Mapserver - Kernel Density Layer - weight

Question

I have created a map file broadly as shown below. I then created 6 points as in the DATA_TABLE. The 3 on the left have val 100 and the three on the right have val 1.

When I view this layer it renders as follows. With both sides looking the same? Why is the val value not affecting the weight and hence the colour ramp.

Have I misinterpreted something?

I was expecting the higher valued items on the left to be "redder".

LAYER
  NAME feature_heatmap
  TYPE raster
  CONNECTIONTYPE kerneldensity
  CONNECTION "point_data"
  STATUS ON


  PROCESSING "RANGE_COLORSPACE=HSL"
  PROCESSING "KERNELDENSITY_RADIUS=50"
  PROCESSING "KERNELDENSITY_COMPUTE_BORDERS=ON"
  PROCESSING "KERNELDENSITY_NORMALIZATION=1"
  OFFSITE 0 0 0

    CLASS
          STYLE
            COLORRANGE  "#0000FFFF"  "#FF0000FF"
            DATARANGE 0 255
          END
    END

 END

 LAYER
      PROJECTION
        "init=epsg:4326"
        "init=epsg:3857"
        "init=epsg:27700"
      END # PROJECTION


      NAME "point_data"
      STATUS ON
      TYPE POINT
      CONNECTIONTYPE POSTGIS
      <OBFUSCATED CONNECTION DETAILS>
      DATA "wkb_geometry from (SELECT wkb_geometry, feature_id as id, val::INTEGER as VAL FROM DATA_TABLE)))  AS FOO USING UNIQUE id using srid=4326"
      CLASSITEM val
          CLASS
            STYLE
              SIZE [val]
            END 
          END 

 END

Answer 1

Time to raise my hand and admit that this was a data issue not a mapfile one. The mapfile above works fine. The data view I had behind it didn't and hence caused all values to be the same.

Answer 2

Have you tried RANGEITEM in STYLE of the CLASS. Let say your value field is "MyRunningAverage", then it could be

  PROCESSING "RANGE_COLORSPACE=HSL"
  PROCESSING "KERNELDENSITY_RADIUS=50"
  PROCESSING "KERNELDENSITY_COMPUTE_BORDERS=ON"
  PROCESSING "KERNELDENSITY_NORMALIZATION=1"
  OFFSITE 0 0 0    
  CLASS
     STYLE
          RANGEITEM "MyRunningAverage"
          COLORRANGE "#0000FFFF"  "#FF0000FF"
          DATARANGE 0 255
      END # STYLE
END