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To have or not to have contour labels

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#1
rockieshome

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Hello everyone,

I'm having some difficulty making a particular decision and would like to poll members for a wee bit of help making it.

I'm currently in the process of completing a large hill-shaded relief map of mountainous terrain that also includes contour intervals and am currently struggling with the idea of whether to label the contour elevations or not. The map is not necessarily intended for navigational purposes, nor is it of a scale (1:200 000) that allows for precise determination of x, y, or z values. I am also including a 10km grid to allow the user to at least derive some reasonably accurate coordinates should so desire, and many peak and spot elevation values have been added. The map’s text also identifies a 200m contour interval. The disclaimer clearly states that the map is not to be used for navigation or to derive precise geographic coordinates. Its main intent, however, is to aesthetically represent the landscape in a formal cartographic format, and help the user get a sense of the landscape's morphology and their place in it.

I try in most cases to follow very stringent cartographic standards regarding function, but also very much believe in the artistic and aesthetic elements of form in map design and and with this one am having some challenges finding that balance. In this case I'm leaning a bit more toward form and not labeling the contours at all, despite their obvious functional importance, because I think this map looks much better without them.

I've looked through my map archives and to be honest, haven't found many that didn't label contours, so maybe that renders my question moot. However, most of the same maps are relatively technical with respect to cartographic function and what information the user might presume to derive from them. With my map though, not labelling the contour lines and deleting the gridlines and coordinate labels might help to avoid any confusion that the map might be used to extract geographic or elevation values. I’d like to keep the peak and spot elevations to give a sense of height and the contour interval 200m definition, which I believe lend a sense of the landscape’s ruggedness.

I therefore pose the questions… might this be a case where form can and should trump function? Would a decision not to label contour intervals be strengthened by also not including gridlines and coordinate labels? What about keeping the spot elevations and the mention of the contour interval spacing?

Hopefully my conundrum is clear and that I've provided enough information, but if anyone requires more, please don't hesitate to ask. Sorry if this seems long-winded, and if the answers seem moot to some, but I’m printing several thousand copies and would like at least to get it right the first time…

Many thanks to all who take the time to respond...

r

#2
Hans van der Maarel

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A contour line is useless if you don't know at which elevation it is. You don't have to label all of them, one in five would do just as well (then the map reader can deduce the intermediate contour values). Making the one that you label a bit thicker than the rest can be useful too.
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#3
frax

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Hans,

It is not useless without labels - it helps to communicate the topography and primarily the slope and steepness. Rocky, I would vote for leaving them off!
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#4
Hans van der Maarel

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It is not useless without labels - it helps to communicate the topography and primarily the slope and steepness. Rocky, I would vote for leaving them off!


Well, okay, not totally useless, but if you have no indication of what's up and what's down, there's little benefit in knowing slope and steepness. With just spot elevations to go by, it's difficult to get a good idea of the topography (unless there's other aids, such as shaded relief, and even then it's difficult), hence my position for labels.
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#5
Martin Gamache

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I guess the main questions are should you even have contour lines?
If you do, are the spot labels sufficient? If not, then yes add some contour labels to fill in where necessary. I think the main goal should be to have consistent elevation label density across the sheet so the user does not have to trace or count lines for too far.

There are some cases of contour maps without elevations working quite well, orienteering maps are probably the best example. But they tend to be very large scale and provide alot of other navigational aids. Nevertheless I have been known to confuse up with down on the map during a race.

I would suggest taking a look at a swiss topo 1:200k sheet http://www.swisstopo...alog/maps/tk200. They don't have a huge sample there, but maybe going to a map library to check out one of the sheets would give you some good ideas. I'm not sure where you are located but if you are lucky there might be a good college map library not too far. I won't have access to my sheets for another 2 weeks, but I may be able to scan a section for you then, someone else on here may be able to do so before then.

Also I do not have access to the chapter on contour lines in Imhof at this moment but if you want more precise rules that would be a good place to start.


I did use a NTDB sheet (Canada) at 1:250k a few weeks ago in the field and it had some but few contour labels and it seemed to work ok, we would of preferred a few more, this was on a driving trip.

You should of course post a sample for us to look over.

Good luck.

mg

#6
Pete

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If you want to show landforms without actually conveying height information use a composite of hillshading and slope: using contours without labels seems a little extreme and it can be visually overwhelming.

I've attached a map where contours are shown only in areas of excessive slope (greater than 1 in 7).

If you combine a layer of hillshading with a greyscale layer os slope then you can represent major landforms very effectively and the layer of slope will show the details on the sunlit and otherwise detail-less slopes. Using more generalised hillshading will result in a smoother-looking terrain but you might want to vary the detail of your hillshading with height.

It is very hard to know what to do. I'll admit to never having made the same map twice!

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