# 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.

- **Patent:** US 7158878
- **Original title:** Digital mapping system
- **Owner:** Google LLC
- **Granted:** 2007
- **Status:** Public domain (expired)
- **Times cited:** 399
- **Field:** software, consumer_electronics, telecommunications, geospatial

## What it does

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 does NOT 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.

## Real-world examples

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

## 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.

## Frequently asked questions

### What does How Digital Maps Are Built From Small Image Pieces cover?

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.

### Who owns patent US 7158878?

Google LLC owns this patent, granted in 2007.

### When does this patent expire?

This patent is expected to expire on January 2, 2027, when the invention enters the public domain.

### What is patent US 7158878 cited by?

This patent has been cited by 399 later patents that build on its ideas.

### What problem does this patent solve?

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.

### What does this patent NOT cover?

Displaying a single, unbroken map image file without assembling smaller tiles.

**Full plain-English explainer:** https://patentbrief.org/patent/us/7158878/google-maps-directions

**Original patent:** https://patents.google.com/patent/US7158878

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_Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._