How Digital Maps Are Built From Small Image Pieces

Google's 2007 patent on how to assemble small map images, called tiles, into a larger map view on your device, enabling smooth zooming and panning.

What it covers

This patent describes a system for creating digital maps that you see on your screen. Instead of sending one giant map image, it breaks the map into many small square images called 'map tiles.' When you request a map area, your device asks a server for the specific tiles it needs. The device then stitches these tiles together into a grid, aligns them within a viewing area (a 'clipping shape'), and shows you the map. If you zoom in or pan, it requests new tiles and reassembles them. It can also add extra information like markers or directions as overlays on top of the map tiles.

What it doesn't cover

• —Displaying a single, unbroken map image file without assembling smaller tiles.
• —Maps that do not use a server to provide the map image data.
• —Systems that do not align the assembled tiles within a specific viewing boundary.
• —Methods that do not allow for zooming or panning by requesting new tiles.
• —Displaying a map without the ability to overlay additional information like markers or directions.

The clever bit

The core innovation was a standardized way to request, assemble, and display map data using small, manageable 'tiles.' This allowed for smooth user interactions like panning and zooming without needing to reload the entire map, making digital maps practical for widespread use.

Why it matters

This patent is foundational to how virtually all modern online mapping services function, including Google Maps, Apple Maps, and others. The 'tile-based' approach it describes is essential for efficiently delivering map data to billions of users on devices with varying screen sizes and internet speeds.

Real-world examples

• 1.Google Maps
• 2.Apple Maps
• 3.OpenStreetMap
• 4.Most web-based mapping applications