3 ms·

But if you try using the factually correct angle (light from some angle in the south), the result is misleading to the eye.

by mdp2021 4y ago

pixelesque 4y ago
Sometimes, but not always: it likely depends on the style of the map and how accurate it is as well I think, and maybe depends on people's perception: thanks to computer UI buttons from the 90s, it is common for upper and left-most surfaces/bevels to be lighter, so there is some assumption there. i.e. I think this type of thing: https://cartographart.com/minimalist/iceland_2_5k_orth_occlusion.jpg https://cartographart.com/minimalist/iceland_2_5k_orth_occlu... works well, but that's not really a detailed map with normal cartographic details like roads and towns on overlaid with relief shading, so difficult to say. However even if you do try and do it accurately, places on the equator are likely troublesome: i.e. the whole of Africa or something: you're unlikely to want to do the fully-accurate thing there of above the equator (or where the sun is) being shadowed from the south and below the equator being shadowed from the north, it'll likely be confusing in the middle.
- mdp2021 4y ago
  > depends In fact it works with the provided example but, empirically, it does not on area detail of detailed maps. Crests and valleys will switch. > computer UI buttons That is a consequence of consolidated established style, not a cause. > the whole of Africa It will work on the view of the full shape but it will not on the area detail, where the viewer will lose the notion of global position and attempt to interpret it like any other spot.
  - pixelesque 4y ago
    > In fact it works with the provided example but, empirically, it does not on area detail of detailed maps. Crests and valleys will switch. I don't think that's always the case though: I think it's likely similar to optical illusions: you can technically correctly see it both ways, but it depends on the person's brain and what they're used to as to how their brain sees it. > That is a consequence of consolidated established style, not a cause. I didn't say it was a cause, I said that it might lead people to be able to more readily recognise top/left as the lighting direction more readily as "raised" due to being used to computer UIs having top/left being lighter signifying raised elements, and them being more familiar with it that way.
    - mdp2021 4y ago
      > always the case Try it. In my initial experiments as a cartographer, as is normal for learners I did "fix it", and tried "boreal morning or afternoon real light directions": the effect will be wrong, in an actual map. ...Learners "make it the right way" and learn that the """right""" way is wrong. > more readily Sure consolidated UIs will contribute in the spiral of circular consolidation of natural ("brain") patterns and conventions, but the "light from top-left" use predates UIs by very many centuries: when we read a document it is more typical to have it lit, not darkened by one's own shadow from a body interposed between sun and document; when we gather around a fire we face it.
eloisant 4y ago
Why is that misleading?
- contravariant 4y ago
  Probably because the predominant direction of light is the south. That would mean lighting it from below, which looks unnatural because we're used to stuff being lit from above.
  - mdp2021 4y ago
    Congratulations! A good instance of the very simple explanations and theoretical solutions that, "hiding in plain sight", manage to possibly remain unseen for a very long time. I nearby noted that "you do not cast your shadow on your documents" and that "you gather around a fire facing it". There is something even simpler: ___ the sun is above. ___ So, to represent something with a light coming from "the south" is as unnatural as lighting a face from below.

But if you try using the factually correct angle (light from some angle in the south), the result is misleading to the eye.

pixelesque 4y ago

Sometimes, but not always: it likely depends on the style of the map and how accurate it is as well I think, and maybe depends on people's perception: thanks to computer UI buttons from the 90s, it is common for upper and left-most surfaces/bevels to be lighter, so there is some assumption there. i.e. I think this type of thing: https://cartographart.com/minimalist/iceland_2_5k_orth_occlusion.jpg https://cartographart.com/minimalist/iceland_2_5k_orth_occlu... works well, but that's not really a detailed map with normal cartographic details like roads and towns on overlaid with relief shading, so difficult to say. However even if you do try and do it accurately, places on the equator are likely troublesome: i.e. the whole of Africa or something: you're unlikely to want to do the fully-accurate thing there of above the equator (or where the sun is) being shadowed from the south and below the equator being shadowed from the north, it'll likely be confusing in the middle.

mdp2021 4y ago
> depends In fact it works with the provided example but, empirically, it does not on area detail of detailed maps. Crests and valleys will switch. > computer UI buttons That is a consequence of consolidated established style, not a cause. > the whole of Africa It will work on the view of the full shape but it will not on the area detail, where the viewer will lose the notion of global position and attempt to interpret it like any other spot.
- pixelesque 4y ago
  > In fact it works with the provided example but, empirically, it does not on area detail of detailed maps. Crests and valleys will switch. I don't think that's always the case though: I think it's likely similar to optical illusions: you can technically correctly see it both ways, but it depends on the person's brain and what they're used to as to how their brain sees it. > That is a consequence of consolidated established style, not a cause. I didn't say it was a cause, I said that it might lead people to be able to more readily recognise top/left as the lighting direction more readily as "raised" due to being used to computer UIs having top/left being lighter signifying raised elements, and them being more familiar with it that way.
  - mdp2021 4y ago
    > always the case Try it. In my initial experiments as a cartographer, as is normal for learners I did "fix it", and tried "boreal morning or afternoon real light directions": the effect will be wrong, in an actual map. ...Learners "make it the right way" and learn that the """right""" way is wrong. > more readily Sure consolidated UIs will contribute in the spiral of circular consolidation of natural ("brain") patterns and conventions, but the "light from top-left" use predates UIs by very many centuries: when we read a document it is more typical to have it lit, not darkened by one's own shadow from a body interposed between sun and document; when we gather around a fire we face it.

eloisant 4y ago

Why is that misleading?

contravariant 4y ago
Probably because the predominant direction of light is the south. That would mean lighting it from below, which looks unnatural because we're used to stuff being lit from above.
- mdp2021 4y ago
  Congratulations! A good instance of the very simple explanations and theoretical solutions that, "hiding in plain sight", manage to possibly remain unseen for a very long time. I nearby noted that "you do not cast your shadow on your documents" and that "you gather around a fire facing it". There is something even simpler: ___ the sun is above. ___ So, to represent something with a light coming from "the south" is as unnatural as lighting a face from below.