Drawing cross-sections

[CaveBuddy95]

Hi there, me and Alan are progressing quite well in our re-survey of the cave system of Tajma Ha in Mexico and we are now at a point where details are getting in the way.
It is a very interesting learning curve, as we try to figure out most of the headaches ourselves. Of course, I can't forget to say how helpful CDfs members have been so far in helping us out.

So here is the tricky part, at least for me!
Le's assume we are aiming at a grade 4 map for a final result... I know, it is a lot of work and it may not end as we plan, but hey, dream is on!
For the map to be super interesting to viewers, it really need some cross-sections. And some sh$&t hot ones!
I've been in the cave we are surveying, or re-surveying for that matter, with a slate w/grid and a sharpened eagle eye, for measuring.
(note to reader: survey is done with tape measure + sonar, suunto compass +or-2° and uwatec+vytec for depth references)

And each time I am in front of a potential interesting cross-section, I feel like Picasso on a bad day....GRRrrrrrr..... so frustrating.
So I was in search of some input/advices for the 'how to cross-section' guide. Cross-section for dummies is not out yet.. Needless to say that we are looking for sh&@t hot cross-sections!

Any help is help.
Thank you very much

Saludos,

[mpoucher]

I've found its a matter of practice. Get some basic measurements of the passage and then draw the profile around it. In my opinion, the visual interpretation of how the cave looks is more important than absolute accuracy, so to make them "sh&@t hot " I have to draw them several times and experiment with shading, line widths, and stipling to make it look right ( I do mine by hand with pen and pencil, computer drawing just don't look right to me). My advice is look at some other maps and then experiment and practice until you find a style you like.

[CaveBuddy95]

thanks Mike
would you consider using photography to have the section 'workable' on the outside?
Once you have the measurements of the section, try to put things back on paper I guess.

cheers

[Webmaster]

It doesn't need to be exact either, think about what would be useful to you if you were looking at the finished map. Don't get bogged down in trying to reproduce every little bump. Look back and forth from the passage to the x-section, draw a little, look, draw a little.... There may be interesting areas where you spend more time, but you're really just trying to give an idea of the 3D nature of the passage.

We had a joke,
"What's the passage like?"
"It's 15' tall and 25' wide."
"Awesome, borehole!"

"With a cross section shaped like a + sign."
":-("

That's something important that you'd hope to get from the map, something that the LRUD measurements aren't necessarily going to tell you, and that might not be clear from the plan view.

Once you get the sketch, you can worry about all the "prettying up" when producing the final map.

[CaveBuddy95]

its my fault, I do have a nasty habit of complicating things up!
thanks guys, I will apply a dose of patience and your advice for my next run. A this end, its a squetch so no big deal.

Just have to get my MR11 charger fixed or replaced so I CAN PROCEED........

Thanks again

[L.A.]

survey is done with tape measure + sonar, suunto compass +or-2° and uwatec+vytec for depth references)

Which sonar device are you using?

[mdax]

Definitely would like to know also. Has anyone successfully modified fishing sonars for cave data or no?

[CaveBuddy95]

We are using the Vexilar Inc. Hand Held Sonar. It helps a lot in clear passages (no obstacles) and gin clear water. Very useful in huge rooms!


Check it out here