stale downloaded tiles aren't replaced by newer ones when online

caver456's Avatar


30 May, 2021 09:29 PM

Hi - a team member pointed out that they had a difference in mapbuilder topo trail objects between what they saw on their app and what they saw on their computer. Turns out they had a stale downloaded tile (from a year back or so), and the openstreetmap data in that area has much more data now than it did when they downloaded it. Makes sense. However - even when the phone had good cell service, the phone was still adhering to the search pattern of 1) downloaded 2) cached 3) online if available. Is there a way to modify the search pattern so that downloaded tiles will automatically be replaced with newer ones when internet is available? Data usage issues ensue... or maybe present the user with a popup / badge that says that a newer tile is available for this area, recommending that the user redo their download? what's your take on this question? Thanks!

  1. Support Staff 1 Posted by Julie on 31 May, 2021 04:31 PM

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    Hi Tom,

    Right now, the device will prioritize downloaded tiles even when in full network service. Otherwise, if the device is trying to check which one is newer, especially if in poor cell service, it really slows down the load time. It used to do that and we got tons and tons of complaints.

    There's no method at this time for alerting users that there may be an updated tile - but the changes are usually small enough and infrequent enough that it shouldn't make a huge difference for the vast majority of users as to which tile set they have. We have had a bit of internal discussion about how/if to alert users that newer tiles are available, but there's no one clear answer and it hasn't sifted to to the top of the priority pile yet.


  2. Julie closed this discussion on 31 May, 2021 04:31 PM.

  3. caver456 re-opened this discussion on 31 May, 2021 04:58 PM

  4. 2 Posted by caver456 on 31 May, 2021 04:58 PM

    caver456's Avatar

    Thanks for the response, it makes complete sense. Statistically speaking,
    I was probably one of the folks who complained in the past!

  5. Support Staff 3 Posted by Julie on 31 May, 2021 05:03 PM

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  6. Julie closed this discussion on 31 May, 2021 05:03 PM.

  7. caver456 re-opened this discussion on 31 May, 2021 05:43 PM

  8. 4 Posted by caver456 on 31 May, 2021 05:43 PM

    caver456's Avatar

    Sorry but there's a part 2 - this is hopefully more objective than

    it looks like the old mbtiles file is not getting replaced when I use the
    downloader through the app to re-download it. I'm probably missing
    something obvious, but, could you take a look?

    Here's an app screenshot of mapbuilder topo, the corresponding file is
    mapbuilder_topo-39-120-11.mbtiles, the one I have is dated 8/29/2020 7:54pm
    (not sure if that was my download time or the mbt-generation time - not
    terribly important). The area I'm using as an indication of mbt age is the
    double-back a couple hundred meters NW of the crosshairs and the
    continuation E then NNE to Paradise Lk - in the 39-120-11 mbtiles file,
    this corresponds to z=15 col=5427 row=20290 - and the fact that the PCT is
    highlighted yellow.

    [image: Screenshot_20210531-101536_CalTopo[1].jpg]

    Here's the corresponding area on from just now - notice the
    current mbt has the entire trail down to Paradise deleted, and PCT is no
    longer highlighted yellow. (side note - is the PCT highlight something OSM
    does or something you do? If it's something you do, and if it was
    inadvertently removed, I did find it handy to make the PCT visually pop

    [image: image.png]

    So, in the app I used the downloader to re-download mbt for that tile. I
    did select max resolution and elevation data - the downloader said it was
    downloading three tiles which makes sense: normal res, 2m, and elev.

    [image: Screenshot_20210531-101111_CalTopo[1].jpg]

    However, after the download finished, the tile on the phone remains
    unchanged. (Actually that first app screenshot was after the download had

    Looking at the dir on the phone, sorting by file modification time - the
    dem tiles are nice and shiny new, even though they are for a different grid
    (39-120-12 - I had selected 39-120-11 as far as I could tell, and no other
    recent files are listed anyway).

    [image: image.png]

    I did confirm that if I specifically delete
    mapbuilder_topo-39-120-11.mbtiles then do the same download again, it does
    actually download and use the new file.

    This is a Samsung S9 on Verizon; all these tile files are in the standard
    app dir as far as I know:
    \Phone\Andoid\Data\\files\tiles (as mounted on Windows

  9. Support Staff 5 Posted by Julie on 31 May, 2021 05:59 PM

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    That's because the mobile tiles for download haven't been updated. We don't do that as often as we do the web version. And actually we aren't doing it at all anymore because we are moving to a different system where the tiles will be generated on demand instead of all at once on our end. This will, I believe, allow users access to more types of offline tiles as well as some other advantages. But it didn't make sense to spend the time on both development tasks, so the tile updates for mobile are somewhat delayed until we get the new process running.


  10. 6 Posted by caver456 on 31 May, 2021 06:38 PM

    caver456's Avatar

    sounds interesting - hopefully that new system works better for you and
    better for the users. Do you have any guesses on when we'd be able to
    download updated (or, on-demand-generated) tiles?

    I thought that the issue we were seeing here was slightly different: the
    new download did not appear to be overwriting the old file - like a
    permissions issue or something. But I'm not sure of that now - just
    discovered that Windows doesn't refresh the display of the tiles dir
    consistently while the phone is plugged in - probably an MTP issue. Anyway
    after unplug and replug the newly downloaded file does show up, but it
    doesn't seem to be consistent, so at the very least Windows is causing
    enough uncertainty that it's not a legit bug report any more. Thanks for
    the help!

  11. Support Staff 7 Posted by Julie on 31 May, 2021 08:36 PM

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    We really can't say timelines for things publically. We have some internal ideas of how long things will take, but the real world just throws too many kinks in to ever allow us to share timeframes until something is actually ready!

  12. Julie closed this discussion on 31 May, 2021 08:36 PM.

  13. caver456 re-opened this discussion on 31 May, 2021 10:42 PM

  14. 8 Posted by caver456 on 31 May, 2021 10:42 PM

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    sounds good. Looking forward to it. Thanks

  15. Meghan closed this discussion on 01 Jun, 2021 12:25 PM.

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