Heightmap PNG-16 (Unreal / Unity / Blender)

A heightmap is a picture in which the brightness of a point means the elevation of the ground. Game engines build a landscape from it: they read the square canvas, stretch it over a given area and raise the vertices by the sample values. Sixteen bits per sample means 65,536 elevation steps instead of the 256 of an ordinary greyscale picture: at eight bits a slope breaks into visible stairs, at sixteen it stays smooth.

We deliver the canvas in two shapes at once, with identical content. The 16-bit PNG opens in editors and viewers; it is linear, without gamma and without a colour profile — here the picture is a carrier of numbers, not an image for the eye. The raw .r16 file is the same samples one after another, little-endian, with no header: that is what Unreal and World Machine expect, as they need no image parsing at all. The canvas side comes from the Unreal Engine landscape sizes: 505, 1009, 2017 or 4033 pixels, 1009 by default.

Three numbers necessarily travel with the file: the minimum elevation in metres, the maximum, and the ground side length of the area. Without them the file is useless — a sample on its own only means a fraction between the lowest and the highest point of THIS canvas, and the engine has nothing to convert it into metres with. The numbers are shown in the order status and written as plain text into heightmap_info.txt inside the archive, so the scale is not lost even if the file travels into a project and sits there for years.

Honestly about the terrain. Elevations come from the global Copernicus GLO-30 model: source nodes stand about 30 metres apart on the ground, and that step is visible on a game landscape — small landforms do not fit into it. Above 50, 60 and 70 degrees of latitude the dataset thins the sampling in longitude, so in the far north nodes stand further apart horizontally. Where there is no coverage at all (the open sea) the canvas arrives flat, and the order says so in words: a flat canvas looks like a healthy file, and staying silent about it would pass a placeholder off as a plain. A heightmap must be square, so the ordered frame is expanded to a ground square: everything you selected is inside, while the short side picks up adjacent terrain. The resulting square is named by a number too — its side length in metres. Elevation data: produced using Copernicus WorldDEM-30 © DLR e.V. 2010-2014 and © Airbus Defence and Space GmbH 2014-2018 provided under COPERNICUS by the European Union and ESA; all rights reserved.