Re: [Geotools-devel] Questions about DataSource and CoordinateSystem

[Cameron S. <csh...@bi...>]

On Sunday 29 September 2002 07:22, Martin Desruisseaux wrote:

>
> May proposal is to keep every Feature in their "native" coordinate
> system (we do not reproject them in DataSource). This means that each
> Feature must know its own CoordinateSystem.
>
> When an area is requested from a DataSource in whatever coordinate
> system, the DataSource will compare the requested area's coordinate
> system with each Feature's CoordinateSystem, and project the area
> individually when necessary.
>
> 	What do you think?

Martin,
I think you are right here.  Feature should store CoordinateSystem instead of 
DataSource.  And the consequence of this is that if you query a DataSource 
based on Extent, then you also need to provide the CoordinateSystem as well.

So what I propose to do is ceate a GeometryFilter(BBox, CoordinateSystem) 
constructor which can then be passed into the DataSource query.

--
On another note, I think we should create a DefaultDataSource which other 
DataSource objects extend.  (This may be a problem for GMLDataSource which 
already extends XMLFilterImpl.

-- 
Cameron Shorter              http://cameron.shorter.net
Open Source Developer        http://mapbuilder.sourceforge.net
Senior Software Engineer http://www.adi-limited.com/