Generate a topographic map background

Contour lines, traced not filtered

A contour map is a landscape read as lines of equal height. This page invents the landscape, samples its height on a grid, and traces where each level crosses that grid. Twenty-four levels, with every fifth one drawn heavier, the way an index contour is on a real map.

The tracing is the reason it holds up at 6K. The obvious way to make a field like this is an SVG noise filter, which looks right in a thumbnail and falls apart at wallpaper size: the filter works in eight bits, so what comes out is blocky rectangles and staircase edges. Lines worked out as geometry have no precision to run out of, and they land on whole pixels at any size you pick.

One landscape, seen from different distances

The heights come from the coordinates themselves, hashed, with no seed and no random numbers. The same size and the same relief give you the same map every time, and a bigger size shows you more of the same country rather than a new one.

The Relief slider is how much of that country the frame holds. Low is a few broad hills with wide spacing. High is dense terrain with lines close together.

PNG or SVG

The PNG is painted here, at the size in the dock, and saved to your downloads folder. The SVG is two paths, so it scales to any size afterwards and stays a few kilobytes. Both are yours, with no watermark on either.

Behind a recording

Prequel ships this map as one of seven drawn backgrounds in its editor, where it is traced again at the export's own resolution. Record your Mac's screen, and the editor opens with the zooms already placed, your camera framed and a background behind it.