Mapterhorn is an open-source terrain data pipeline. Its core idea is deceptively simple: take the best available open elevation datasets from around the world, normalize them, and deliver them as a single, seamless, web-ready product.
From this unified dataset, Mapterhorn provides a ready-to-use map tile service designed for modern web mapping workflows. The terrain is packaged into PMTiles archives and exposed through a simple tile endpoint, allowing developers to request elevation tiles using standard z/x/y coordinates – just like conventional web map tiles. These tiles can be plugged directly into popular mapping libraries such as MapLibre or Leaflet, making it easy to power hillshading, 3D terrain visualizations, slope analysis, or elevation-aware routing. The PMTiles archives can also be downloaded and self-hosted, giving full control over performance and availability.
Roy's Military Map 1747-1752
I’ve created a demo MapLibre GL JS map that uses Mapterhorn to add a digital elevation model (DEM) to a vintage basemap. General William Roy’s Military Survey of the Highlands was the first systematic attempt to chart the rugged, inaccessible terrain of northern Scotland. The original is a hand-drawn watercolor masterpiece – and it practically begs to be draped over a DEM.
How the Demo Works
The demo uses a “sandwich” architecture that combines the strengths of MapLibre GL JS and Mapterhorn:
The Foundation (the DEM)
At the base is the digital elevation model served by Mapterhorn. This dataset captures the height of every glen and peak across the Highlands.
The Overlay (the Roy map)
Draped over this 3D surface is the Roy Highlands Survey, added as a raster tile layer and served by the National Library of Scotland. Because Mapterhorn normalizes elevation data into standard web-ready coordinates, the historic map aligns cleanly with the underlying terrain – allowing this 18th-century survey to sit seamlessly on a modern 3D landscape.
The Visualization
Using MapLibre’s terrain rendering, the scene is displayed in 3D. Roy’s hand-drawn hachures – lines used to indicate slope – now correspond with real shadows and elevation, reinforcing the landscape in a way the original map could only suggest.
Via: weeklyOSM
