Sketching from memory instead of surveying.

[AndrewA]

How would you know that without having been to the cave

One way is to publish the original data, including the sketches. With modern paperless surveying this even shows what internal features where measured to. It has lots of other advantages as well, but the main one being that we will not have to survey a cave again because we do not know where the data is. This system also records changes, so the whole history is there.

Still embrionic, but worth a look

http://cave-registry.org.uk

Andrew