load('speed_load.mat');
x = i_Engine_Speed;
y = i_Instantaneous_Percent_Load;
xbins = 600:100:2200;
ybins = 0:10:100;
xi = interp1(xbins, 1:numel(xbins), x, 'nearest', numel(xbins));
yi = interp1(ybins, 1:numel(ybins), y, 'nearest', numel(ybins));
H = accumarray([yi(:), xi(:)], 1, [numel(ybins), numel(xbins)]);
hf = figure;
ha = axes;
ylabel('Instantaneous Load [%]')
xlabel('Engine Speed [RPM]');
axis([xbins(1), xbins(end), ybins(1), ybins(end)]);
hold(ha, 'all');
hi = imagesc(xbins, ybins, H);
[Xbins, Ybins] = meshgrid(xbins, ybins);
ind = H(:) > 0;
scatter(Xbins(ind), Ybins(ind), H(ind).^1.1, [0, 0, 1])