MWM map files become 15-30% smaller when compressed with gzip.

So we can rather easily save on bandwidth and improve download speeds.

One approach is to use HTTP compression (e.g. Content-Encoding: gzip), it looks like this approach will require less changes to our code. However there likely to be issues with chunked downloads.

So a "custom" implementation seems to be more robust and will give more flexibility in e.g. choice of compression algo:

1. The maps generator compresses MWMs.
2. Clients download them and unpack immediately.

Also downloader's UI should be changed to display actual (reduced) download sizes (however it should display the final "disk" space taken by maps also), but it could be done as Phase 2.

Related to

• #5424
• #2317