The size of the complete OS map collection is about 16GB. While most computers or mobile devices can easily store this much data, it is not necessary to download the entire country. Memory-Map automatically downloads data on the fly and can also bulk-download a custom area. There are a few reasons why you might want to do this:
- Time. It takes a while to download the complete set. Downloading a region of interest (say, the entire North of England) is much quicker and more convenient.
- Reliability. Mobile devices fill up with data over time as you take photos and video, browse the web, etc. The operating systems treat these activities as a higher priority than long-term data storage by an app and will quietly remove data that has not been used for some. The larger the file, the more likely it is to be removed. We recommend you keep the storage no more than 80% full, and don't rely on operating system cleanup. The best practice is to bulk-download the area you need as part of you planning before leaving home. Even if you've already downloaded the whole country, you can do a bulk download to check the integrity of the data within the region, and make sure the data is still there.
England & Wales:
1:50k : 2.4 GB,
1:25k : 8.4 GB
Scotland:
1:50k : 1.4 GB,
1:25k : 4.4 GB