ELR map on iPhone

Mike F (Hastings Line)

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Apr 26, 2024, 2:51:21 AMApr 26

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As the network-rail-gis-main helpfully includes polyline coordinates for ELRs, I thought I'd plot them on an iPhone app - the app can tell you which ELRs you are travelling over on a rail journey

I've put "ELRs`' on the Apple App Store as a free app - https://apps.apple.com/app/elrs/id6499340972

Also added stations and departure boards from open data

A caveat is that the algorithm that generated the ELR coordinates seems to occasionally add spurious additional points at the end of a rail line. I've tided a few up in the app's SQLite database as I've noticed them

Any feedback is welcome. I hope that the acknowledgements and open source licence links that I have included in the app cover how the open data is used

Mike

Dave Burbridge

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Apr 26, 2024, 4:50:04 AMApr 26

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Hi Mike,

I've just installed it. When starting the app, all I get is a screen flicker and then back to the background, i.e. it appears to crash on startup.

I'm on IOS 16.7.1

Regards,

Dave

Mike F (Hastings Line)

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Apr 26, 2024, 4:54:51 AMApr 26

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Cheers Dave - what model Phone are you using? Let me see if I can recreate that.

It would be useful to know how much RAM your phone has. I've had to do some degree of memory management as there are 275,000 coordinates in the ELR dataset

Mike

Dave Burbridge

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Apr 26, 2024, 6:29:01 AMApr 26

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It's an IPhone SE (model MHGB3P/A - no idea how much RAM it's got though!)

To be honest, it does struggle on some high memory apps, so it could well be that that's the problem.

D

Mike F (Hastings Line)

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Apr 26, 2024, 10:03:57 AMApr 26

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Hi Dave - after doing a few tests, the ELRs app should work if you can upgrade your SE 2 to iOS 17.2 (I know, upgrades aren't always easy when you're short on space)

I'll upload a new version of the app that does a version check on launch

Not to bore anyone with the reasons (hopefully), but the SQLite database engine on iOS does not have an in-built acos function that is used to calculate great circle distances between locations, so SQLite is configured to use the acos function from the underlying operating system core, which is confusingly called Darwin. That seems to require a more recent version of iOS. I'll see whether I can find a workaround...

Mike

Mike F (Hastings Line)

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Apr 28, 2024, 11:48:46 AMApr 28

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A version of the ELRs app is now in the App Store that works with iOS 16 upwards. Sorry for the inconvenience

Mike

Dave Burbridge

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Apr 30, 2024, 5:14:36 AMApr 30

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Hi Mike,

That works now, thanks!

Regards,

Dave

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