This repo exists to provide sample data demonstrating a potentially confusing aspect of Mapserver tile index. See Unexpected result from overlapping images in tile index for the discussion.

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I want to render the following images using this tile index (geojson) via the mapfile.map with a layer:

LAYER
        NAME my_layer
        TYPE RASTER
        TILEINDEX tindex.shp
        TILEITEM "location"
        OFFSITE 0 0 0
        STATUS OFF
    END
END

1. black.tif with pixels having the value 1

2. gray.tif with pixels having the value 128

I expect the output of this WMS request to look like this:

However, I actually get the output of gray.tif via the WMS request:

http://localhost:8080/?SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&FORMAT=image%2Fpng&TRANSPARENT=true&LAYERS=my_layer&WIDTH=256&HEIGHT=256&SRS=EPSG%3A4326&STYLES=&BBOX=-89.2968750,40.6933594,-89.2089844,40.7812500

Should Mapserver be able to handle this? I have a couple of work-arounds that I'm not crazy about:

1. Add Layer masks to two separate layers, make two WMS requests and stack the results client side. This works for two layers. However, I actually have many images which I need to stack.
2. I could burn in NODATA values (or use a mask) to gray.tif, but I'd rather not modify my source data.