Contour plot of the number of tracks per unit area in the whole event set. Units are number per year per one degree latitude square. Each track is counted only once in each lat-long box (whose resolution may be set in params.m ), unless the track leaves the box and later re-enters it, in which case it is counted twice. (By extension, it is counted n+1 times if it re-enters the box n times after its first encounter.)

This routine uses MATLAB's mapping toolbox. Some of the properties of the map can be set in the params.m file.