trogman wrote:That's just it-they are surveyed. If you establish a station and measure an LRUD at that station, is that not part of your survey?
I think so. Survey stations are reference points, not the beginning and end of the survey.
Extremeophile wrote:Most people I know often estimate LRUDs, and often they report up and down directly from the station rather than the maximum passage dimensions, so those elevations almost never have the same accuracy as a survey station.
I was wondering about this when surveying in Maxwelton. If you record dimensions strictly from station, the sketcher then needs to take multiple measurements at the station and sketch the cross section to scale in to have an accurately sized section, and accurate ceiling heights. If you record the maximum dimensions at the station though, you can draw the section not to scale, and the cartographer can still create an accurate cross section. What to do?
In order to deal with this on many of my own surveys, I record the maximum dimension at each station. In short stream caves and others with little or no gradient, I record no inclination data, and put no stated depth on the map. This allows me to record only three passage dimensions: left, right, and total height.
Short stream caves actually help to illustrate the vagueries of cave depth. Suppose I put every station on the floor. The surveyed depth, if based on the stations, could be 1' or 2' or 0'. But what if the cave has a big entrance with a ledge on one side? If I climb up on the ledge and put the first station near the ceiling, all of a sudden the cave is 24' deep. I intended, with my original question, to find out what the accepted method was. The answer seems to be "whatever you want". That's ok with me.