Interior walls?

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Interior walls?

Postby GroundquestMSA » Jul 22, 2013 8:08 pm

I'm trying to draw a map and have a question. The cave I'm working on has several small loops that result in little "islands" of bedrock, as seen on the map. There are also a few big slabs of breakdown that I have included on the map. I'm wondering if anyone has any tips on how to clearly distinguish these interior "islands" from breakdown. I usually try to add some sort of additional dimension to big breakdown, and use a smaller line width, but as I was sketching, I realized that a viewer unfamiliar with the cave might mistake some of the features. I tried adding another set of lines to the islands, but that looks goofy. I also don't really like the brick pattern sometimes used.

Any suggestions? Remember that I'm working with pens and paper.

Here is the sketch I was playing with yesterday. It is incomplete and has to be redrawn anyway, but take a look at it and tell me how you would tackle it.
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Re: Interior walls?

Postby gindling » Jul 22, 2013 8:32 pm

That's a good question. I have used 45 degree slanted lines to indicate bedrock pillars, which didn't really look all that good. The "brick" pattern is the standard fill for limestone in stratigraphic profiles, but can seem out of place. What I found works best is to mark them with one of the above patterns on the survey sketch and then when you draft the map use line width. Heaviest pen for cave walls and bedrock pillars. Medium pen for lettering and legends and what not. Finest pen for map detail like slope lines, speleothems, floor detail, etc.

Just a question, why is your compass pointing south? Its usually standard to have the N arrow pointing up on a map unless you have to finagle the map to fit the page. I dodn't know if there is a reason or not, I've been called out for it before. It just doesn't seem needed in your sketch to make the cave fit the page.

Looking good!
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Re: Interior walls?

Postby GroundquestMSA » Jul 22, 2013 9:02 pm

gindling wrote:Just a question, why is your compass pointing south? Its usually standard to have the N arrow pointing up on a map unless you have to finagle the map to fit the page. I dodn't know if there is a reason or not, I've been called out for it before. It just doesn't seem needed in your sketch to make the cave fit the page.


I too have been counseled on the proper use of the North arrow. In this case, the map was sketched "upside down" during the survey, just because it was more natural, given the location of the entrance and direction of travel. This means that all of my cross sections are drawn to fit this orientation and I'll have to flip them around in order to "do it right". I may end up turning the map around, but in my opinion, it really makes little difference. Many older maps had north arrows pointing in all possible directions, I'm not sure when or why that became "wrong". Perhaps the best reason to keep north up is that it's expected, and the reader may assume that north is up and not bother looking at the arrow.

Line widths do seem the best way to clarify things, but I don't know that I have a large enough variance between pens to make the difference obvious. I don't want to make the walls enormously chunky...what pens do you use?
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Re: Interior walls?

Postby gindling » Jul 22, 2013 10:14 pm

I like the Pigma Micron series of archival ink pens. I usually use a .75mm, a .5mm, and a .35mm or .25mm pen for my three sizes. The 1mm just seems too clunky. The only reason I use the archival inks is so my originals will last in case of some EMP, super conductor eating bacteria, or whatever that shuts down all the 'puters and E-files. (Kinda kidding, I read too many Larry Niven novels..) You could of course just get cheaper pens of the same sizes and digitize them for posterity.


Here is one of the first maps I did with the pens, and before I learned of the blue grid graph paper where the blue grids disappear after copying, hence the wobbly lettering!
Image
Damn those N arrows, do what you seem is best is what I've come to agree with.
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Re: Interior walls?

Postby Chads93GT » Jul 22, 2013 10:40 pm

Black the islands out completely.
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Re: Interior walls?

Postby Extremeophile » Jul 23, 2013 9:27 am

In most cases using a heavier weight line for passage walls vs breakdown or other in-passage features will make it clear. It also helps to have lots of floor detail such that the passage is full of patterns, whereas the bedrock pillars are simply white. Here's an example from a portion of Mammoth Cave:

Image

and here's the same area showing how I indicate pillars during the sketch, so that it's obvious to a cartographer:

Image


In more complex areas I've sometimes used the diagonal hatch marks to indicate bedrock pillars, as in this example from Carlsbad Cavern.



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Last edited by Extremeophile on Jul 23, 2013 9:50 am, edited 1 time in total.
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Re: Interior walls?

Postby trogman » Jul 23, 2013 9:49 am

The NSS map symbols uses a 45 degree cross-hatching method as shown under pillar(bedrock). http://www.virginiacaves.org/images/NSS-Symbols1.gif I think this is what gindling was talking about in his post.
gindling wrote: I have used 45 degree slanted lines to indicate bedrock pillars, which didn't really look all that good.


As far as having the north arrow point up, you can do it as you see fit. However, I will say that it is very counterintuitive to have it pointing down, and it can cause a lot of confusion and frustration to map readers! (I have personal experience with this, if you couldn't tell)

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Re: Interior walls?

Postby Extremeophile » Jul 23, 2013 3:00 pm

Here's another example from a cave here in Colorado where a floor detail pattern and different line widths create contrast between passage, breakdown and bedrock pillars.


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Re: Interior walls?

Postby gindling » Jul 23, 2013 4:48 pm

Damn, Iove those multiple passage cross section views. Really shows in perspective the lay down of the elevations of passages. I really like the computer drafted complex maps these days but after getting burnt on Inkscape and wasting days I've just stuck with the pens for simple cave maps. Are you all using Illustrator?
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Re: Interior walls?

Postby JSDunham » Jul 23, 2013 5:03 pm

I'm using Illustrator now, having switched when I started working on my first large map. I am mostly mapping recent and ongoing discoveries, and I succumbed to the allure of being able to make a nice working map and edit as more things are discovered without redrafting the entire thing. It also allows me to draft-as-I-go, which I am doing on a current project, rather than letting a bunch of work pile up until the end of the survey.

But, on the main topic of bedrock pillars, the maps I am doing have quite a lot of them. The solution I have been using is line weights combined with the outer glow function in Illustrator, which gives the cave passage a sort of fading shadow on the outside, as in this example. I can't say I am fond of the hash marks, diagonal line fills, or solid black fills; they do not really agree with my sense of artistry, though they are certainly effective. If drafting by hand, I think I would prefer line weights or line weights combined with an appropriate bedrock symbol above anything else.

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Re: Interior walls?

Postby GroundquestMSA » Jul 23, 2013 7:11 pm

Thanks everyone for the advice and for showing me your maps. I'm a bit ashamed of these scribbles after looking at such neat work. Nonetheless, here they are. I tried two different methods; since I used my biggest pen to do the walls and it didn't seem clear enough, I sloppily retraced the islands to bold the lines (example 1). If I had a bigger pen and cleaner lines this may work. In the second example I shaded the islands with the marvelous technological advance known as MS Paint, which I use for lettering. Both solutions are a bit distracting, but they do the job (practically, not aesthetically speaking). I also flipped the map so that Brewer wouldn't be confused :tonguecheek:
Some day I'll learn to do this with one of them there fancy computer programs, maybe. Until then, I'm interested in knowing if anyone else uses pens to draw maps, which ones they use, what they cost, and where you buy them.

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Re: Interior walls?

Postby Chads93GT » Jul 23, 2013 8:43 pm

Your map looks much better aligned due north. Some cartographers I know here in Missouri black "pillars" in (how I learned) and others dont. I recently changed the pillars in my current project and added the bedrock symbol to see if I like it and I am not sure how I feel about it yet.

See the center of this map cut.
Image

As for pens for drafting, too many steps to do it correctly IMO, from the conversations that I have had with a guy here in Missouri who has drawn hundreds of miles of caves with pen (since the 60's) and yeah, screw that! much cheaper to do it on the computer lol
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Re: Interior walls?

Postby Chads93GT » Jul 23, 2013 8:46 pm

As far as distinguishing from breakdown, this is how I draw breakdown and distinguish it from any bedrock pillar.


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Re: Interior walls?

Postby Bob Thrun » Jul 24, 2013 2:50 am

The use of heavy lines to delinate interior walls or bedrock pillars is a good idea. However, the exterior walls should be just as heavy. The walls should be the heaviest lines on the map.
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Re: Interior walls?

Postby JSDunham » Jul 25, 2013 11:23 am

Agreed, same bold on all walls.

I really like your shading in the pillars, though, with that particular map. It certainly makes the cave passages stand out. It would make them stand out even more if you had shading around the entire outside of the walls, though I don't know how one could do that and make it look good in paint.
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