[mapserver-users] Using MASK to obscure areas

[Fabian Schindler]

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Dear mapserver devs and users,

Using the MASK feature of mapserver I'm able to define areas which are
visible (masked 'in'). My goal is to achieve the opposite, to mask
*out* areas of the image which shall be rendered transparent.

Is there any way to do this?

Thanks,
Fabian


P.S: My mapfile currently looks like this (it is autogenerated, as I'm
using mapscript for the task):

MAP

  # ... a lot of stuff left out for brevity

  PROJECTION
    "init=epsg:4326"
  END # PROJECTION

  WEB
    METADATA
      "ows_enable_request"	"*"
    END # METADATA
  END # WEB

  LAYER
    NAME "masklayer"
    CONNECTION "mask.json"
    CONNECTIONTYPE OGR
    METADATA
      "wms_srs"	"EPSG:4326"
      "wms_include_items"	"all"
      "ows_srs"	"EPSG:4326"
      "gml_include_items"	"all"
    END # METADATA
    PROJECTION
      "init=epsg:4326"
    END # PROJECTION
    STATUS ON
    TYPE POLYGON
    CLASS
      STYLE
        COLOR 0 0 0
      END # STYLE
    END # CLASS
  END # LAYER

  LAYER
    NAME "data"
    DATA "data.tif"
    EXTENT 11.331755 32.19025 28.29481 46.268645
    MASK "masklayer"
    METADATA
      "wms_srs"	"EPSG:4326"
      "wms_extent"	"11.331755 32.190250 28.294810 46.268645"
      "ows_srs"	"EPSG:4326"
    END # METADATA
    OFFSITE 0 0 0
    PROJECTION
      "proj=longlat"
      "datum=WGS84"
      "no_defs"
    END # PROJECTION
    STATUS OFF
    TYPE RASTER
  END # LAYER

END # MAP
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