mapping intermittent ponds

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mapping intermittent ponds

Postby hewhocaves » Nov 9, 2011 1:44 pm

So I'm putting together a cave map (literally, right now - illustrator is open in the other window) and I've got a question...

The cave has several mud-lined funnels which at certain times of the year are filled with water, but at other times of the year are empty. I suspect they're empty about a third of the year, with varying levels of water throughout the remainder.

The funnels are about 5' deep.

How do I represent them? As dry funnel shaped holes? As pools?

John
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Re: mapping intermittent ponds

Postby Martin Sluka » Nov 9, 2011 4:20 pm

Is there any problem to draw the passage two times parallel, one time dry, second filled with water and add there note about time of year in which is the variant valid. To add there animation which will change dependent on date isn't good idea I think ;o)
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Re: mapping intermittent ponds

Postby Chads93GT » Nov 9, 2011 4:27 pm

I would add an arrow and a notation. Caves change. I've long since given up trying to represent things that change with each flood.
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Re: mapping intermittent ponds

Postby BrianC » Nov 9, 2011 4:43 pm

hewhocaves wrote:So I'm putting together a cave map (literally, right now - illustrator is open in the other window) and I've got a question...

The cave has several mud-lined funnels which at certain times of the year are filled with water, but at other times of the year are empty. I suspect they're empty about a third of the year, with varying levels of water throughout the remainder.

The funnels are about 5' deep.

How do I represent them? As dry funnel shaped holes? As pools?

John


Dry funnel shaped holes that flood.
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Re: mapping intermittent ponds

Postby Scott Shaw » Nov 9, 2011 7:49 pm

Simple...Draw the cave as it is when you survey it, then note water levels can vary due to the weather.
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Re: mapping intermittent ponds

Postby hewhocaves » Nov 10, 2011 1:47 pm

Scott Shaw wrote:Simple...Draw the cave as it is when you survey it, then note water levels can vary due to the weather.


Oooh, excellent point. Not necessarily the note, though that is valuable too. Rather, the fact that the survey is a snapshot of the cave on the day it was surveyed. This is something that I knew, but hadn't fully internalized. Thanks!

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Re: mapping intermittent ponds

Postby George Dasher » Nov 12, 2011 10:46 am

I would be very tempted to flag that much change with a note--especially if it causes a safety issue.

As far as the actual cartographic symbol--I would draw the map at whatever water level you feel is most "normal."
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Re: mapping intermittent ponds

Postby Jeff Bartlett » Nov 15, 2011 4:01 pm

Chads93GT wrote:I would add an arrow and a notation. Caves change. I've long since given up trying to represent things that change with each flood.


I will quote Bob Osburn here: "Every survey is just a snapshot of the cave at that moment in time." Breakdown moves, silty passages choke shut and flood back open, artifacts and rigging are removed and replaced.

My advice is not to fall into the trap of trying to draw everything symbolically; even if you come up with a symbol that you think expresses the situation perfectly, and put it in the legend, it will manage to confuse people. Often times, just putting a text note in the vein of "pool levels vary widely with season" is the most direct, clear route. Since the pools contain water 2/3 of the time in your estimation, I'd draw them as containing water.
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Re: mapping intermittent ponds

Postby Extremeophile » Nov 15, 2011 6:29 pm

hewhocaves wrote:How do I represent them?
John

Depends on whether you're a pond half-full, or half-empty type of person.
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Re: mapping intermittent ponds

Postby Jeff Bartlett » Nov 15, 2011 10:25 pm

Derek wins!
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