Heightmap Editor

File

Tip: large (8k) maps need a modern browser and plenty of RAM.
Brush
Raise
Lower
Smooth
Erode
Constant
Flatten
Noise
Ridge
Paint with left mouse. Alt+click samples height for Constant brush. Hand pan: hold Space and drag, or middle mouse drag.
View
Heightmap
Topo
Atlas
Topo view uses sea level to separate water and land. Zoom in for fine editing; pan to move around.