[Mapserver-users] I have some landsat 7 data that I want to t ile : overlap + transparency

[Kralidis,Tom [Burlington]]

Hi Stephen,

What are your requirements for using the Landsat 7 Orthoimagery in
MapServer?

The CCRS WMS has the entire Landsat 7 Orthorectified Imagery collection,
which is on GeoGratis, available as OGC:WMS:

URL: http://ceoware2.ccrs.nrcan.gc.ca/cubewerx/cubeserv/cubeserv.cgi
Layer name: L7O_B743:CEOWARE2

Note that this layer is also timestamped, i.e. you can query via TIME in
OGC:WMS also.  The scenes' black areas are transparent.

Just thought it'd be easier to point to an OGC:WMS of this data rather than
roll your own.

Another comment: I'd be interested, as a separate exercise, how MapServer
deals with overlapping images in a given layer.  What kind of algorithm is
done between scenes which overlap?

Thanks

..Tom

=========================
Tom Kralidis
Systems Scientist
Environment Canada
Tel: +01-905-336-4409
http://www.ec.gc.ca/cise/

========================= 

> -----Original Message-----
> From: Stephen Clark [mailto:stephen.clark at focus.ca] 
> Sent: Friday, January 30, 2004 6:52 PM
> To: Frank Warmerdam
> Cc: mapserver-users at lists.gis.umn.edu
> Subject: Re: [Mapserver-users] I have some landsat 7 data 
> that I want to tile : overlap + transparency
> 
> 
> Frank,
> 
> My landsat data is from the Geogratis web site :
> 
> http://geogratis.cgdi.gc.ca/download/landsat_7/ortho/geotiff/utm/
> 
> Specifically these three scenes as example:
> 
> http://geogratis.cgdi.gc.ca/download/landsat_7/ortho/geotiff/u
> tm/047021/
> http://geogratis.cgdi.gc.ca/download/landsat_7/ortho/geotiff/u
> tm/048021/
> http://geogratis.cgdi.gc.ca/download/landsat_7/ortho/geotiff/u
> tm/049021/
> 
> I compressed the files to ECW and produced this layer:
> 
> LAYER
>   NAME landsat_048_021_rgb
>   DATA 
> "d:/datasets/imagery/landsat/ecw/048021_0100_990804_l7_743_utm10.ecw"
>   TYPE RASTER
>   STATUS ON
>   TRANSPARENCY 60
> 
>   # turn off the black background in the image files
>    OFFSITE 0 0 0
> END
> 
> 
> >Do all the images have the same background value?   YES -- they do.
> There is a residual amount of black fuzziness around the 
> scenes after using the above OFFSITE command.
> 
> Here is a LAYER file for the tiled index of Landsat scenes:
> 
> LAYER
>   NAME landsat_tile
>   TILEINDEX "d:/datasets/imagery/landsat/landsat_index.shp"
>   TILEITEM "location"
>   TYPE RASTER
>   STATUS ON
>   TRANSPARENCY 60
> 
>   # turn off the black background in the image files
>   OFFSITE 0 0 0
> 
>   METADATA
>     WMS_TITLE "Lansdat 7 Imagery "
>     WMS_ABSTRACT "N/A"
>     WMS_SRS "EPSG:26910"
>   END
> 
> END
> 
> But this tiled layer does not have any transparency.  How 
> would I fix this?
> 
> thanks
> Stephen
> 
> ----- Original Message ----- 
> From: "Frank Warmerdam" <warmerdam at pobox.com>
> To: "Stephen Clark" <stephen.clark at focus.ca>
> Cc: <mapserver-users at lists.gis.umn.edu>
> Sent: Friday, January 30, 2004 2:31 PM
> Subject: Re: [Mapserver-users] I have some landsat 7 data 
> that I want to tile : overlap + transparency
> 
> 
> > Stephen Clark wrote:
> > > Hi All,
> > >
> > >
> > > I have some landsat 7 data that I want to tile but the scenes 
> > > overlap.
> > >
> > > Can I use some sort of command that can be added to the 
> "gdaltindex" 
> > > command to add a transparency value to these scenes so that the 
> > > overlap areas can show through.
> >
> > Stephen,
> >
> > Do all the images have the same background value?  If so, use it as 
> > the offsite value for the whole layer and it will be used 
> with all the 
> > images. The other alternative is to store the tiles in a format for 
> > which GDAL recognises "nodata" values, but this isn't very 
> convenient 
> > to arrange. There is no way to include nodata values in the raster 
> > tile index.
> >
> > Best regards,
> > --
> > 
> ---------------------------------------+------------------------------
> > ---------------------------------------+----
> ----
> > I set the clouds in motion - turn up   | Frank Warmerdam,
> warmerdam at pobox.com
> > light and sound - activate the windows | http://pobox.com/~warmerdam
> > and watch the world go round - Rush    | Geospatial 
> Programmer for Rent
> >
> >
> >
> 
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