Hillshading has got unnatural orientation

[xambroz]

Hello, it seems that on current rendering (2012/02/26) the hillshading has got orientation as if the sun would be on north-west from the hill. In my opinion it would be more suitable to put the sun's position south from the hill.

For example Rip - http://alpha.map1.eu/#zoom=15&lat=50.38559&lon=14.28793&layers=BTTT

On given example the shade is on the SE part of the hill, which would suggest that ligh source (Sun) is on the NW side of the hill.

This is bit unnatural as most of the day the sun would be southwards and not northwards from the hill.

Best regards Michal Ambroz

[bigr]

Yes, position of the light is north west. But this is common in hillshading. Motivation of this is not the real position of the Sun on the map. But common position of the light when you looking to the map. The map is mostly lighted from up than down.

[xambroz]

That's a pity - shading it as in real world rather than shading it as paper model in your hand would make it more usefull for the real orientation in terrain.

One of possible uses of such hillshading I can think of would be to use such map layer for easier orientation in terrain when flying (paraglide/ gliders/ ultralights ).

Best regards Michal Ambroz

[bigr]

Firstly, thank you for interesting discussion. I agree with you that for flying purpose it can be useful. But for many others I guess not. However there is I thing one more trouble with your usecase. The orientation of light depend on day and year time, and can differ 180 degrees. Even if the light will be rendered from the south , you will see completly different shading.

In the long term future I wont to render map directly on the client side with help of WebGL. I hope than it will be possible set user specific position of the light.

[xambroz]

To render the shade in separate WebGL with custom light position (for example follow the sun) would be definitely cool.