hotspot resize the map depending of the number of active/published elements inside the category, centering the markers.
If you go to the demo page
http://demo.compojoom.com/hotspots
click on the category: education. This one is covering almost the whole world.
but if you click on the category: park, the size of the map is reduced to eliminate all the unnecessary empty space centering all the published markers.
if you have an empty category, you will see the whole map. To avoid that just populate the category or don't publish it until you have something to put inside.