which
will take another expression and ensure it is evaluated and reprojected
accordingly.

2. Make spatial expressions know about crs, and have part of their
contract be that things should be reprojected into the set CRS.



> 
> Jody
>> I would ask Justin to comment (please) on the second point; and will
>> note the existing fix for Expression.evaulate( Object, class ) allows
>> the spatial functions to "pull" down JTS Geomertry as the system has
>> been taught how to convert - for the wrapping based solution this is
>> an easy win (make a converter to unpack and then everything will
>> work). This may let you put off point #2.
>>
>> Cheers,
>> Jody
>>
>>  
>>> I commited Sanjay Jena's work on ISO 19107 implementation:
>>>
>>> http://svn.geotools.org/geotools/trunk/gt/modules/unsupported/geometry/
>>>
>>> This a work in progress, and is not yet part of the Maven build. I
>>> will work on the Maven configuration later.
>>>
>>> Note to Sanjay: I renamed the following packages:
>>>
>>> org.geotools.geometry.featgeom
>>> geometry.featgeom
>>>
>>> into
>>>
>>> org.geotools.geometry.iso
>>>
>>> Since "featgeom" is somewhat redundant with "geometry", and "iso" is
>>> complementary with "jts" (an other org.geotools.geometry subpackage).
>>> However we may drop the "iso" name completly in a future version and
>>> put the classes straight at the "org.geotools.geometry" level; I'm
>>> not yet sure and for sure it will depends if you agree or not :).
>>>
>>> I also moved the "lineSegmentsData.dat" and "lineStringData.dat"
>>> files into the
>>> "src/test/resources/org/geotools/geometry/iso/test-data" directory.
>>> However I don't know which code to change for that, since I didn't
>>> any found "lineFooData.dat" occurence in the test directory.
>>>
>>> Apart for the package name changes, I didn't changed anything to the
>>> code.
>>>
>>> Thanks a lot for sharing your work!!
>>>
>>>     Martin
>>>
>>>
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-- 
Justin Deoliveira
jde...@op...
The Open Planning Project
http://topp.openplans.org