Made some progress on procedural terrain generation: now adjacent biomes blend together using perlin noise, and their procedural map will get additional features from them. Also now the generator add a coastline if the current biome borders with the ocean, water level changes according to tides and the various scattered seashells changes with each tide.

When i'll generalize this terrain generator to work with other planets other than Earth, the tide level will be influenced by the number and masses of moon around the planet or by the mass of a gas giant the planet is orbiting around, i also plan to support other types of oceans for alien planets, like liquid methane, lava, ammonia and...oil.