Overview

OMN4 lets you view maps online, download maps for offline use, and manage stored map data from one place. The map layers you can use depend on your account, the area you are in, and whether a map type is available for viewing, downloading, or both.

This section explains how maps are organised and where to go next for the detail.

In this section

• Map Types and Scales explains the map layers available in OMN4, what their scales mean, and why some map types are used for viewing while others are mainly used for downloading.
• Map Management shows how to add areas, download or remove maps, review storage, and verify downloaded files.
• Download Maps focuses on saving maps for offline use.
• Streaming vs Offline explains when OMN4 streams map data and when it uses downloaded files instead.
• Storage and Verification covers where downloaded map data is stored and how to check it if something looks wrong.

How maps are organised

OMN4 works with two main ideas:

• Map types are the layers themselves, such as OS 1:25,000, OS 1:50,000, imagery, or height data where available.
• Areas are the places those maps apply to, such as Great Britain, France, or other supported regions.

That means the same area can offer several map types, and the same map type can be available across more than one area.

Viewing maps and downloading maps

Some map types can be both viewed on the map and downloaded for offline use. Others are mainly managed through Map Management.

In practice, this means:

• the map you are currently looking at is not always the same as the map data you are downloading
• some map data is intended for offline use or background data rather than direct viewing
• Map Management is the place to see what is available for an area and decide what to keep on your device

Online and offline use

When a map is not stored locally, OMN4 can use streamed map data if your settings and connection allow it. When you download a map, OMN4 stores that map data on your device so you can keep using it with a poor connection or no connection.

Downloaded map data can take up significant space, so OMN4 also gives you tools to:

• review which maps and areas are stored
• remove map data you no longer need
• change storage location where supported
• verify downloaded files if they seem incomplete or incorrect

Good starting points

Start with the page that matches what you are trying to do:

• If you want to understand the different map layers, go to Map Types and Scales.
• If you want to save or remove maps, go to Map Management.
• If you are deciding between live map access and offline storage, go to Streaming vs Offline.