Thx for the feeback guys. About adding waves effects it was a quite tricky subject. Waves are white and to have a white line all around the islands seems perturbating for the relief effect (for me low is dark and high is white). On that one i actually tried to add some waves but white was too strong and i end up soften so much the effect that it isn't visible anymore. I was quite happy with the relief of the island and didn't want to take any risk of decreasing the lisibility of the relief feeling with a white line around so i give up on the wave effects, a challenge for another map i guess