This map covers Sydney. Every pixel is coloured by the orientation of the local structure it sits on — the edges of roofs, walls, roads, and fences. The colour comes purely from the angle of that edge, not from what the object is.

Because a city block tends to be built on a single street grid, everything aligned to that grid lights up in the same hue. Across the city, grids of varying angle mosaic together — where one grid meets another, or streets bend to follow a ridge or river, the colour shifts. Patches of confident, uniform colour are strongly gridded; speckled, multicoloured areas are not.

Each tile starts as Nearmap vertical aerial imagery. It is converted to grayscale and run through a Sobel operator to estimate the edge direction at each pixel. The pixels are grouped into small spatial bins; each bin's dominant angle is then computed and encoded as a hue.