How do I measure density of random point with a fixed area in MATLAB?
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Chun Yin Lui
am 20 Jan. 2021
Kommentiert: Adam Danz
am 21 Dez. 2021
There had a 9x9 area and I have generate a lot of point with this area in random.
How do I measure density of the red point (e.g. Bottom left).
Somebody can give something sample code to let me study with this topic? It is very helpful to my project research.
3 Kommentare
Mathieu NOE
am 21 Jan. 2021
hello
these are plot format option * = star, g = green, o = circle , r = red
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Adam Danz
am 20 Jan. 2021
Bearbeitet: Adam Danz
am 20 Jan. 2021
Use histogram2() or histcounts2() to compute 2D density.
Demo:
xy = randi(400,50,2);
subplot(1,2,1)
plot(xy(:,1), xy(:,2), 'r.')
axis equal
grid on
xlim([1,400])
ylim([1,400])
title('raw data')
binEdges = linspace(1,400,4);
set(gca,'XTick',binEdges, 'YTick',binEdges)
% Compute density in 3X3 bins
subplot(1,2,2)
h = histogram2(xy(:,1), xy(:,2), binEdges,binEdges,...
'DisplayStyle','tile','ShowEmptyBins','on');
axis equal
grid on
xlim([1,400])
ylim([1,400])
title('Density')
set(gca,'XTick',0:100:400, 'YTick',0:100:400)
cb = colorbar();
ylabel(cb,'Density')
% To label counts
[xTxt, yTxt] = ndgrid(h.XBinEdges(2:end)-h.BinWidth(1)/2, ...
h.YBinEdges(2:end)-h.BinWidth(2)/2);
labels = compose('%.0f', h.Values);
hold on
text(xTxt(:), yTxt(:), labels(:), 'VerticalAlignment', 'Middle', 'HorizontalAlignment','Center')
12 Kommentare
ytu1990
am 21 Dez. 2021
After calculating the density, how to return the density value to be linked to the coordinate of original point?
For example, return the value "9" to the points in the (1,1) grid...
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