It has been a while since I drafted my last cave map, but I have recently gotten back into surveying and mapping Florida air-filled caves. Frankly, I am surprised at what I perceive to be the current NSS surveying and mapping situation, with there being three sets of cave mapping symbols used in the USA. Hopefully, I am wrong about that perception and you nice people will set me straight.
Another surprise was to learn that the NSS website has some BOG vote documentation that there is an NSS-approved set of symbols, yet the NSS website neither cites a reference to it nor provides an internal or external link for it. Surely, this is an oversight, and if not, surely a selfless, experienced US cave surveyor is willing to write it up for the NSS webmaster to post?
I am looking at the MSS-NSS (no ready link) and UIS (
http://tinyurl.com/858vh83) cave symbols, and am trying to determine which would be better for my FL use. Obviously, if I intend my maps to be used outside the USA, UIS symbols are the obvious choice. OTOH, I doubt that few non-FL cavers would want to view my FL cave maps, and sadly, we use English measurements here, so the pragmatist in me will use feet rather than meters for FL cave maps.
I have looked at some of the differences among the three symbol sets for their applicability to FL’s usually small caves. Specifically, our caves are characterized by having small, often intermittent pools (calling them lakes is funny), lots of Recent and Pleistocene bones, lots of critters, only occasional stal, frequent phototrophic entrance stal (is there a better name for them?), occasional duck-unders (= sumps), little stream- or air-flow, frequent to numerous bedrock pillars, and abundant speleogens forming curtains and debris cones from overhead solution pipes that often define cave passage edges. Here are some of my observations from that assessment:
Phreatically-formed FL caves often have small pools of water that represent the top (water table) of the Floridan Aquifer. A lot of the pools have passages that a surveyor can clearly see extending underwater and leading out of sight. Because defining them accurately can be done only by diving, dashed-lines are an adequate temporary solution for representing them until cave divers can be coaxed into exploring them. Nonetheless, one can often see the underwater passages and they should be shown on cave maps, but current MSS, NSS, and UIS symbols make poor plan view depictions. Hatching is used in all three symbol sets for plan views, and drawing dashed passage lines within the hatching is confusing, making them look like incompletely erased mistakes. I think the MSS (p. 11) use of concentric dashed ‘sub-circles’ for pools is a valid start, but I will modify it for my use on plan views to only two concentric sub-circular solid lines as I have seen used on nautical charts. MSS wins a half-point.
The UIS symbol for cross-sectional views of pools sucks IMO. The rest of the world’s hydrological disciplines use a single horizontal line for the water table, as does the MSS / NSS (p. 14) symbol. However, the rest of the hydro-world adds a small hollow triangle pointing downward and touching the line, plus 3 short and ever-shorter horizontal lines below the triangle and water line (the net effect is similar to an electrical grounding symbol). With or without the triangle, underwater passages can be easily drawn. MSS and NSS win.
MSS has a bedrock pillar symbol that is the same as the UIS sump symbol – a potential conflict. However, the use of a standard geological bricked symbol (long horizontal lines connected by offset, short vertical lines) works very well. In fact, MSS uses this symbol for cross-sections showing lithologic control, and it makes sense to use that same symbol for plan views and cross-section views. The NSS symbol for a bedrock pillar (two directional hatching) is just too hard to draw small (not scalable). I see no UIS symbol for bedrock pillars, so perhaps my link to their system is an abbreviated version? Or perhaps the UIS method is to draw a hollow outline of the pillar? MSS wins half and standard geology wins half.
The MSS and NSS (and British) symbol for an underlying passage works for me, but the UIS symbol depicted on the NSS Survey & Cartography Section’s webpage (
http://tinyurl.com/7bcw8es) does not show the two passages touching, as they do not in reality. I presume that the S&C Section’s webpage version differs from the 1999 version due to more-recently voted updating? UIS wins.
I confess that I do not understand why MSS has differing symbols for underlying (p. 1) and overlying (p. 2) passages. Are they not just different points of view? What am I missing? Buford loses.
I prefer to leave off the UIS’s tiny arrow pointing in the direction of a cross-section’s viewpoint. MSS depicts it both ways. As Aristotle said, “Anything that does not add, detracts.” MSS/NSS wins.
FL cave pit entrances are usually vertical solution pipes of relatively uniform diameter that open into a phreatic room having a nearly horizontal ceiling, justifying a UIS dripline symbol. This works well with the UIS ‘pit open to the surface’ symbol. The MSS sinkhole symbol might confuse a reader because it could indicate either a depression within the cave, a sinkhole overlying the cave, or a pit entrance. In combination with the MSS ‘change in ceiling height’ symbol, however, it would look like a sinkhole within a hilltop. The NSS pattern, which is tick marks all the way through the line, overlaps with the ‘change in ceiling height’ symbol when the pit entrance and ceiling change are close to each other, as they typically are in FL. I could eliminate the ceiling height change in some cases, but on the cave map that I am currently drafting the subcircular pit transitions into a pit attached to a fault (tadpole-shaped), and the widened fault extends well above the flat ceiling. Thus, the UIS version’s solid subcircular line indicates for me an entrance rather than a contour, leaving real contours to be depicted by the other lines. UIS wins.
Incidentally, the concept of the indeterminate cave wall as depicted by all three symbol sets is a thing of the past for me, as I use a Stanley Fat Max distance laser that is alleged to be accurate to a tenth of an inch. It is really nice to be able to determine radial wall distances from the center of a room without having to lug the dumb end of a tape over there. It also makes solo surveying easy. Buford wins.
Any and all comments welcome, especially if you spot errors in my logic or have experience drawing the issues that perplex me. Everyone wins.