Entering Coordinates

[whoobub]

Great app, definitely my favourite and one I use frequently for recording and logging trigpoints and benchmarks.

I usually create a log before I go out and update it when at the point of interest with the GPS position.

When creating the log I would like to be able to enter the coordinates in OS format, for example SU 33582 43491. Would this be possible in a future update?

I have been using an app called OS Convert but it does not seem to be as accurate as I would like even when entering a 10 digit OS position such as the one above and converting it to decimal cordinates. I'd welcome your thoughts on this as well.

Thanks again for a really good app and keep up the good work.

Regards...


Martin

[divzero]

Hi Martin,

More than happy to look into anything that can make GPS Log more useful! I had not heard of this system before, is it primarily used in Britain?

I think I can add a feature to allow input of OS notation. Am I right in thinking you still want it to display the lat/lng degrees in the log entry?

Kind Regards,
Will

[whoobub]

I think the display of coordinates should remain as it is, its a universally accepted format.

There are other formats, such as the OS method, and it could be good to have the option to use them.


Regards...


Martin

[divzero]

Hi Martin,

I will add this for you.

Would you be able to give me a few example OS Coords with the correct (i.e. accurate) lat/lng counterparts so I can test the conversion?

Are there any other coordinate systems that are needed? I already have Degrees, Minutes, Seconds.

Will

[whoobub]

Try this one:

SU 50410 29420

51 degrees 3 minutes 41 seconds N, 1 degree 16 minutes 50 seconds W

51.061368, -1.280575

I believe there are other formats but these are the main three.

Regards...

Martin

[divzero]

Hi Martin,

OK I have added the conversion for you.

Looks like I am using the same code as whatever code generated the test value you showed me as I get it exactly.

But there is a problem. I believe the conversion (and I guess the one you did) is in OSGB36. Google Maps uses WGS84, so I will need to do a further conversion.

If you are interested, I can provide you an early beta build of GPS Log so you can test this feature before it goes live. Just give me your UDID using this tool: http://gpslog.cc/udid

I will see if there is a way to convert to WGS84 now…

Regards,

Will

[divzero]

OK, it's done.

Input: SU 50410 29420
OSGB36 Result: 51.061368 -1.280575
WGS84 Result: 51.061912 -1.282033

Which is verified by this site.

The WGS84 result is what is used in GPS Log. As that is the datum Google Maps & the iPhone uses.


It should be noted that inputting OSGB36 coords into directly GPS Log (any version) will result in inaccuracies, as GPS Log assumes WGS84.

I am thinking of adding some if you suffix OSGB36 to a coord , e.g. "OSGB36: 51.061368 -1.280575" it will convert it correctly. Could abbreviate to "OS: ". Any thoughts?

Marvin: as mentioned, I can get you an early build to try this out if you are interested.


This was not a trivial feature to add in the end. Perhaps you will consider writing a review of GPS Log for the UK App Store when the feature goes live?

Cheers,
Will

[whoobub]

Will...

Thanks for your efforts, as soon as the update is released I will write a review on itunes.

I've added the UDID app, where do I send the number to?

Regards...


Martin

[whoobub]

I am thinking of adding some if you suffix OSGB36 to a coord , e.g. "OSGB36: 51.061368 -1.280575" it will convert it correctly. Could abbreviate to "OS: ". Any thoughts?

That sounds like a good idea.

I think you're leading the way in this field of apps!


Martin

[divzero]

Thanks for your efforts, as soon as the update is released I will write a review on itunes.

Thank you.

I've added the UDID app, where do I send the number to?

support (at) gpslogapp.com

[divzero]

I am thinking of adding some if you suffix OSGB36 to a coord , e.g. "OSGB36: 51.061368 -1.280575" it will convert it correctly. Could abbreviate to "OS: ". Any thoughts?

That sounds like a good idea.

I think you're leading the way in this field of apps!

I'm happy to hear that!, as this is my goal. GPS Log was quite unique when it launched back in Feb 2009, and I am determined to keep improving it to make it the best it can be.


In implementing this feature, I really got the impression that in Britain you don't use lat,lng coords much (and maybe even if you do, they are on OSGB36). Is that true?

I am more than willing to add an option to display in OS notation (only for valid coords in Britain) if there is a need.

Would you be interested in a free stand-alone conversion app (that was accurate)?

Kind Regards,
Will

[whoobub]

The OS system is used by the Ordnance Survey in its paper maps.

Its typical of us Brits to be a bit awkward!

We do use latitude and longitude of course.

Martin

[whoobub]

Will wrote...

Would you be interested in a free stand-alone conversion app (that was accurate)?

I would be very interested! I do have a couple of apps that are supposed to do the job but have never been convinced of their accuracy.


Martin

[divzero]

Hey,

Well I'm glad to hear that, because I made one this week! I also noticed after investigating the OS system that some of the tools out there were sub-par. Since (it seems) I got my conversion working, I figured I may as well make one. I plan to give it away for free, and use it as a bit of a promotional tool for GPS Log.

I'll get you builds of both GPS Log and this app shortly.

Regards,
Will

[divzero]

Hi Martin,

You can download the pre-release builds here: viewtopic.php?f=27&t=942&start=0

Please let me know if you have issues installing or using.

Cheers,
Will