I understand, thank you for the explanation.
That means I'm in a situation I don't know how to handle properly.
I have a tiff raster with a tfw file attached. The tfw, as you probably know, hasn't CRS information, only information about the raster's position. So I thought I had to force a CRS because Geoserver hasn't a secure way to guess it. Infact my raster is in EPSG:3003 CRS.
Since Geoserver keeps forcing 4326 as CRS (pressing the lookup button), I think it is processing the raster in that CRS, as you stated, even if I force my correct SRID. Is it right?
If that is the case, I think it cannot process well my raster and infact I'm not able to get it displayed properly (it shows a white png, when I call it from the WMS interface).
Have I to georeference my raster in WGS84 to go well? Or maybe using geotiff (which, if I'm not wrong, does contain CRS information)?
Thanks a lot,
Fabio
-----Messaggio originale-----
Da: Andrea Aime [mailto:aaime@anonymised.com]
Inviato: lunedì 19 febbraio 2007 15.13
A: Fabio Da Soghe
Cc: 'geoserver-users@lists.sourceforge.net'
Oggetto: Re: [Geoserver-users] Problems with EPSG lookupFabio Da Soghe ha scritto:
> I'm here again.
>
> On Geoserver 1.5.0-RC1 there seems to be something strange with EPSG
> management.
>
> When I create a new Coverage (or edit an existing FeatureType) I'm
> not able to insert my preferred EPSG code.
>
> In the FeatureType Editor page I insert my EPSG code (in my case,
> 3003) and press the "Lookup SRS" button. After a (strange) while I
> get the number 3003 overwritten with "UNKNOWN" and the SRS WKT is:
> "Could not find a definition for: EPSG:UNKNOWN".Nope, the lookup SRS button is there to make Geoserver compare
native data SRS information (if there is any) against the
EPSG database and find a matching EPSG number.
This is not done automatically because it requires several
seconds to match native CRS parameters ataIf your data does not have native information, or if it's not
found, you'll get UNKNOWN.
Nothing prevents you from setting your own, just don't re-repress
"lookup SRS" after that
Yet, if you set 3003 and lookup srs returns 4326, it means your
coverage contains 4326 as native CRS, not 3003.
Geoserver won't allow you to force a different SRS, if you provide
a different one, data will be reprojected from the native one to the
declared one, from 4326 to 3003, in your case. This behaviour is
needed to handle data whose native CRS is not matched at all
in the EPSG
database.
The declared CRS will be "forced" only if your data does not have one,
in that case we'll assume data has the same CRS as the declared one.It's a tricky issue, as a general approach we decided to trust more
the data than the user since most of the users around do not even know
what an EPSG code is, let alone WKT, Bursa Worlf parameters and the
like. I guess those who know should be able to fix their data, should
it contain wrong SRS information.Hope this helps
Cheers
Andrea
