Terrain data is coming from Mapzen's global terrain tiles. Multiplying this scale factor by the width of a 3D mesh in units x will tell you how high in units z your mesh should be after displacement in order to be true-scale. ( Here's a tutorial for doing this in Blender.) We recommend Unreal 4096×4096, Unreal 2048×2048, and Unreal 1024×1024, for High, Medium, and Low resolution options. Click the resolution dropdown and use one of the existing presets. (You may need to right-click the image to do this.)
Here's a blog post about this tool, with more explanations and examples! The result is a grayscale heightmap, suitable for use as a displacement map in 3D applications.
This is an elevation data browser, which 'auto-exposes' the display so that the highest and lowest visible elevations are white and black.
