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

[Stephen Clark]

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/utm/047021/
http://geogratis.cgdi.gc.ca/download/landsat_7/ortho/geotiff/utm/048021/
http://geogratis.cgdi.gc.ca/download/landsat_7/ortho/geotiff/utm/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
>
>
>