Contour plot of the number of historical 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.) Note that all tracks that pass the filter used to create the synthetic events, and the best track filters specified in params.m , are used.

This routine uses the free m_map utilities which are included with the scripts. Some of the properties of the map can be set in the params.m file.