A customizable sized grid can now be drawn over the world map and the grid cells can be colored or contain a text item. Below I have plotted a grid of 30x30 cells. The number inside each is the number of stations in that grid cell. The stations are also plotted as blue dots. The image is quite blurry due to the jpeg compression.
In the image below a grid of 10x10 cells is drawn with cells containing more than 10 stations highlighted.
Finally 30x30 cells again with the proportion of area of the globe each cell contains: