android cpn issue

[Birdseye]

had it working on an android tablet for years and then had to temporarily remove the sd card that the charts were on. Putting the sd card back in, the program now wont see the charts and indeed has got a bit odd in its zoom behaviour. Have a vague memory from way back about some procedure for loading charts but cannot remember any detail. Help!

Should add that both the cpn version and the charts are old and obsolete - not used for nav so much as day dreaming. Got an up to date plotter on the boat so not interested in paying to update the cpn or its charts. Just want to get it working again

 

[Davy_S]

Just a thought and it might not help, when you insert an SD card into a tablet you can set it as internal storage or removable storage, ie if you wanted to store photos on it so you could remove it and place it in another device to view your photos, you would set it as removable storage, but if you set it as internal storage you would not be able to do this, is it possible that this has happened to your charts?

 

[Pye_End]

Have you updated Android since your last use? There was a problem a while back with chart locations on SD card because of this, the details of which I am struggling to remember. I think in the end I moved the charts to the internal memory. There was a moving tool with one of the OpenCPN updates but I couldn't get it to work at the time.

 

[st599]

When you insert an SD card in to a Linux system (like Android) it gets given a unique name. Anything like a system update, changes to the files on the card etc. could cause a different unique name to be created.

 

[greeny]

Have you updated Android since your last use? There was a problem a while back with chart locations on SD card because of this, the details of which I am struggling to remember. I think in the end I moved the charts to the internal memory. There was a moving tool with one of the OpenCPN updates but I couldn't get it to work at the time.

Yes I remember that. Quite a while ago. Putting the charts on internal memory worked as you say, but at the time i worked out how to use them from the sd card as well. Cant remember exactly what i did, but i'll look at my system and se if i can work out what i did.

 

[greeny]

Thread 'OPEN CPN' OPEN CPN

See post 26 and 27.

 

[bluerm166]

You have maybe succumbed to an Android update which you couldn't prevent.
Apart from issuing constant updates and cluttering apps that you dont want and can't remove Google now prevents an SD card being used as true extended memory ,only for 'dead' storage.
No doubt a security issue but particularly annoying where you have limited internal memory and are up to your space limit on an otherwise capable tablet.
I have to be extremely disciplined on my 2016 Samsung tablet and use a recent tablet for other purposes.One option is to deploy an edited -down version of CM93 to free some base storage.

 

[ProDave]

I want to know how you even got Open CPN to work with charts on an SD card on Android? I never did work out how you find that in android. Instead I had to load the charts into scarce native phone memory when i would love to have had them on the plentiful SD card storage.

 

[greeny]

I want to know how you even got Open CPN to work with charts on an SD card on Android? I never did work out how you find that in android. Instead I had to load the charts into scarce native phone memory when i would love to have had them on the plentiful SD card storage.

Post 6 - read the thread, posts 26, 27 may or may not help. I managed to do it and its still working. If I can then I would say, so can most. Version of Android also appears have some say in success or not.

 

[bluerm166]

If shortage of main storage on your older tablet is the problem ,as it has been mine on a Samsung Tab A 2016 SM-T580 16GB ,Android 8.1 Samsung 9.5 used for navigation with OpenCPN mainly as a backup to Marine Navigator but also to deploy the free NL inland yearly ENC charts you will also have been frustrated by the inability to use an SD card effectively.
Following on from the posts by Birdseye,Geeny and others I have researched this again.
You might not get Open CPN to address charts held on an SD card but you can shift the app itself to the external card followed by the charts and I have got this to work using CM93 as an example.
To shift the app across use developer mode as shown simply here : Easytechs video
It was harder to get the charts into place (moving a whole folder) but using the tablet connected to PC by cable as others have recommended this becomes easy.
Remarkably it works.
Obviously you should backup anything precious before following this route.Other secondary apps could be shifted in the same way.
I haven't found this described in one place previously .How later Android versions respond to this I cannot say.

If you do use an older tablet like this and have a waning battery ( I have replaced once already) by using an Amazon basics 4.8 A 24W Dual car charger on the boat you can start and finish a long days navigation with a full charge.Its the 2.4 A per outlet that allows gain rather than depletion.

Amazon.co.uk​

I also carry a recent samsung tablet as a complete backup including apps and charts.

 

[ProDave]

Post 6 - read the thread, posts 26, 27 may or may not help. I managed to do it and its still working. If I can then I would say, so can most. Version of Android also appears have some say in success or not.

Thanks I tried that.

I could move the Open CPN app itself to the SD card but it would then not open after a phone re start, so I moved it back. Whatever else I tried would not persuade it to see the charts on the SD card, or indeed see the SD card at all in it's file open options.

However using that information I was able to move a number of other (not very important) apps to the SD card and free up some phone storage that way.

 

[bluerm166]

Interesting.Obviously circumstances differ.
I have often had difficulty getting recognition of chart files in the directory .
In this case I copied the exact directory entry from my PC where it works happily on OPEN CPN.
I recall that the address must include the last folder that contains the charts.

 

[ProDave]

the issue on my phone, is it cannot see any sign of the SD card even if i navigate to the root (../ in Android speak as many times as you can until it won't go any further)

I can see the SD card and the charts on there using the Android file manager, but the options you have withing open CPN won't allow me to navigate anything other than the native phone storage, even after trying all the tricks posted before.

 

[HunterWanderer]

I think you have to update opencon to latest verion and store charts on internal memory. Mine wont read from sd card.