Rules of survey/maps

[RN]

I'm considering a survey project in an unmapped section of a popular cave. My question is if I wanted to produce a map of this area but don't want to survey the rest of the cave that's already been surveyed, what's the way this is usually done to still be able to show the area of the new mapped area in relation to the already surveyed cave. BTW, we're talking about several hundred feet of unsurveyed passage.

[rchrds]

Your best bet is to survey about 100 feet on either side of your section, so you have something of the original survey to relate it to (unless you know exactly where the stations were) then, when you go to draw it, show a reduced version of the original map with an expansion reference from the original map to your map. This is all relative to the sizes of the maps in question and the size of your finished product. If you are trying to cram 1000 feet of detailed map onto an 8.5x11 you're probably not going to have much luck, but if you're only doing sidewalls and line plot, you might be able to work it out. In either case, you will have to show scale references for BOTH maps, and they also should have the same north orientation, otherwise it gets a bit confusing. If you are just doing it for routefinding, that is probably enough. If you are trying to set it up for GIS and land plot it, you are going to need the original data, or you'll have to survey to a known entrance. Trying to set GIS plots up with old maps is pretty difficult, I've found that most dont tend to really match the printed scale and azimuth once you take declination, multiple copies and hand drafting into account. It is much easier if you have multiple entrances.

jason

P.S> as an example... If you wanted to make a map of some of the outlying areas of Jackson Blue, it might be enough to just show your map with a small section of the main line, and include one of the distance markers on your map indicated on the main line. They have become pretty permanent, and should work as a reference, and people would most likely be able to use the map that way.

[aainslie]

I'm considering a survey project in an unmapped section of a popular cave. My question is if I wanted to produce a map of this area but don't want to survey the rest of the cave that's already been surveyed, what's the way this is usually done to still be able to show the area of the new mapped area in relation to the already surveyed cave. BTW, we're talking about several hundred feet of unsurveyed passage.

So... at 10:01 you post asking when little river closes, then at 10:39, about how to survey new passage in an old cave....

Hmmmm... time to look for recently disturbed parts of Little River

:)

[Slüdge]

Dude, you need to set your time zone in "User CP."

[RN]

Jason, thanks for the response. That's what I was looking for. I've been thinking I could survey a couple hundred feet to either side of the access points for this area (I think there are access points, still exploring it), and then reference back to a current map of the system.



So... at 10:01 you post asking when little river closes, then at 10:39, about how to survey new passage in an old cave....

Hmmmm... time to look for recently disturbed parts of Little River

:)

LOL! Not LR, that I promise. I haven't been in LR in over a year now. Nice try though!

Oh, and look for disturbed parts whereever you want. The only thing disturbed was some silt/sediment on the ceiling, and that was disturbed by my bubbles.

[apitkin]

Jason, thanks for the response. That's what I was looking for. I've been thinking I could survey a couple hundred feet to either side of the access points for this area (I think there are access points, still exploring it), and then reference back to a current map of the system.


Even better, try to get hold of the original surveyor(s) and talk to them about it. They may be able to give you the old survey data, or alternatively incorporate your survey in a new version of their map.

Of course, you may be unable to speak to them for whatever reason. And they may have lost the original survey data, which does tend to lose value over time. It can be pretty hard to tie in new data to an old map without having the original survey data.

Andy

[aainslie]

Dude, you need to set your time zone in "User CP."

Huh - I wondered about that... thanks! Done now.

Good luck with the project! It seems to me that as long as you have the original map and know where your point of intersection is, you should be able to make an overlay, i.e. a new map with one co ordinate (the point of intersection) tieing it in with the old one.

Sounds like fun!

Andrew

[DeepSea]

You might also want to contact the CDS and NACD. They have MANY surveys and maps in their archives.