[MS4W-Users] WMS imagery has transparent pixels

[Smith, Michael]

We have deployed MapServer (MS4W) as a WMS server for the State of
Maine, it has been running great for 18 months and holds all of our
imagery data now.  Some recent additions show an oddity which I chalk up
to our still-growing understanding of MS.

A few of our imagery WMS have 'holes' in them wherever the pixel values
are 255 255 255.  These can be from either JP2 or TIF rendering.  In
typical GIS software these pixels show as white.  But when rendered
through WMS they are transparent.

I have tried several variations using AGG/PNG vs. GD/PNG, RGB vs. RGBA,
IMAGECOLOR, and TRANSPARENT=OFF (with RGBA).  Still no luck.  My current
mapfile is below.  You can see this in my publicly-facing service (URL
is in the WEB section below).

Any suggestions?

**********
Michael Smith
State GIS Manager
Maine Office of GIS
State House Station 174
264 Civic Center Drive
Augusta ME 04333-0174
(207) 215-5530


MAP

CONFIG "PROJ_LIB" "C:\ms4w\proj\nad"

EXTENT -72 42 -66 48
UNITS DD
SHAPEPATH "d:/mapserver_data"
RESOLUTION 96
MAXSIZE 8192

OUTPUTFORMAT
  NAME "AGGPNG24"
  DRIVER "AGG/PNG"
  MIMETYPE "image/png"
  EXTENSION PNG
  IMAGEMODE RGB
  FORMATOPTION "INTERLACE=OFF"
END

IMAGECOLOR 0 0 0
IMAGETYPE AGGPNG24

WEB
  METADATA
    "wms_extent" "-72 42 -66 48"
    "wms_server_version" "1.1.1"
    "wms_title" "Maine_orthos"
    "wms_onlineresource"
"http://mapservertest.maine.gov/wms/mapserv.exe?map=c:/wms/orthos.map&SE
RVICE=WMS&"
    "wms_srs" "EPSG:4326 EPSG:26919 EPSG:26983 EPSG:26984"
    "wms_abstract" "State of Maine aerial orthophotos provided by the
State of Maine, Maine Office of GIS and Maine GeoLibrary Board"
  END
END

PROJECTION
  "init=epsg:4326"
END

LAYER
  NAME "Baxter_04"
  GROUP "Baxter_2004"
  MAXSCALEDENOM 10000
  METADATA
    "wms_title" "Baxter_.6m_2004"
    "wms_srs" "epsg:26919"
  END
  TILEINDEX "baxter_04\index.shp"
  TILEITEM "LOCATION"
  TYPE RASTER
  OFFSITE 0 0 0
  PROJECTION
    "init=epsg:26919"
  END
END

LAYER
  NAME "Baxter_04_5m"
  GROUP "Baxter_2004"
  MINSCALEDENOM 10000
  MAXSCALEDENOM 100000
  METADATA
    "wms_title" "Baxter_5m_2004"
    "wms_srs" "epsg:26919"
  END
  TILEINDEX "baxter_04\index5.shp"
  TILEITEM "LOCATION5m"
  TYPE RASTER
  OFFSITE 0 0 0
  PROJECTION
    "init=epsg:26919"
  END
END

LAYER
  NAME "Baxter_04_25m"
  GROUP "Baxter_2004"
  MINSCALEDENOM 100000
  METADATA
    "wms_title" "Baxter_25m_2004"
    "wms_srs" "epsg:26919"
  END
  TYPE RASTER
  DATA "baxter_04\mosaic25_1.tif"
  OFFSITE 0 0 0
  PROJECTION
    "init=epsg:26919"
  END
END

END