SCATTERCLOUD creates a scatterplot from X and Y data sets, and overlays it on top of a density plot of the same data.
From the help:
SCATTERCLOUD display density of scatter data
SCATTERCLOUD(X,Y) creates a scatterplot of X and Y, displayed over a surface representing the smoothed density of the points. The density is determined with a 2D histogram, using 25 equally spaced bins in both directions.
SCATTERCLOUD(X,Y,N) uses N equally spaced bins.
SCATTERCLOUD(X,Y,N,L) uses L as a parameter to the smoothing algorithm. Defaults to 1. Larger values of L lead to a smoother density, but a worse fit to the original data.
SCATTERCLOUD(X,Y,N,L,CLM) uses CLM as the color/linestyle/marker for the scatter plot. Defaults to 'k+'.
SCATTERCLOUD(X,Y,N,L,CLM,CMAP) uses CMAP as the figure's colormap. The default is 'flipud(gray(256))'.
H = SCATTERCLOUD(...) returns the handles for the surface and line objects created.
Eilers, Paul H. C. & Goeman, Jelle J. (2004). Enhancing scatterplots with smoothed densities. Bioinformatics 20(5), 623-628.