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Maps - cache use and duration

Discussion in 'Pro/Adv Discussion' started by Philip Stowell, Jul 13, 2016.

  1. Philip Stowell

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    How long do cached maps stay in the cache for access and future flights. I ask because I covered - while on a good Wi-Fi connection and drilling down to as much detail as possible - a few areas recently getting down to detailed views for 3 planned flights around castles 30 miles apart.
    The first flight went fine.
    The other two I had to do without maps.
    One just had the blank checkered squares
    The other was so blurry as to be useless.

    Does it destroy the cache memory if I turn off the tablet in between flights?
    I didn't turn it off between these flights on this occasion but I wonder if it affected previous attempts.
    All advice gratefully accepted
    Philip
     
  2. Philip Stowell

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    PS. I am using P3P with 9.7" Samsung S3 tablet.
     
  3. GadgetGuy

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    Best backup is to hope for cell service and Hotspot your cellphone and access it from your tablet to download the maps on the fly, or use the cell phone itself as your tablet. I haven't been able to figure out what triggers the deletion of the pre-downloaded maps cache, but it happens often enough, that you need a backup plan, like the one I just suggested.
     
  4. ferraript

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    I don't know, if there is some time limit for cache
    but there is definitely storage space limit
    that means while you are caching new areas and you are above cache limit, the oldest map tiles are being deleted
    my recommendation: after you are done with caching, close the DJI GO, turn off the wifi, start the DJI GO again and check, if you are satisfied with the stored map
     
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  5. Cyclone

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    Im sure they are deleted when you reboot/turnoff the tablet.
     
  6. GadgetGuy

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    They are not deleted in that manner. It is time based and cache size based, as opposed to power related or always requiring the app to stay open. Determining the time period of persistence, and the maximum cache size permitted is the issue.
     
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  7. Mark The Droner

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    I have the same problem. I have a tablet with no cell service. I cache my maps manually while sitting in front of my router. The cached maps work perfectly for a while. They eventually vanish suddenly and completely with no warning. It's not a power down, reboot, reset, static memory or storage memory problem. From what I can tell, the **** cache just deletes itself after about a month or so. Of course, I don't know this until I'm about to launch. So I say **** it and fly anyway. The little radar pointer deal still works at least.
     
  8. GadgetGuy

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    I changed my cell phone plan to allow for Hotspotting the phone to connect my tablet to it to, specifically deal with exactly this problem. It's still cheaper than a cellular tablet, and I was already paying for the cell phone data.
     
  9. captainmilehigh

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    I forgot all about that capability. Now when I can't get my map at the flying location I have a solution! Thanks for the tip GadgetGuy.

    I have no idea why I didn't think of that sooner. Geez....


    Sent from my iPad using PhantomPilots
     
  10. Multicoptertec

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    I believe the maps expire after 30 days, or if you clear app data.
     
  11. GadgetGuy

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    Necessity is the mother of invention! ;)
     
  12. HWCM

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    If it uses google maps, it is 30 days. Open Google maps, settings, offline areas. Cache an area and when done it will give you a 30 expiration date.
     
  13. GadgetGuy

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    How do you know which maps DJI GO is using on an iOS device? Is it Apple Maps or Google Maps?
     
  14. Multicoptertec

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    Apple maps.


    Sent from my iPad using PhantomPilots
     
  15. shockwave199

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    I've had more reliable results using the standard map first, out in the field. Often times when that loads up I then have better success when I switch over to satellite or hybrid. You can also try loading the map of your site on wifi at home and then keep the go app open- don't close out of it. Then just connect to it in the field. Hybrid tends to be more reliable that way. Good luck.
     
  16. GadgetGuy

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    Then the Google Maps cache flushing after 30 days should be irrelevant. I wonder what the time persistence is on Apple Maps caching. I discovered this evening that rebooting the iPad solved the problem of no map downloading occurring in DJI GO.
     
  17. HWCM

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  18. GadgetGuy

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    Understood, which is why it begs the question of how it works on iOS devices which do use Apple Maps.
     
  19. Detrack3

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    Hi All

    I have gigs of calibrated maps that I use in Ozi-Explorer software and it would be good if you could use your own maps within the Go app so I can see if I am over the area I like to be.

    cheers
     
  20. Philip Stowell

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    I think I forgot to thank you for that suggestion.
    It worked but drains the phone really fast
    Philip