High-resolution vector shaded relief

Terrain-RGB raster tilesets originally developed by Mapbox contain elevation data encoded in raster PNG tiles as colour values that can be decoded to raw heights in metres. These tilesets are used for a wide variety of applications, notably for styling terrain slope and hillshades so that terrain can be rendered in three-dimensions.

Terrain-RGB tilesets usually use the well-known PNG format that effectively involves lossless compression. Consequentially, compression or a special file format is not needed. An image is saved as PNG tiles for each zoom level where the three PNG channels allow 3 bytes of storage per pixel instead of the usual minimum of 4 or 8 bytes per pixel.

It was known as long ago as 2018 that hillshades (shaded reliefs) generated from terrain-RGB tilesets using mapbox-gl, the precursor to maplibre-gl, displayed artifacts called "artifical visual lines" at zoom levels above about 15.5 even for a nominally high-resolution Digital Elevation Model (DEM).