Alistair,
I found this page really useful
http://www.movable-type.co.uk/scripts/latlong.html
HTH,
Sven
> On 5 Dec 2018, at 11:48, Sven Van Caekenberghe <s...@stfx.eu> wrote:
>
>
>
>> On 5 Dec 2018, at 08:23, Alistair Grant <akgrant0...@gmail.com> wrote:
>>
>> Hi Sven,
>>
>> On Tue, 4 Dec 2018 at 11:04, Sven Van Caekenberghe <s...@stfx.eu> wrote:
>>>
>>> Hi Alistair,
>>>
>>>> On 4 Dec 2018, at 10:21, Alistair Grant <akgrant0...@gmail.com> wrote:
>>>>
>>>> Hi,
>>>>
>>>> Does anyone know of a library for processing GPS coordinates?
>>>>
>>>> What I'm looking for are things like:
>>>>
>>>> - Parsing from and printing to various string formats (HMS, NESW, decimal)
>>>> - Distance between two points
>>>> - etc.
>>>>
>>>> Thanks,
>>>> Alistair
>>>
>>> We've got some elementary stuff based on WGS84 coordinates as points. For
>>> example,
>>>
>>> T3GeoTools distanceBetween: 5.33732@50.926 and: 5.49705@50.82733.
>>> T3GeoTools bearingFrom: 5.33732@50.926 to: 5.49705@50.82733.
>>> T3GeoTools destinationFrom: 5.33732@50.926 bearing: 45 distance: 2500.
>>> T3GeoTools centroidOf: { 5.48230@50.82249. 5.49523@50.81288.
>>> 5.50138@50.82008. 5.50228@50.82595. 5.49265@50.82560. 5.48230@50.82249 }.
>>> T3GeoTools is: 5.33732@50.92601 inside: { 5.48230@50.82249.
>>> 5.49523@50.81288. 5.50138@50.82008. 5.50228@50.82595. 5.49265@50.82560.
>>> 5.48230@50.82249 }.
>>>
>>> This is not open source, but it is not rocket science either (just
>>> implementations of public algorithms).
>>
>> Right, I'll probably have a go at this a put it up on github.
>>
>> It looks like you've chosen to model the coordinates using the Point
>> class rather than creating a Coordinate class. Can you explain why (I
>> don't have a strong preference either way, so am wondering what your
>> thinking is).
>>
>> It also looks like it is longitude @ latitude. Is that correct? (I
>> guess it lines up with the point y value being vertical, which is
>> latitude. But most written forms put latitude first).
>
> I used the simplest thing that could work, using the mathematically oriented
> x@y (long@lat) form. From what I am doing, it works just fine. Converting
> to/from HMS notation is not hard I.
>
> Here is an example:
>
> distanceBetween: firstPosition and: secondPosition
> "T3GeoTools distanceBetween: 5.33732@50.926 and: 5.49705@50.82733"
>
> | c |
> c := (firstPosition y degreeSin * secondPosition y degreeSin)
> + (firstPosition y degreeCos * secondPosition y degreeCos
> * (secondPosition x degreesToRadians - firstPosition x
> degreesToRadians) cos).
> c := c >= 0 ifTrue: [ 1 min: c ] ifFalse: [ -1 max: c ].
> ^ c arcCos * 6371000
>
> I would not have anything against a real object, as long as it is
> mathematically sound and used properly. I think that only WGS84 makes sense
> as internal representation though - it seems the most common thing anyway.
>
>> Thanks!
>> Alistair
