How big is a cave?

From the original idea of ranking caves according the traditional method by length and deep we have arrived to the idea of having a single number including human objective and subjective cave evaluation. To arrive to this idea we had to reconsider our usual attitude to see a survey as a succession of numbers in the metrical space to a more complex but more satisfactory way to see the cave inside the mountains where it is generated and its physiological complexity related to the explorers. The data needed to build this rank are mainly what we are used to collect from a cave including data that could be easily collected using portable physiological devices. The introduction of a fractal dimension is considered as the needed mathematical effort in order to achieve the result of combining the cave importance related to the mountain surrounding it. In this work I tried to simplify at maximum the use of the needed math and all difficulties have been supported with notes and explanations. This method has been confronted with existing analogues works in order to evaluate the goodness of the model.