horizontal lines (seem to be zero) in heat map

[yueyinqiu]

Hello! I'm using OxyPlot to draw the spectrums of some sound files.

Actually they are just a kind of Heatmaps. So I tried:

Plot plot = new();
var heatmap = plot.Add.Heatmap(values);
plot.Add.ColorBar(heatmap);
plot.SavePng("test.png", 10000, 10000);

Of course I should also share the data here:

values.txt

You can load the data file like:

var lines = File.ReadAllLines("values.txt");
var length2 = lines[0].Split(',', StringSplitOptions.RemoveEmptyEntries).Length;

var values = new double[lines.Length, length2];
for(int i = 0; i < lines.Length; i++)
{
    var split = lines[i].Split(',', StringSplitOptions.RemoveEmptyEntries);
    for(int j = 0; j < split.Length; j++)
    {
        values[i, j] = double.Parse(split[j]);
    }
}

Then the previous program will generate a image like:

It seems 'ugly', but in general it's what a spectrum should be. However these horizontal lines are not expected:

I have also tried to manually modify the values (this change is included in the previous data file). But it doesn't work. (1 is the biggest value in the array. So there is expected to be a yellow line, but it's still blue.)

So... have I did something wrong? Thanks for help in advance.

[yueyinqiu]

It's a problem in my other steps... And... [511, 0] will be drawn to the bottom left corner (0, 0) rather than 0, 511

[VisualMelon]

You can specify the corners with the X0, X1, Y0, Y1, and HeatMapCoordinateDefinition properties

[yueyinqiu]

Yes. The problem did not happen during the drawing process but in the other steps. Thanks a lot!