[mapserver-users] multiple transparent colours

[Rahkonen Jukka]

Hi,

Just came into my mind that I have had problems with OFFSITE and tileindex. It makes the desired pixel value transparent with WMS but not with WCS. At least is was so in the past. I have not produced WCS lately. The workaround was to make a VRT file from with gdalbuildvrt and use that as input for the WCS mapfile.  That way nodata worked as it should and we got proper images out of WCS even with warped source images. I am not sure if I ever made a ticket from that. Perhaps not or then just nobody ever reacted.

So I suppose that "OFFSITE AUTO" happens already if you use VRT as input instead of tileindex. I have not seen big difference in speed between tileindex and VRT. However, I use normally tileindex system because I can open and manage the index files with GIS programs.

-Jukka Rahkonen-

Stephen Woodbridge wrote:
> Lähetetty: 9. toukokuuta 2012 16:45
> Vastaanottaja: mapserver-users at lists.osgeo.org
> Aihe: Re: [mapserver-users] multiple transparent colours
> 
> Frank,
> 
> Would it be possible to make mapserver pick up the NODATA 
> value from the 
> gdal source file. Maybe using a keyword like "OFFSITE AUTO". 
> This would 
> be especially useful when using a tileindex.
> 
> Any thoughts on this? Should I create a ticket for something 
> like this?
> 
> -Steve W
> 
> On 5/9/2012 9:36 AM, Rahkonen Jukka wrote:
> > Hi,
> > Perhaps you cannot literally set a colour as transparent in 
> a tiff but
> > for sure you can define a nodata value and then 
> applications can make
> > nodata pixels transparent. That is the most normal way to do it with
> > Mapserver and OFFSITE. I believe that Mapserver does not 
> even care if
> > tiff has a nodata tag set but you can give whatever value 
> for offsite in
> > a mapfile.
> > I have not played at all with alpha, but perhaps there is 
> some way to
> > give a list of pixel values which should be transparent and 
> convert them
> > all to a suitable alpha channel value.
> > -Jukka Rahkonen-
> >
> >     Fernando Nortewrote:
> >     Hi Christoph,
> >
> >     I try to understand, how did you set the specific color to
> >     transparent in a TIFF?
> >     For raster you can set the level of transparency/opacity to the
> >     image not to a color.
> >
> >     Att,
> >
> >     *Fernando Norte*
> >
> >     Desenvolvedor SIGWeb
> >
> >     tel.(31) 2533.9900
> >
> >     cel.(31) 9119.8814
> >
> >     skype: fernandoglobalgeo
> >
> >     	
> >
> >     Endereço: Alameda do Ingá, 88, 6º andar, Vale do Sereno
> >
> >     Nova Lima/MG - CEP: 34.000-000
> >
> >     www.globalgeo.com.br <http://www.globalgeo.com.br/>
> >
> >     "O presente documento pode conter material confidencial ou seu
> >     sigilo é protegido por lei.
> >     Quaisquer informações nele contida são destinadas exclusivamente
> >     ao(s) seu(s) destinatário(s)
> >     não devendo em nenhuma hipótese ser repassado a terceiros".
> >
> >
> >
> >
> >     2012/5/9 Christoph Schumacher
> >     <christoph.schumacher at pbs-schumacher.de
> >     <mailto:christoph.schumacher at pbs-schumacher.de>>
> >
> >         Hello everybody,
> >
> >         I have a problem setting up my wms.
> >         I have multiple tiff images that have different 
> colours to be
> >         set up as transparaent.
> >
> >         With the offsite parameter I can only set one 
> colour transparent.
> >
> >         Now my question is: Is there a way to make various colour
> >         transparent??
> >
> >
> >         best wishes and thank you very much
> >
> >         christoph
> >
> >
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> >
> >
> >
> >
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