Todays ride (which GPS?) ...



E

elyob

Guest
I'll keep it brief. One argument, two near collisions with cars pulling out
in front, one p*nct*re, no pump, friends GPS.

Good news is that my puncture happened about 10 metres from a bike shop. I
asked if I could buy a tube, thinking that he'd lend me a decent pump. The
one he tried to sell me came in a box about the size of a brick. I decided
that I might give it a miss. Got a crappy old hand pump, but better than
nothing. Didn't have enough cash to buy a decent one. Tiny bit of glass had
hidden itself in the rubber of the tyre. Glad I checked properly otherwise
I'd have punctured 2 miles later....

Rain was about, with one massive downpour when I was stood under a shop
canopy. Phew!

Took loads of photos of businesses for a website I'm doing. (Hence the
stopping and cycling about lost in Croydon and Sutton etc).

My friends GPS worked well. I've now got a good track of what my cycle was
like via Google maps. Pretty cool.
http://fishpluschips.com/GPS/croydon.php

I'm now seriously considering a GPS system for myself. There's no point
buying a bracket for his one to attach to my my handlebars if I have to
return it soon. After using my friends Magellan GPS315 I've now got some
requirements for one I want to buy. Rechargeable, but I guess buying
rechargeable batteries is a decent enough compromise. Smaller than the
Magellan ideally. Maps are not neccesary. What is missing from this current
one (it may be the gpsu software), is the saving of bearing when saving
trackpoints. A little annoying as I could improve the google maps website by
putting arrows showing my route.

Any suggestions?

Thanks

Nick
 
K

Keith Willoughby

Guest
"elyob" <[email protected]> writes:

> My friends GPS worked well. I've now got a good track of what my cycle was
> like via Google maps. Pretty cool.
> http://fishpluschips.com/GPS/croydon.php


Brilliant! Is that automated?

> I'm now seriously considering a GPS system for myself.


If I could effortlessly do what you've done there, I'd seriously
consider it myself, too. I'd love to map the Taff Trail.

--
Keith Willoughby http://flat222.org/keith/
Fair and balanced
 
I

Ian Smith

Guest
On Sat, 30 Jul 2005 19:21:13 +0100, elyob <[email protected]> wrote:

> Magellan ideally. Maps are not neccesary. What is missing from this current
> one (it may be the gpsu software), is the saving of bearing when saving
> trackpoints. A little annoying as I could improve the google maps website by
> putting arrows showing my route.
>
> Any suggestions?


Very few of them actually know bearing (there are a few with compass
built in, but it's generally a very poor compass). It only knows
bearing because it knows where the last point is and where this point
is, so you can always work out the bearing from the tracklog as well
as the unit could (and indeed did in the first place).

regards, Ian SMith
--
|\ /| no .sig
|o o|
|/ \|
 
J

Jeremy Parker

Guest
"elyob" <[email protected]> wrote

[snip]

>
> I'm now seriously considering a GPS system for myself.


[snip]

So am I.

There's something called a Garmin Forerunner about which there's a
thread going in rec.bicycles.misc. The title of the thread is
something to do with commuting, because everyone is posting beautiful
maps of their commutes.

As far as I can tell, you only get the pretty maps by subscribing to
some web service, at vast monthly expense, which raises the question
of whether the Forefunner puts out its data in some special
proprietary format, rather than something generic. Come to that,
what kind of plug is on the cable. And will it do maps outside the
USA, even if one does pay a subscription

The Forerunner is worn like a wristwatch. The expensive model is a
combined GPS and pulse monitor, so you can correlate your pulse with
speed and elevation gain - neat.

Other questions I have with the Forerunner is whether it can cope
with things like the UK national grid, and non US geoids that
actually make the Greenwich Meridian go through the Greenwich
Observatory.

Jeremy Parker
 
E

elyob

Guest
"Keith Willoughby" <[email protected]> wrote in message
news:[email protected]
> "elyob" <[email protected]> writes:
>
>> My friends GPS worked well. I've now got a good track of what my cycle
>> was
>> like via Google maps. Pretty cool.
>> http://fishpluschips.com/GPS/croydon.php

>
> Brilliant! Is that automated?
>
>> I'm now seriously considering a GPS system for myself.

>
> If I could effortlessly do what you've done there, I'd seriously
> consider it myself, too. I'd love to map the Taff Trail.


I used the Google API, you're happy to the source. You need a PHP enabled
server. I'm looking at building a site so others can upload their data.
Would you pay for it?! :)
 
E

elyob

Guest
"Ian Smith" <[email protected]> wrote in message
news:[email protected]
> On Sat, 30 Jul 2005 19:21:13 +0100, elyob <[email protected]> wrote:
>
>> Magellan ideally. Maps are not neccesary. What is missing from this
>> current
>> one (it may be the gpsu software), is the saving of bearing when saving
>> trackpoints. A little annoying as I could improve the google maps
>> website by
>> putting arrows showing my route.
>>
>> Any suggestions?

>
> Very few of them actually know bearing (there are a few with compass
> built in, but it's generally a very poor compass). It only knows
> bearing because it knows where the last point is and where this point
> is, so you can always work out the bearing from the tracklog as well
> as the unit could (and indeed did in the first place).
>
> regards, Ian SMith


I figured that out after I posted. If you know where you were before, then
you can work out the direction when you hit your new point. I liked the
Carol part of Countdown, and my maths is okay. But not rocket science maths.

How can I work out the angle between these?

#1 ( -0.2952833333333333 51.385083333333334 )
#2 ( -0.2843333333333333 51.38218333333333 )

or

#1 ("N51°23.1050' W000°17.7170' ")
#2 ("N51°22.9310' W000°17.0600' ")


Thanks
 
K

Keith Willoughby

Guest
"elyob" <[email protected]> writes:

> "Keith Willoughby" <[email protected]> wrote in message
> news:[email protected]
>> "elyob" <[email protected]> writes:
>>
>>> My friends GPS worked well. I've now got a good track of what my cycle
>>> was
>>> like via Google maps. Pretty cool.
>>> http://fishpluschips.com/GPS/croydon.php

>>
>> Brilliant! Is that automated?
>>
>>> I'm now seriously considering a GPS system for myself.

>>
>> If I could effortlessly do what you've done there, I'd seriously
>> consider it myself, too. I'd love to map the Taff Trail.

>
> I used the Google API, you're happy to the source. You need a PHP enabled
> server.


PHP is not a problem. I'd be most interested.

I was actually looking at this the other day, with the intentions of
doing it manually, but came to the conclusion that cycling the Trail
would be much easier than trying to come up with the way-points from the
map.

So, you just upload a set of waypoints?

> I'm looking at building a site so others can upload their data.


Neat idea. Someone mentioned last year that they were doing something
similar, but he was generating maps. I think using the Google API
produces a much nicer experience.

> Would you pay for it?! :)


Nope. And Google wouldn't be too happy, either :) (Check the T&Cs)

--
Keith Willoughby http://flat222.org/keith/
"Taffy was a Welshman, Taffy was a thief"
 
E

elyob

Guest
"David Nutter" <[email protected]> wrote in message
news:[email protected]
> On 2005-07-30, elyob <[email protected]> wrote:
>
>> My friends GPS worked well. I've now got a good track of what my cycle
>> was
>> like via Google maps. Pretty cool.
>> http://fishpluschips.com/GPS/croydon.php

>
> That is marvellous.
>



Thanks .. It's version 0.1a at the moment ... can't wait to improve it and
also own my own GPS computer one day!

I want to put arrows on it next. Just trying to figure the mathematice
behind lat/long bearings. Well, not now. I'm drinking a beer and half
watching a film.

Also wondering where my next journey is.

In the mean time, check out ...

http://fishpluschips.com/GPS/london.php
and
http://fishpluschips.com/GPS/hello.php (my quick evening sprint)
 
E

elyob

Guest
"Keith Willoughby" <[email protected]> wrote in message
news:[email protected]
> "elyob" <[email protected]> writes:
>
>> "Keith Willoughby" <[email protected]> wrote in message
>> news:[email protected]
>>> "elyob" <[email protected]> writes:
>>>
>>>> My friends GPS worked well. I've now got a good track of what my cycle
>>>> was
>>>> like via Google maps. Pretty cool.
>>>> http://fishpluschips.com/GPS/croydon.php
>>>
>>> Brilliant! Is that automated?
>>>
>>>> I'm now seriously considering a GPS system for myself.
>>>
>>> If I could effortlessly do what you've done there, I'd seriously
>>> consider it myself, too. I'd love to map the Taff Trail.

>>
>> I used the Google API, you're happy to the source. You need a PHP enabled
>> server.

>
> PHP is not a problem. I'd be most interested.


(email me for more info)

> I was actually looking at this the other day, with the intentions of
> doing it manually, but came to the conclusion that cycling the Trail
> would be much easier than trying to come up with the way-points from the
> map.
>
> So, you just upload a set of waypoints?
>


I use gpsu to get the info from the GPS, then I parse that data and get what
I'm interested in. Trying to figure out their XML method as javascript is
far too restrictive. I'd also like to have hover over rather than click
pins.

>> I'm looking at building a site so others can upload their data.

>
> Neat idea. Someone mentioned last year that they were doing something
> similar, but he was generating maps. I think using the Google API
> produces a much nicer experience.
>
>> Would you pay for it?! :)

>
> Nope. And Google wouldn't be too happy, either :) (Check the T&Cs)


sshh .. I know :)

It'd be a free to use site, but using adsense etc ..
 
E

elyob

Guest
"elyob" <[email protected]> wrote in message
news:[email protected]
>
> "Ian Smith" <[email protected]> wrote in message
> news:[email protected]
>> On Sat, 30 Jul 2005 19:21:13 +0100, elyob <[email protected]> wrote:
>>
>>> Magellan ideally. Maps are not neccesary. What is missing from this
>>> current
>>> one (it may be the gpsu software), is the saving of bearing when saving
>>> trackpoints. A little annoying as I could improve the google maps
>>> website by
>>> putting arrows showing my route.
>>>
>>> Any suggestions?

>>
>> Very few of them actually know bearing (there are a few with compass
>> built in, but it's generally a very poor compass). It only knows
>> bearing because it knows where the last point is and where this point
>> is, so you can always work out the bearing from the tracklog as well
>> as the unit could (and indeed did in the first place).
>>
>> regards, Ian SMith

>
> I figured that out after I posted. If you know where you were before, then
> you can work out the direction when you hit your new point. I liked the
> Carol part of Countdown, and my maths is okay. But not rocket science
> maths.
>
> How can I work out the angle between these?
>
> #1 ( -0.2952833333333333 51.385083333333334 )
> #2 ( -0.2843333333333333 51.38218333333333 )
>
> or
>
> #1 ("N51°23.1050' W000°17.7170' ")
> #2 ("N51°22.9310' W000°17.0600' ")
>
>
> Thanks



Looks like I need a maths lesson pretty sharpish ..

http://www.movable-type.co.uk/scripts/LatLong.html
 
K

Keith Willoughby

Guest
"elyob" <[email protected]> writes:

> "Keith Willoughby" <[email protected]> wrote in message
> news:[email protected]
>>
>> PHP is not a problem. I'd be most interested.

>
> (email me for more info)


Done. (I hope that's your valid email address ;-))

>>
>> So, you just upload a set of waypoints?
>>

>
> I use gpsu to get the info from the GPS, then I parse that data and get what
> I'm interested in. Trying to figure out their XML method as javascript is
> far too restrictive. I'd also like to have hover over rather than click
> pins.


It'd be neat if version 0.5 also allowed you to insert photos into the
pin popup . . . :)

--
Keith Willoughby http://flat222.org/keith/
I have seen the enemy, and he is quite short.
 
E

elyob

Guest
"Keith Willoughby" <[email protected]> wrote in message
news:[email protected]
> "elyob" <[email protected]> writes:
>
>> "Keith Willoughby" <[email protected]> wrote in message
>> news:[email protected]
>>>
>>> PHP is not a problem. I'd be most interested.

>>
>> (email me for more info)

>
> Done. (I hope that's your valid email address ;-))
>
>>>
>>> So, you just upload a set of waypoints?
>>>

>>
>> I use gpsu to get the info from the GPS, then I parse that data and get
>> what
>> I'm interested in. Trying to figure out their XML method as javascript is
>> far too restrictive. I'd also like to have hover over rather than click
>> pins.

>
> It'd be neat if version 0.5 also allowed you to insert photos into the
> pin popup . . . :)


Responded to your email!

As you mention it, part of my project is to take photos. So, yes, this is
something I'm interested in. But I think I'll use the mobile phone timestamp
with the gps timestamp and give me a approximate location. Version 11 may
include using bluetooth .. but I've almost finished my beer and need to get
another. And not happy with the complexity of "The haversine formula".

:)
 
E

elyob

Guest
"Keith Willoughby" <[email protected]> wrote in message
news:[email protected]

> I was actually looking at this the other day, with the intentions of
> doing it manually, but came to the conclusion that cycling the Trail
> would be much easier than trying to come up with the way-points from the
> map.
>
> So, you just upload a set of waypoints?


Well, no .. this is just following my route. But I have been looking at
creating waypoints using google maps. I'm hoping to create a waypoint
creator using google maps.

It's at version -0.1 at the moment.

http://fishpluschips.com/GPS/create.php

But it sure looks like a possibility.

Want to help build it? I really think the XML API is a better bet than
javascript ..
 
K

Keith Willoughby

Guest
"elyob" <[email protected]> writes:

> It's at version -0.1 at the moment.
>
> http://fishpluschips.com/GPS/create.php
>
> But it sure looks like a possibility.
>
> Want to help build it? I really think the XML API is a better bet than
> javascript ..


Sure. Like I said, I was looking at the API the other week, and was
planning on doing something with it. I've been looking out on ebay for a
GPS device, too, but I've not seen anything that suits my
cheapskatedness yet :)

--
Keith Willoughby http://flat222.org/keith/
"Everything is broken"
 
E

elyob

Guest
"Keith Willoughby" <[email protected]> wrote in message
news:[email protected]
> "elyob" <[email protected]> writes:
>
>> It's at version -0.1 at the moment.
>>
>> http://fishpluschips.com/GPS/create.php
>>
>> But it sure looks like a possibility.
>>
>> Want to help build it? I really think the XML API is a better bet than
>> javascript ..

>
> Sure. Like I said, I was looking at the API the other week, and was
> planning on doing something with it. I've been looking out on ebay for a
> GPS device, too, but I've not seen anything that suits my
> cheapskatedness yet :)


I'm not far off figuring up the upload stuff. Just working on prettying up
the download stuff. However I still also need to read the GPS manual to
figure out what the machine can do! From what I can tell, it's pretty funky
and I'm on the hunt for a GPS bracket for my handlebars.

The most important thing I learnt today was that GPS allows me to take
completely different (new) routes rather than stick to what my ex-"car
owning brain" tells me.

Ebay reckons you can pick up a GPS315 for about £50. That's a good price for
what it does. (i.e. gives me more of an instinct to hunt new routes .. if I
don't like a min road I can now turn off and just follow a new, made up,
route.)

The create google maps thing is pretty close to cracking the nut. I won't be
working on it tonight, and am thinking of getting up early tomorrow and
getting a train to Southampton and trialling my GPS there tomorrow. The
weather looks fair tomorrow. That's my last beer for tonight though, and I'm
yawning. Goodnight!
 
I

Ian Smith

Guest
On Sat, 30 Jul 2005 23:53:25 +0100, elyob <[email protected]> wrote:
>
> "Ian Smith" <[email protected]> wrote in message
> news:[email protected]
> >
> > Very few of them actually know bearing (there are a few with compass
> > built in, but it's generally a very poor compass). It only knows
> > bearing because it knows where the last point is and where this point
> > is, so you can always work out the bearing from the tracklog as well
> > as the unit could (and indeed did in the first place).

>
> I figured that out after I posted. If you know where you were before, then
> you can work out the direction when you hit your new point. I liked the
> Carol part of Countdown, and my maths is okay. But not rocket science maths.
>
> How can I work out the angle between these?
>
> #1 ( -0.2952833333333333 51.385083333333334 )
> #2 ( -0.2843333333333333 51.38218333333333 )
>
> or
>
> #1 ("N5123.1050' W00017.7170' ")
> #2 ("N5122.9310' W00017.0600' ")



OK, whistle-stop tour. Bear in mind this is my understanding as
'interested amateur' rather than actual professional expert. The
difficult part is going from GPS lat-long (which is based on WGS84
datum) to a flat paper map grid (which, if OS, is based on OSGB36
datum).

It can't be done precisely, but there are about 3 levels of 'close
enough' that can be done.

It can't be done precisely because the grid system you're wanting the
bearing in does not consistently mathematically map onto any lat-long
system, because of the way it is defined. This is the consequence of
historical differences in surveys.

You can pay the OS lots of cash and get a very complicated transform
that will give you millimetre accuracy. This is called OSTN97 and
something else I forget. You don't want it.

You can use a 6-parameter iterative calculation that will give you
metre accuracy transformation between the lat-long spewed by the GPS
to lat-long used by OS, and can then transform that by transverse
mercator to a theoretical grid. This will give you metre accuracy.
This is what I used in my program for the Psion 5mx which you can find
at http://www.astounding.org.uk/ian/GPSion5/ . You probably don't
want this either for your application.

You can pretend the earth is a sphere, and ignore any spherical
geometry effects, thus avoiding the need for eg transverse mercator.
For simply slapping an arrow on a map, you probably want this one.

If your data is in magellan standard format '5123.1050' means 51
degrees 23.1050 minutes.

Note that 1 degree of latitude is the same length (on our spherical
earth) everywhere on the surface, so we just note that from #1 to #2
you went 22.9310-23.1050 = -0.174 minutes north.

1 degree of longitude varies in length depending on your latitude.
At latitude 'x', 1 degree longitude is cos(x) times as long as at the
equator. You travelled 17.0600-17.7170 = -0.656 minutes west, or
0.656 minutes east. But, because you did so at 51.383 degrees north
that's only as far over the ground as 0.656 x cos(51.383) = 0.656 x
0.624 = 0.409 minutes east at the equator.

One minute of latitude, or one minute of equatorial longitude, is 1
nautical mile (which is handy). So, you went -0.174 n.mile north,
and 0.409 n.mile east. By simple trig, that means a bearing of
90+asin(0.174/0.409) = 115 degrees. This will be closeish, as long as
your two points are fairly close together (less than a degree will be
fine, I think).

Note that the lat/long used by OS is up to a few hundred metres away
from the lat/long used by GPS, but that doesn't much upset this calc.
Also, the world is not spherical, as assumed here. Also, having
assumed it's spherical to get the distances over the ground, I've
immediately assumed it's flat to get the bearing.

If you want to do any of this seriously you really need the iterative
calc referred to above (it's a 'helmert transformation') and then do
transverse mercator projection properly. If that interests you, I'd
recommend obtaining (it used to be a free download) 'a guide to
coordinate systems in Great Britain' from the OS. It's a 40 page
booklet that describes all about datums, transforms and so on, and
includes a worked example of the 'proper' helmert and TM
transformations to go from GPS values to OS grid values. It's quite
interesting, if you like that sort of thing.

regards, Ian SMith
--
|\ /| no .sig
|o o|
|/ \|
 
I

Ian Smith

Guest
On Sun, 31 Jul 2005 01:35:02 +0100, elyob <[email protected]> wrote:
>
> Ebay reckons you can pick up a GPS315 for about 50. That's a good price for
> what it does. (i.e. gives me more of an instinct to hunt new routes .. if I
> don't like a min road I can now turn off and just follow a new, made up,
> route.)


I use a 315. It's a good basic unit, in my opinion.

Magellan used to have a document "Data Transmission Protocol
Specification for Magellan Products" on their web site. Unfortunately
it had disappeared last time I looked, and it never described the 'high
speed protocol' anyway.

If you get into programming the transmission yourself, bear in mind
the protocol varies across units - the 315 protocol includes for 6
character waypoint names, but some units use 8 characters, that sort
of thing.

regards, Ian SMith
--
|\ /| no .sig
|o o|
|/ \|
 
E

elyob

Guest
"Ian Smith" <[email protected]> wrote in message
news:[email protected]
> On Sun, 31 Jul 2005 01:35:02 +0100, elyob <[email protected]> wrote:
>>
>> Ebay reckons you can pick up a GPS315 for about 50. That's a good price
>> for
>> what it does. (i.e. gives me more of an instinct to hunt new routes ..
>> if I
>> don't like a min road I can now turn off and just follow a new, made up,
>> route.)

>
> I use a 315. It's a good basic unit, in my opinion.
>
> Magellan used to have a document "Data Transmission Protocol
> Specification for Magellan Products" on their web site. Unfortunately
> it had disappeared last time I looked, and it never described the 'high
> speed protocol' anyway.
>
> If you get into programming the transmission yourself, bear in mind
> the protocol varies across units - the 315 protocol includes for 6
> character waypoint names, but some units use 8 characters, that sort
> of thing.
>



My head hurts ....

Thanks .. am trying this out and am writing a script to do the hard work!
 
S

Simon Brooke

Guest
in message <[email protected]>, elyob
('[email protected]') wrote:

>
> "Ian Smith" <[email protected]> wrote in message
> news:[email protected]
>> On Sat, 30 Jul 2005 19:21:13 +0100, elyob <[email protected]>
>> wrote:
>>
>>> Magellan ideally. Maps are not neccesary. What is missing from this
>>> current
>>> one (it may be the gpsu software), is the saving of bearing when
>>> saving trackpoints. A little annoying as I could improve the google
>>> maps
>>> website by
>>> putting arrows showing my route.
>>>
>>> Any suggestions?

>>
>> Very few of them actually know bearing (there are a few with compass
>> built in, but it's generally a very poor compass). It only knows
>> bearing because it knows where the last point is and where this point
>> is, so you can always work out the bearing from the tracklog as well
>> as the unit could (and indeed did in the first place).
>>
>> regards, Ian SMith

>
> I figured that out after I posted. If you know where you were before,
> then you can work out the direction when you hit your new point. I
> liked the Carol part of Countdown, and my maths is okay. But not rocket
> science maths.
>
> How can I work out the angle between these?
>
> #1 ( -0.2952833333333333 51.385083333333334 )
> #2 ( -0.2843333333333333 51.38218333333333 )


You think you've got problems? I've got a lot of data in OSGrid format
that needs to be plotted onto Google maps, to I have to do the
conversion to latitude/longitude. So I've got to recast this lot
<URL:http://www.gps.gov.uk/guideB.pdf> into Java. The really frustrating
thing is that at one point I had it working, and I've reintroduced a
bug. I /think/ I've got the working version in the CVS... I really hope
so. But I'm having to go back through a lot of changes to check.

--
[email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/

to err is human, to lisp divine
;; attributed to Kim Philby, oddly enough.