Offline maps download countries/regions instead of viewports

[Wafflewithketchup]

When preparing for a trip or when downloading a larger area, it would be very practical to download per country, making sure there are no gaps or overlap

[ellenhp]

This would be a nice thing to have. Unfortunately, map downloads with Cardinal are quite large compared to other offline maps apps. It's one of the only downsides to using MVTs and MapLibre for rendering, but it's a big one. I'm going to look into a number of things to reduce download size, including packing as much detail as possible into z12 or z13 tiles in my forked version of planetiler-openmaptiles. This should dramatically reduce download size. I would also like to explore whether the MapLibre tile specification is ready for production use, because that also reduces tile sizes and increases compressability.

Additionally, getting the boundaries for countries and regions down to the client isn't trivial. It would probably require some curation and simplification of WhosOnFirst polygons, or potentially precomputing the tile sets per-region and storing them as a roaring bitmap.

[Wafflewithketchup]

I see what you mean about the file sizes. And for day to day use this probably works fine for most people. Would it be possible to save, say a certain radius from a map point? Or having the amount of cells (or estimate) shown while scoping the map, and shown if the selected area is too big? 25 Sept 2025 01:12:06 Ellen Poe ***@***.***>:

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[Image]*ellenhp* left a comment (ellenhp/cardinal#150)[#150 (comment)] This would be a nice thing to have. Unfortunately, map downloads with Cardinal are quite large compared to other offline maps apps. It's one of the only downsides to using MVTs and MapLibre for rendering, but it's a big one. I'm going to look into a number of things to reduce download size, including packing as much detail as possible into z12 or z13 tiles in my forked version of planetiler-openmaptiles. This should dramatically reduce download size. I would also like to explore whether the MapLibre tile specification is ready for production use, because that also reduces tile sizes and increases compressability. Additionally, getting the boundaries for countries and regions down to the client isn't trivial. It would probably require some curation and simplification of WhosOnFirst polygons, or potentially precomputing the tile sets per-region and storing them as a roaring bitmap. — Reply to this email directly, view it on GitHub[#150 (comment)], or unsubscribe[https://github.com/notifications/unsubscribe-auth/AQYIMBPDKKPURNYIKTXWLA33UMQMLAVCNFSM6AAAAACHNJ7HESVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTGMZQHE4DCMZTGU]. You are receiving this because you authored the thread. [Tracking image][https://github.com/notifications/beacon/AQYIMBLRSGO6RBTL4PHXB5D3UMQMLA5CNFSM6AAAAACHNJ7HESWGG33NNVSW45C7OR4XAZNMJFZXG5LFINXW23LFNZ2KUY3PNVWWK3TUL5UWJTWGRK65O.gif]

[ellenhp]

Yes, those are both very feasible. I'm going to throw a help wanted on this issue to track those more immediate feature requests and probably open another one to investigate switching to MapLibre Vector Tiles (this will affect the offline geocoder functionality too, so it's likely to be a while before it filters to the top of the heap).

[Wafflewithketchup]

I would say I'm keen to help, but I'm both inexperienced in kotlin, and have little time. But very impressed with the responsiveness and feel of the app. 25 Sept 2025 01:38:10 Ellen Poe ***@***.***>:

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[Image]*ellenhp* left a comment (ellenhp/cardinal#150)[#150 (comment)] Yes, those are both very feasible. I'm going to throw a help wanted on this issue to track those more immediate feature requests and probably open another one to investigate switching to MapLibre Vector Tiles (this will affect the offline geocoder functionality too, so it's likely to be a while before it filters to the top of the heap). — Reply to this email directly, view it on GitHub[#150 (comment)], or unsubscribe[https://github.com/notifications/unsubscribe-auth/AQYIMBJLZUD3SI4SYTMLAET3UMTOFAVCNFSM6AAAAACHNJ7HESVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTGMZRGAZDGMZXHE]. You are receiving this because you authored the thread. [Tracking image][https://github.com/notifications/beacon/AQYIMBJPSKTEFUT6UMII32L3UMTOFA5CNFSM6AAAAACHNJ7HESWGG33NNVSW45C7OR4XAZNMJFZXG5LFINXW23LFNZ2KUY3PNVWWK3TUL5UWJTWGRNRBG.gif]