Thanks Andrea for the explanation. My original thinking was more in line
with your last case. I'm dealing with 3 different projections - cadaster,
topo and data collected using gps. I need to mix and match them.

But my problem was that 4326 as native will not reproject to a different
declared projection in geoserevr 2.0.2 on Ubuntu 10.04.

Regards

*Hilmy*


On Wed, Apr 27, 2011 at 3:51 AM, Andrea Aime
<andrea.a...@geo-solutions.it>wrote:

> On Tue, Apr 26, 2011 at 8:38 PM, Ian Turton <ijtur...@gmail.com> wrote:
> > On 26 April 2011 14:33, Hilmy Hashim <hil...@gmail.com> wrote:
> >> Thanks Ian, I see what you mean and it appears to work.
> >> But isn't the SRS Handling option "Reproject Native to Declared" meant
> for
> >> changing the srs of your native data?
> >
> > Only when your data is lying about it's projection.
>
> It's more complicated that that.
>
> There are three options:
> - leave native: to be used when you want to lie to your user, but want
> to actually keep on using the math of the original projection. Rarely
> ever needed
> - force declared: to be used when the native projection is missing or
> wrong, will make the native be completely ignored. Works fine as a
> default too (that is, when native and declared are the same)
> - reproject from native: this actually has two valid usages.
>  The first one, for which this was born, is when you have a legit
> native SRS that cannot be matched to any official EPSG code. It's
> probably some custom projection or some obscure/old national
> projection.
>  By using "reproject to declared" you can choose a valid EPSG code to
> be advertised, and publish your data as if it was in that projection.
>  The other legit case is then one mentioned by Jukka, you have
> standard WFS 1.0 clients that cannot use the srsName parameter (which,
> in WFS 1.0, is to be considered a GeoServer vendor extension) but you
> still want to provide them a layer in one or more projections (WFS 1.0
> wise). You can do that by publishing the same layer multiple times
> doing the "reproject from native" dance, changing each time the
> declared srs.
>
> Makes sense?
>
> Cheers
> Andrea
>
> --
> -------------------------------------------------------
> Ing. Andrea Aime
> GeoSolutions S.A.S.
> Tech lead
>
> Via Poggio alle Viti 1187
> 55054  Massarosa (LU)
> Italy
>
> phone: +39 0584 962313
> fax:      +39 0584 962313
>
> http://www.geo-solutions.it
> http://geo-solutions.blogspot.com/
> http://www.youtube.com/user/GeoSolutionsIT
> http://www.linkedin.com/in/andreaaime
> http://twitter.com/geowolf
>
> -------------------------------------------------------
>
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