There are a few bits of information to keep in mind when trying to interpret the tables in these pages.
AbbreviationsNewsletters and MagazinesIUIsland UndergroundVNVICEG NewsJSMJournal of Subterranean MetaphysicsCCCanadian CaverCC-CECCanadian Caver Special Issue - Cave Exploration in Canada (1976)BCCBC CaverBooksUGMUnder Grotto Mountain. Chas Yonge 2001CCRCaves of the Canadian Rockies and Columbia Mountains. Rollins 2004Survey Information It’s important to remember that many of the longer cave surveys are works in progress, and the current length and/or depth will change in time. The lengths or depths for caves in progress are reported from a person holding the survey data. Survey Accuracy Cave surveying is conducted using some device to measure distances between survey stations, some way to measure direction (either relative or absolute), and, ideally, some way to measure difference in elevation. How this is done covers a spectrum of accuracy, from crude and quick to laborious and (hopefully) accurate. Most cave surveys in Canada use a fibreglass tape measured to the nearest centimetre, a Suunto sighting compass for bearings, and a Suunto clinometer for angles between stations. Usually, the passage dimensions are estimated and a sketch created in a notebook onsite. Here’s a general grading system for cave surveys, from the International Union of Speleology Have a look at the source link for more information.
Lengths and Depths?Cave depths are the vertical distance between the very highest part of a cave system to the very lowest point. Often the highest point will be the edge of the entrance sinkhole,though, this varies considerably depending on the “keenness” of the survey crew. Even the lowest point can change somewhat, since if it is a sump (point that is waterfilled) this could vary with season or be completely bypassed by cave divers. Cave lengths very often depend on a both a combination of the actual extent of the cave and the enthusiasm of the mappers. Surveyors mapping for the main passages and just sketching minor side-passages will end up with a published cave length far less than the meticulous crew who drag a tape into every nook and cranny.