Survey Data and technique

[CaveBuddy95]

Hi all,
I am taking some notes (bearings and time into dive) during my dives so I can have references for future dives in the same cave but I am wondering what kind of datas are more useful to start drawing maps or maybe stick maps.

More precisely what do you put on your survey slate?

Thanks for your help.


Saludos,

[phillip1]

Depth, azymuth, distance and station numbers + a space for additional info on each station line for leads, formations etc.. on the slate for a basic stick map.
If you take bearings and distance (if line is knotted) at each station you can make a relatively good stick map very fast.

[CaveBuddy95]

Thanks Phillip.
I guess you count the stations on your way in and then start from the last one as you turn the dive??
Thats a lot of info on a slate!! Any tips on how to keep things clear?
Maybe a pic of a survey slate would be great!!
Thanks again for your help

Saludos,

[apitkin]

Have a look at Mike Poucher's website:

http://www.cavesurvey.com/

[CaveBuddy95]

Hi there,
I did thanks, particularly like the "math" section!
Also on Hans's blog I found some stuff, all good.

Anyone wants to share his/her surveying experience? Don't reveal all your secret but maybe some funny stories related to filling up the survey slate.

Thanks again

Saludos,

[rchrds]

Thanks Phillip.
I guess you count the stations on your way in and then start from the last one as you turn the dive??
Thats a lot of info on a slate!! Any tips on how to keep things clear?
Maybe a pic of a survey slate would be great!!
Thanks again for your help

Saludos,

CB95- take a look at the picture below- get some of this plastic "paper" and use it for cave survey, or make something similar yourself on a slate- the offset azimuth and distance between the stations is much more clear than other formats and eliminates questions of from/to confusion. This format (standard in dry caving, BTW) allows you to easily get all of the information in there that you need for underwater survey.Most people do not use the LRUD (Left, Right, Up, Down) data on the first dive, as it can be quite time consuming to collect accurately. It IS important that you note any discriminating points at each station, as it will allow you to re-find the stations on subsequent dives, particularly if you cannot use depth to discriminate.

As for numbering stations, I would be careful about making a habit of laying line in, and surveying out. Surveying often takes more time, and can create issues with gas management. Much safer to plan on surveying on your second dive, so that you may survey going in. If conditions do not permit this, however, just start with whatever station number you want (or is appropriate) at the end of the line, and count down on your way out of the cave. When you get out, you can renumber your station numbers on your slate so that they match the last station on the previous stretch, or 1 or zero, depending on how your like to begin your surveys. (For example: Say I lay 840 feet of line on the way in. I have loads of gas, and the landowner will only let me do one dive, so decide to survey out. My EOL station I number as 50, and start counting down on my way out. Hopefully, I'm in the 20s when I reach the entrance. Once I get my gear off, I renumber my stations- Station Zero is the station at which I take a GPS location, always at the water surface or above, and may or may not be in the cave. Station 1 is the entrance of the cave, or what would be the dripline if the cave were dry. This is usually at the beginning of my guideline in open water. Then I renumber the rest of the stations, leaving my end of the line station at #34. Don't try to to higher math underwater- you'll just screw it up.

Once you have your data crunched- you can replot your data on the backside of the page (picture 2) and then on your next dive, draw in the walls, floor and wall details and whatever else as necessary. This is where being able to identify your previous stations becomes so important.

If you have more questions, drop me a line (rchrds.caver@gmail.com) or come on up to the CDS convention and take either Mike Poucher's survey class (more appropriate to your level) or mine, and learn how to make finished digital maps!

Jason Richards

[phillip1]

If the line is knotted at regular intervals, just count knots between stations, then get a bearing and depth on each station and continue on like that, if for example there is less distance between two knots before getting to a station or after you can measure your forearm and use that to measure the missing piece and add the distance to the counted knots (usually 10ft apart).

You can swim to your planed turn around and then just start surveying out, for a complex cave or big cave you need to have station markers on each station and if there are more than one line each line needs a name and then a station number.
That way all the lines can be compiled together on one map, and each ine has it's own set of station markers.

If it's a single line simple cave that is walled out you can simply swim to the end of the line and then survey out, however you still would be better of with fixed numbers station markers so as not to get confused as to what station is what on future surveys.

I am no expert on making maps but it is not as difficult to make relatively precise maps as one would think.

In Compass if you get a GPS lock on station 0 (outside) then you can place the cave on a Google map which is really cool to see were it is going and maybe connect to other caves etc..

[DeepSea]

Jason...I have one of your custom designed sheets from www.riteintherain.com on my desk now -- THANK YOU! I am actually planning on ordering more this week.

Jason's sheet is designated R-168. If you contact www.riteintherain.com / 253.922.5000 you can order them as well.

CB95- take a look at the picture below- get some of this plastic "paper" and use it for cave survey, or make something similar yourself on a slate- the offset azimuth and distance between the stations is much more clear than other formats and eliminates questions of from/to confusion. This format (standard in dry caving, BTW) allows you to easily get all of the information in there that you need for underwater survey

Jason Richards

[FW]

You can swim to your planed turn around and then just start surveying out ......

Be very careful here, if you swim to thirds and survey going out, you are using some of your reserve gas to survey. We have lost two famous survey divers doing that. If your planed turnaround is less than thirds, then you are probably OK.

[mpoucher]

For exploration, I always survey out unless conditions are too bad to see the slate. I've found that the second dive doesn't always happen. I usually turn just shy of thirds 200 psi or so, and usually I use less gas to survey - going slower, concentrating on a familiar task, etc. slows my breathing rate. Usually. I also pay attention to gas management.

I take depth, azimuth, distance, UDLR, and notes in that order. I try to get at least some sidewall for future reference and generally estimate distances to get then most data in the least time. I don't number stations, or use a pre-printed sheet. If there are no tees, numbers aren't needed unless you have labeled stations in the cave. If there are tees, I note them or use an asterisk or number to label the station where the tee starts.

I use wet-notes for my data and take the depth, azimuth, distance, UDLR on one line. Notes, profile or plan sketches and any other info is recorded underneath the surey data. Since it is blank paper, I can write whatever I need. Some sheets for non-descript passage may have 15-20 stations, detailed passage may 2-3 stations. I also llabel and date the begiining and end of each survey.

Mike Poucher