Render relief

[cyclosm]

Render relief

[Phyks]

Actually, we can probably directly use https://github.com/der-stefan/OpenTopoMap/blob/master/mapnik/HOWTO_DEM.md. Note that relief data for the entire world should be about 500GB apparently.

[Phyks]

First basic version of hillshades based on the OpenTopoMap code is available in Phyks@b0e5c88.

I have two versions, not sure which one is better.

First option is

with a very strong hillshades overlay.

Second option is

using the OpenTopoMap approach of redrawing landuse on top of hillshades to make them softer.

What do you think?

[Phyks]

Useful links for this:

https://tilemill-project.github.io/tilemill/docs/guides/terrain-data/ and https://github.com/abyrd/velosm#elevation

[Florimondable]

Look great !

Not sure to understand how it's rendered.
First option : render the map then add the shaded texture, so everything is shade (building, names, land...) ?
Second option : render the landuse, add the shaded texture, render the landuse, render other layers ?

For the result I prefer the first option as the contrast is higher and even in the city we can see the relief.
Eitherway we must able to see the relief in the city, it's one of the issue with opentopomap.

[Phyks]

First option is without the landuse_over_hillshade layer (Phyks@b0e5c88#diff-2d6c6d06f63a6fab47286addedefc335R148). Just draw the landuse, put hillshades on top, draw the rest on top.

Second option is the full commit Phyks@b0e5c88. Draw the landuse, draw hillshades on top and redraw the landuse in a lighter way on top of it.

This is what OpenTopoMap is doing, but I'm not convinced this is really useful so far https://github.com/der-stefan/OpenTopoMap/blob/master/mapnik/opentopomap.xml#L183-L201.

[Phyks]

Fixed :)