Palm, Cachemate And Os Grid Refs

[+Bill D (wwh)]

I recently went paperless, with CacheMate on a Palm. The one thing I miss from paper printouts is not having OS grid refs available. I still use (and prefer) paper maps, and it would sometimes be very useful to have the OS ref for a cache or a parking place to hand in the field.

 

Does anyone know of any easy way of achieving this with a Palm? For my own purposes the ideal would be some little Palm utility into which I could paste lat/long and get an OS conversion, but I can't find anything like this.

 

I know I can do a bulk conversion on the pc and send it to the Palm, but that's massive overkill for what I want.

[+wildlifewriter]

I can't find anything like this.

 

Me neither, and I don't think such a program (for PalmOS) exists.

 

Which is a pity, because Cachemate - by means of a plugin - does provide a format conversion, but only to UTM. A similar facililty for GB grid is unlikely to appear, mostly because as discussed in this slightly silly thread doing the thing with sufficient accuracy is non-trivial, mathematically.

 

Incidentally: I discovered by accident that Cachemate is now at ver 4.0.2 (since 10/10/04) whereas I was still using the 'old' 3.5. Mentioned here in case others aren't aware that a new (and much improved) version is available.

[+Puppy Galore]

No solution for you - I've looked myself, but we could try asking Brian Smith (the author of cachemate).

 

He's just finished writing me a fabulous little plugin that exports points into PathAway, which he achieved in about two days flat (what a marvellous chap!), so he may well be able to covert his UTM plugin to do OSGB grid references - especially is anyone here could actually provide him with the formulae.

 

As for the non-trivial nature of the problem.... That is more of an issue when you are trying to convert the 1-a-second data stream from a GPS for immediate display than when you are trying to do a one-off conversion of a single set of coords, and taking several seconds isn't a problem.

 

For that matter, if anyone can point me at a reasonable reference for the formulae involved, I'll give it a go at writing a Palm app myself (I've done it once or twice before...)

[+wildlifewriter]

For that matter, if anyone can point me at a reasonable reference for the formulae involved, I'll give it a go at writing a Palm app myself (I've done it once or twice before...)

There's an interesting set of routines HERE in C+ with VB hooks, which gives an idea of what's involved.

 

I don't know how accurate this would be but, looking at the code, Nick is using a generalised Helmert transformation based on this document - so it should be good for 15 feet or so...

[+Puppy Galore]

There's an interesting set of routines HERE in C+ with VB hooks, which gives an idea of what's involved.

 

I don't know how accurate this would be but, looking at the code, Nick is using a generalised Helmert transformation based on this document - so it should be good for 15 feet or so...

C# to C - that should be convertable without too much of a headache, and I still can't find anthing other than indirect references to the OSTN02 transform, so it looks like 5m accuracy is the best we're going to get......

 

I'll take a look at it, but it may take a little while....

[+Bill D (wwh)]

Puppy Galore wrote:

so it looks like 5m accuracy is the best we're going to get......

For my purposes, i.e. finding a location on a paper map in the field, that would be absolutely fine!

 

wildlifewriter wrote:

Incidentally: I discovered by accident that Cachemate is now at ver 4.0.2 (since 10/10/04) whereas I was still using the 'old' 3.5.

Thanks for the heads-up! I only installed it two months ago, but I find I'm using 3.5.3.

[+Hard Oiler]

In fact Cachemate already comes with a UTM converter. Look in the Plugins folder that came in the zip file and you'll find UTMcoord.prc

 

This plugin allows formatting of the current record's coordinates in any

of the following formats:

 

- UTM (Universal Transverse Mercator)

- Heading/Degree/Minute/Second

- Heading/Degree/Minute (the default format for CMConvert)

- Heading/Degree

- Decimal degree

 

Oops my mistake - it's OS you want not UTM

Edited October 15, 2004 by Hard Oiler

[+wildlifewriter]

(bigsnip)

Oops my mistake - it's OS you want not UTM

 

Er...yessss...

 

Incidentally... just found out today that the published co-ordinates for the OSGB's own GPS reference stations might have been wrong!

 

(Gasps of consternation all round, shock, horror, entire foundation of civilization crumbling.. etc.etc.)

 

Well, not really. It turns out that the "error" was +/- 11 millimetres, as explained HERE

 

You gotta give them points for trying.