Q:

White spots in ListDensityPlot

I have a problem with ListDensityPlot.
I have some data on an irregular grid.
I try to plot them with 
xStart=0;
xEnd=1000;
yStart=170;
yEnd=270;
ListDensityPlot[data,PlotRange -> {{xStart, xEnd}, {yStart, yEnd}}, FrameTicks -> True, 
AspectRatio -> Abs[(yEnd - yStart)/(xEnd - xStart)], PlotRangePadding -> None,   
ColorFunction -> (If[#1 === 0 , Black, GrayLevel[Rescale[#1, {0, 1}]]] &), 
ColorFunctionScaling -> False, LightingAngle -> None, InterpolationOrder -> 0, ImageSize -> 1000]

In the output I have some ugly white spots:

If I change my plot (setting xEnd = 230), the white spots disappear:

So, from my point of view, the white spots are not caused by my data. Somehow Mathematica (I am using 9.0.1) causes them.
To solve this problem I am using the following workaround:
ListPlot3D[data, PlotRange -> {{xStart, xEnd/1}, {yStart, yEnd}, All}, 
BoxRatios -> {1, Abs[(yEnd - yStart)/(xEnd - xStart)], 1}, 
ColorFunction -> (If[#1 === 0 , Black, GrayLevel[Rescale[#3, {0, 1}]]] &), 
ColorFunctionScaling -> True,Mesh -> None, ImageSize -> 1500, 
ViewPoint -> {0, 0, Infinity}, InterpolationOrder -> 0, BoundaryStyle -> None]

This gives me a nice output:

What can I do that I get the same output with ListDensityPlot? At least I need ListDensityPlot because changes in the InterpolationOrder look there different than in the ListPlot3D.
There is perhaps a similar question here, but rescaling does not help here. Additionally, my problem is “solved” with ListPlot3D, Eli Lansey’s problem not.
I would be happy about some help!

A:

The white generally indicates plot range clipping.  See ListDensityPlot, the ClippingStyle and PlotRange sections.
Setting
PlotRange -> {{xStart, xEnd}, {yStart, yEnd}, All}

will include all data values.  If the data has a few extreme values, including the whole range will flatten out smaller variations in the data.

