Cartography

General cycling advice ( NOT technical ! )
pwa
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Joined: 2 Oct 2011, 8:55pm

Re: Cartography

Post by pwa »

Pendodave wrote: 5 Jan 2022, 4:45pm While i ubderstand that shading is a lovely thing on maps used for decoration, i fail to see what it adds to a map being used for navigation. Those french topo maps are just cluttered up with shades and colours. I dont thunk think I've ever looked at an OS map and thought "if only it had lots of shading on"
This is very much inho of course, and perhaps influenced by my 1st year cartography and drawing practicals involving proper ink and drawing film...
I agree. In practice it doesn't do much to help you work out exactly where your climbs are and how long they will be. Only contour lines and chevrons help with that.
Mike Sales
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Joined: 7 Mar 2009, 3:31pm

Re: Cartography

Post by Mike Sales »

pwa wrote: 5 Jan 2022, 5:23pm
I agree. In practice it doesn't do much to help you work out exactly where your climbs are and how long they will be. Only contour lines and chevrons help with that.
On my first ride in France I remember riding up a pass in the Juras, leading to Geneva. The gradient was easy, but I noted chevrons ahead on the map, so I prepared for a steep pull. I was pleasantly surprised to round a bend and see the summit buildings ahead. No 1 in 5 at all!
One does have to learn the cartographers' conventions.
Last edited by Mike Sales on 5 Jan 2022, 5:58pm, edited 1 time in total.
It's the same the whole world over
It's the poor what gets the blame
It's the rich what gets the pleasure
Isn't it a blooming shame?
simonhill
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Location: Essex

Re: Cartography

Post by simonhill »

I'm sure other maps do it as well, but Google maps have 3 useful views. It shows flat map, topographic map which has hill shading or contours if you zoom in and satellite view. I use all 3 when planning my route. Nonetheless, I do love something like an OS map as I can work out most of what I want.

In God's chosen county of Essex the sun sets in the NW in summer. In the UK's blighted winters, I never see the sun, so don't know where it sets.
nirakaro
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Joined: 22 Dec 2007, 2:01am

Re: Cartography

Post by nirakaro »

pwa wrote: 5 Jan 2022, 5:23pm In practice it doesn't do much to help you work out exactly where your climbs are and how long they will be. Only contour lines and chevrons help with that.
Certainly that's true. However I do think the shading gives a good intuitive lie-of-the-land impression.
ChrisF
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Joined: 22 Mar 2014, 7:34pm

Re: Cartography

Post by ChrisF »

Shoogle wrote: 4 Jan 2022, 4:45pm On terrain maps, why are the shadows on the south side of hills?
solarpanels.png
solarpanels.png (77.67 KiB) Viewed 496 times
Probably the same reason that solar panels ae pointing NW on the latest OS maps....
Chris F, Cornwall
Psamathe
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Joined: 10 Jan 2014, 8:56pm

Re: Cartography

Post by Psamathe »

nirakaro wrote: 5 Jan 2022, 6:32pm
pwa wrote: 5 Jan 2022, 5:23pm In practice it doesn't do much to help you work out exactly where your climbs are and how long they will be. Only contour lines and chevrons help with that.
Certainly that's true. However I do think the shading gives a good intuitive lie-of-the-land impression.
I would agree. I find the shading helpful to get a broad impression of e.g. a longer route (you can very quickly see if the route is running along a valley or if up and down over every hill) but as you look in more detail I sub-consciously switch to using contours and the shading does not get in the way. So for me it has pros without cons.

Ian
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Chris Jeggo
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Location: Surrey

Re: Cartography

Post by Chris Jeggo »

Agreed. Which way shall I ride today? How energetic am I feeling? Shall I ride with the grain of the land, or across it? Hill shading helps you to decide.
wjhall
Posts: 265
Joined: 1 Sep 2014, 8:46am

Re: Cartography

Post by wjhall »

... wrote: Thanks for the example.

... the result is that the light appears to come from the north-west. Although this is unrealistic lighting in the northern hemisphere,... ...
https://en.wikipedia.org/wiki/Terrain_c ... ded_relief
...
Perception may be the real reason, but the sun does get into the NW in the northern hemisphere, although probably the length of the shadows on the map is reduced compared to reality.
Mike Sales
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Joined: 7 Mar 2009, 3:31pm

Re: Cartography

Post by Mike Sales »

Are there any enthusiasts for hachuring, an older depection of relief?
Hachures.gif
It's the same the whole world over
It's the poor what gets the blame
It's the rich what gets the pleasure
Isn't it a blooming shame?
ChrisButch
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Joined: 24 Feb 2009, 12:10pm

Re: Cartography

Post by ChrisButch »

There's a distinction between those cartographic devices which indicate a specific feature at a specific point, and those which indicate the general characteristic of an area. On OS maps, a church steeple is an example of the former, an area of scree the latter. Problems arise when the general obscures the specific. This is one of the shortcomings of the current OS 1:25k series, which are often guilty of obscuring contour lines with generalised ground surface indications. Admittedly this is more of a problem for hillwalking than cycling. The South Harris sheet is an extreme example.
wjhall
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Joined: 1 Sep 2014, 8:46am

Re: Cartography

Post by wjhall »

... wrote: ... one of the shortcomings of the current OS 1:25k series, ...
Another shortcoming of the 1:25k series, down in the marshlands, is that ditches take precedence over tracks, so a track marked on the 1:50k map can disappear on the 1:25k, and the ditches either side of it appear as fine blue lines instead. This has the interesting effect that when you might normally expect the 25k to give a better indication of whether a track is public, it can be less clear whether there is a track at all.
Bmblbzzz
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Re: Cartography

Post by Bmblbzzz »

Mike Sales wrote: 7 Jan 2022, 6:06pm Are there any enthusiasts for hachuring, an older depection of relief?

Hachures.gif
Yeah. I think of it as a version of shading before the development of widespread colour printing.

***

It would be great to have some input on this thread from our resident cartographer.
PDQ Mobile
Posts: 4659
Joined: 2 Aug 2015, 4:40pm

Re: Cartography

Post by PDQ Mobile »

Mike Sales wrote: 7 Jan 2022, 6:06pm Are there any enthusiasts for hachuring, an older depection of relief?

Hachures.gif
Not really.
It takes up too much space that other more important/interesting things could use.

I am a OS 1:50000 person myself. I like the use of some different colours and the larger area included on one single sheet against a 25,000.


I have done a fair bit of mountaineering and long distance trekking in the Alps, those Alpine maps are often (always?) shaded. I never really thought it offered that much advantage over close study of contour lines.

I prefer the OS over those Alpine maps, though they are undoubtedly very fine pieces of cartographic work.
Steep cliffs, gorges, and crags are marked differently on them, not simply shaded.
sjs
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Joined: 24 Jan 2010, 10:08pm
Location: Hitchin

Re: Cartography

Post by sjs »

wjhall wrote: 7 Jan 2022, 6:34pm
... wrote: ... one of the shortcomings of the current OS 1:25k series, ...
Another shortcoming of the 1:25k series, down in the marshlands, is that ditches take precedence over tracks, so a track marked on the 1:50k map can disappear on the 1:25k, and the ditches either side of it appear as fine blue lines instead. This has the interesting effect that when you might normally expect the 25k to give a better indication of whether a track is public, it can be less clear whether there is a track at all.
But by far the worst shortcoming of the 1:25k series is the giant size and vague location of the pub symbol.
sjs
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Location: Hitchin

Re: Cartography

Post by sjs »

PDQ Mobile wrote: 7 Jan 2022, 7:19pm

I am a OS 1:50000 person myself. I like the use of some different colours and the larger area included on one single sheet against a 25,000.
I think 1:50k is too large a scale for the amount of detail they show. As if they are just an expanded version of the old 1 inch to 1 mile maps they replaced, which they were, originally. And, the colour scheme is worse than the last version of the 1 inch maps as well.
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