Extended profiles

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Extended profiles

Postby GroundquestMSA » Jun 22, 2014 6:17 pm

It seems that many modern cartographers have abandoned the concept of the extended profile. Since it is now easy to generate a dimensionally accurate profile from any angle using mapping software, is there any place for the continued use of the extended profile? Does modern mapping software even facilitate the creation of an extended profile?

I personally like the fact that the extended profile shows the entire length of the passage in a 2D view. Personally, I can more easily visualize a 3D concept by combining two clear 2D images, than by puzzling over two or more confusing quasi-3D images. Clearly, the extended profile has serious limitations; showing the relationship between loops over various levels, and dealing with a large number of closely-grouped passages are impossible.

A small cave I just started surveying is one that I feel could be well described with an extended profile. The three main branches are seperated by enough distance that they can stay connected and be plotted in different directions without overlap. I have never drawn a complete profile of any cave over 150' long, but I'm liking the way this one is turning out. Will the inclusion of an extended profile be other archaic feature (to go with hand drawing and MSpaint lettering) that will make my map an embarrassment?
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Re: Extended profiles

Postby Martin Sluka » Jun 23, 2014 4:58 am

GroundquestMSA wrote:Since it is now easy to generate a dimensionally accurate profile from any angle using mapping software, is there any place for the continued use of the extended profile? Does modern mapping software even facilitate the creation of an extended profile?


If you use DistoX and PocketTopo software, no any problem to sketch extended profile in a cave. There is software tool, which is able to help you in a case of big rooms, etc. :)
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Re: Extended profiles

Postby caver.adam » Jun 24, 2014 8:32 am

In Louisville, new cartographers are taught to do profile view on their maps. I don't see it going away with hand drawn maps (or screen drawn either). Whenever you print in 2D the extended profile is important to understanding the cave. Of course, many people who use a map are only using it for directions and they don't care about profile.
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Re: Extended profiles

Postby GroundquestMSA » Jun 24, 2014 6:52 pm

caver.adam wrote:In Louisville, new cartographers are taught to do profile view on their maps. I don't see it going away with hand drawn maps (or screen drawn either). Whenever you print in 2D the extended profile is important to understanding the cave. Of course, many people who use a map are only using it for directions and they don't care about profile.


I've been looking at a lot of grotto newsletters, and the majority of profiles being published are computer generated views from various angles, not extended profiles (a purely 2D view, as if the cave has been pulled into a straight line). In the old days, it would have been impossible for a non-mathematician to create the profile maps that are now common. Still, as I've said, I like the extended profile, not only because it's easy to draw, but because it's easy to mentally "walk through" the passage with such a view.

Since the extended profile alone does a poor job of explaining the relationships between passages, do you ever include references that can help the viewer to quickly find the same point on the plan and profile? How do you handle multiple passages on the same level, or passages that crisscross one another vertically. For example, how would you show an extended profile of a cave laid out like this, an imaginary plan view with the numbers representing depth below datum:
Image
Seperate the sections?
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Re: Extended profiles

Postby Martin Sluka » Jun 25, 2014 3:48 am

GroundquestMSA wrote:Since the extended profile alone does a poor job of explaining the relationships between passages, do you ever include references that can help the viewer to quickly find the same point on the plan and profile? How do you handle multiple passages on the same level, or passages that crisscross one another vertically. For example, how would you show an extended profile of a cave laid out like this, an imaginary plan view with the numbers representing depth below datum:
Seperate the sections?


I use the same principle as with map - move parts, which overlap and connecting lines. But it all depends on particular situation.

Image

Example - the centerline is not suitable for extended elevation. But few commands correct it:

data nosurvey from to
18.2 18.5

data normal from to compass length clino
extend ignore
18.2 18.3 15 13.72 +23.1
18.3 18.4 280 14.27 +23.4
18.4 18.5 188 11.29 +19.8
extend left
18.5 18.6 271 10.16 +28.4

It means that there is created calculated fake survey 18.2-18.5 and all shots from 18.2 to 18.5 are ignored. So the centerline for extended elevation will go from 18.2.to 18.5 and 18.5-18.9

Image
sketch

Image
map

Image
extended elevation
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