contour map and pdf for a 2d dataset

I have a set of data that includes x and y coordinates. The outline of these points create a concave polygon, similar to a figure 8. I would like to get the probability density function for this (I've been using ksdensity) and contour it so that the contours stop at the outer edge of the data.

So far, manipulating ksdensity (specifically, the bin size/width) has resulted in contours that either excludes data, or includes areas without any data points.

Any ideas?