I am considering creating some sort of model of the Earth using real world collected data. Things like worldwide height maps certainly exist, as do many maps of minerals, rainfall, etc.
Are there worldwide data available on underground cave systems?
By density, I mean the likelihood of there being a cave in a certain place, given coordinates. Hence it does not have to be exact (although this would be better), but a mathematical model or approximation would be useful if the former does not exist.