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Density Plot coloring issue

• To: mathgroup at smc.vnet.net
• Subject: [mg79715] Density Plot coloring issue
• From: Yvon <ymgrigsb at yahoo.com>
• Date: Thu, 2 Aug 2007 03:56:32 -0400 (EDT)

I'm having an issue where my density plot will color all the cells
EXCEPT the minimum above 0 and maximum values in my list.  It seems to
occur irregardless of whether I use the custom function I wrote or
ColorFunction -> (Hue[2/5, 2/3, 1.2 - #] &)

This is driving me crazy, please tell me what I'm doing wrong.  For
the dataset given below, all the cells are colored except cell 3,4
(value=3.93) and cell 6,1(value=7.41)  They are white, along with the
0.0 values which is the first value in my color table.

However, if I duplicate the min value  by changing another value
within the list (for example, replace (cell1,1) 6.75 with 3.93), then
the color for both 3.93 cells change to what is expected.  If I
replace 6.75 with 7.41, both 7.41 cells are white, if I replace 6.75
with 7.42, then cell 1,1 is white and the cell 6,1 changes to what is
expected.  Can someone tell me what is going on here?!!

cList = {{6.75, 5.85, 0., 6.39, 7.41, 0.}, {6.4, 5.57, 0., 6.6, 6.68,
   0.}, {5.99, 5.51, 0., 6.24, 6.37, 0.}, {6.1, 5.72, 3.93, 5.92,
   5.89, 0.}, {5.71, 5.85, 6.05, 5.92, 6.06, 0.}, {5.62, 5.64, 5.61,
   5.42, 5.14, 0.}, {0, 0, 0, 0, 0, 0}}

numColors = 10
minLWC = 0
maxLWC = 10

CellColor[index_] := Module[{cTable, s},
  (*White,purple,blue, light blue, light green, kahki, light yellow,
  light orange, pink, red *)
  cTable = {{1, 1, 1}, {0.5, 0, 0.5}, {0.4, .6,
     0.9}, {0.7, .9, .96}, {.8, 1, .7}, {.6, 0.8, .2}, {1, 1,
     0.5}, {1, .84, 0}, {1, .75, .8}, {.86, .08, .24}};
  s = Partition[Map[RGBColor, cTable], 1];
  RGBColor[cTable[[index]]]
  ]

GetColor[x_] := (p =
   Round[Abs[(x - minLWC)*numColors/(maxLWC - minLWC)]] ;
  CellColor[p])

ListDensityPlot[cList,  InterpolationOrder -> 0,
 ColorFunction -> GetColor, ColorFunctionScaling -> {\!\(\*
ButtonBox["False",
BaseStyle->"Link",
ButtonData->"paclet:ref/True"]\)},
 Mesh -> {numCols - 1, numRows - 1}, PlotRangePadding -> None,
 DataRange -> {{0, numCols}, {0, numRows}},
 Epilog -> {Hue[0, 1, 1],
   MapIndexed[Text[#1, #2 - .5] &, Transpose[cList], {2}]}]

Your help is greatly appreciated!!

Yvon

• Follow-Ups:
  • Re: Density Plot coloring issue
    • From: Brett Champion <brettc@wolfram.com>