A re-do of The Chessman's Mark old map

[JhekieJ]

In many programs, the default light direction for light/shadow effects is from the northwest / upper right. (135 degrees on the mathematical unit circle.)
That gives shadows cast to the southeast / lower left.

Ah, but my observation was from very old maps, dating to 15-1600s. Maybe the programs were based from this too?

[bkh1914]

Ah, but my observation was from very old maps, dating to 15-1600s. Maybe the programs were based from this too?

I think you are right.

I was looking at NASA satellite images once and they had an explanation of why most people have trouble reading the shadows correctly.
If I remember correctly, it went something like this:
In the northern hemisphere, the light in satellite images is from the south and the shadows are to the north, but people are accustomed to seeing shadows from the other direction on maps.
I also wonder how that precedent was set.

[waldronate]

I also wonder how that precedent was set.

I recommend invoking laziness as it's rarely wrong: it's easier for Western and right-handed people to color the right-hand sides of things moving from top to bottom on the page, and coloring makes those sides darker. The light will naturally come from the upper-left in that case.

[qhqhTerra]

It is an interesting map!
For me this map looked like a boundary between a swamp and the sea.
It also looked like a fjord or ria coast.

If it is a very shallow sea, it may be possible to find coral reefs in warm climates.
If this is a broad swamp, there will probably be a special ecosystem and culture in this area.

[Kellerica]

I recommend invoking laziness as it's rarely wrong: it's easier for Western and right-handed people to color the right-hand sides of things moving from top to bottom on the page, and coloring makes those sides darker. The light will naturally come from the upper-left in that case.

An excellent point and I wouldn't be one bit surprised to find it be accurate.