Minecraft Update 1.8's World Customization feature previewed
Mojang has released a new video previewing Minecraft's World Customization feature. Arriving on PC with update 1.8, the World Customizer will allow you to create your own terrain.
The video demonstrates the feature, which includes 16 different sliders that will affect various aspects of Minecraft's terrain generator, including biome depth, height and weight, as well as the field's depth of noise. You will be able to adjust the sliders according to your preference or input the exact value directly, give you complete control over things like the sea level and what structures you want to generate.
According to the YouTube description, Mojang will also provide seven preset terrain options in the update that they think players will find "interesting." Some of these options will include a world made of water up to the top of the map, and the return of floating islands.