One of the neat feature that Nokia delivered as part of GDR2/Amber update was incremental updates for HERE Offline Maps data. With the Lumia Amber update installed on your phone, you can update your HERE Maps even easier and faster, as only those roads and other map features that have been updated will be downloaded — you don’t have to install whole countries anew.
Nokia yesterday discussed about this feature on their official blog. Here is an excerpt,
People love keeping their smartphones and apps up-to-date because they know they get the latest features and bug fixes. This is, of course, even more true for maps, which have to reflect changes to the world around us as quickly as possible.
All these updates can create some fatigue, which is why we decided to simplify the way you get new offline maps.
When an update is available, you don’t have to download all your maps anew, only those roads and other map features that have been updated will be downloaded.
On average, this means 85-90 per cent less data and therefore a much faster update process. If, say, you have downloaded 1.5GB of maps, you can expect updates to weigh in at roughly 216MB.
After this feature was rolled out, Nokia delivered their first incremental updates for offline map data few days back. Read about it here.