Reply to: GPS for walking...

[TimberWolf]

I think they got pretty good at estimating latitude using a sextant, within a couple of miles IIRC.

The Wiki says an experienced navigator could determine position using a sextant to an accuracy of a quarter of a nautical mile

[NickFitz]

Got one of them - A miniature folding brass sextant about the size of a large pocket watch.

Looks nice in its satin lined mahogany box, but the trouble is I have no idea how to use it.

It all seems pretty straightforward

[OwlHoot]

I was thinking a little miniaturised Hornblowery thing you could put in your pocket.

Got one of them - A miniature folding brass sextant about the size of a large pocket watch.

Looks nice in its satin lined mahogany box, but the trouble is I have no idea how to use it.

[TimberWolf]

I think they got pretty good at estimating latitude using a sextant, within a couple of miles IIRC. Longitude needed a watch and/or deadreckoning.

[EternalOptimist]

I was thinking a little miniaturised Hornblowery thing you could put in your pocket.

actually, you make a blooming good point here Xoggoth. DOH - its so obvious.

Hornblower (and a gps) will tell you where you are on the globe (even if the map underneath is wrong)

A crack orienteer will tell you exactly where you are on a map (and God help you if the map is wrong)

[TimberWolf]

I was thinking a little miniaturised Hornblowery thing you could put in your pocket.

A pocket sextant? Like my avatar?

[xoggoth]

I was thinking a little miniaturised Hornblowery thing you could put in your pocket.

[EternalOptimist]

Does one need GPS? Wouldn't it be possible for a device to work out a fairly exact position from sun direction, time, compass position and declination? Like orienteering for people who can't be arsed to do it themselves.




Naturally I am looking for something exceedingly cheap. Thought that went without saying in my case.

well, historically people like Hornblower were pretty good at finding their position on the globe, but you wouldnt want to carry a big clock, chart and sextant around on your back. would you ?

for all practical purposes, you have two choices, get the gps system, or get yourself trained up as a top orienteer

[NickFitz]

Ah yes. Second time I've forgotten that point. Did a bug identification app on Android and emailed a site with lots of photos suggesting we did a link to them for those species we did not have. He said they had already paid someone a lot of dosh to look into it and gave up as nobody could get a signal out in the sticks.

Does one need GPS? Wouldn't it be possible for a device to work out a fairly exact position from sun direction, time, compass position and declination? Like orienteering for people who can't be arsed to do it themselves.

I assume he meant a mobile phone signal - if anything, a GPS receiver is likely to perform better in the countryside than in a built-up area, as it can see more of the sky.

[xoggoth]

Neither are most GPS units as they won't get a signal

Ah yes. Second time I've forgotten that point. Did a bug identification app on Android and emailed a site with lots of photos suggesting we did a link to them for those species we did not have. He said they had already paid someone a lot of dosh to look into it and gave up as nobody could get a signal out in the sticks.

Does one need GPS? Wouldn't it be possible for a device to work out a fairly exact position from sun direction, time, compass position and declination? Like orienteering for people who can't be arsed to do it themselves.

The later and more expensive GPSs

Naturally I am looking for something exceedingly cheap. Thought that went without saying in my case.

[Paddy]

Neither are most GPS units as they won't get a signal.

The later and more expensive GPSs will work fine even inside a concrete building.

[doodab]

Not much good if you run miles through dank drippy woods.

Neither are most GPS units as they won't get a signal.

[TimberWolf]

I had one of the most 'doh' moments of my life when some spotty youth in Australia explained to me a few years ago how to find North with a digital watch.

He told me to just imagine a clock face, and imagine where the hour hand would be. (The look on his face was 'jeez mate, dont they teach you poms ANYTHING in school ')

One trouble I have is remembering whether to point the hour hand or the twelve o'clock position at the sun before bisecting the angle (it's the hour hand, but I checked again just now in case). Usually an approximate direction will do me, fortunately as it isn't super accurate anyway.

[EternalOptimist]

Yeah, Australians are always getting lost.

You can use the moon too, though my memory of this is a bit flakier, specifically relating to its accuracy. I have used it though. If you contiue an imagined line of the shadow of the earth on the moon (there is probably a name for this line, but it escapes me) to the horizon, that's south, or north in the southern hemisphere. So I guess at full moon, south is directly below the moon. Course the stars would be easier to use than the moon, except for Australians again.

I had one of the most 'doh' moments of my life when some spotty youth in Australia explained to me a few years ago how to find North with a digital watch.

He told me to just imagine a clock face, and imagine where the hour hand would be. (The look on his face was 'jeez mate, dont they teach you poms ANYTHING in school ')

[Troll]

I used to do that until I found out the bastard was dishonest. I would know exactly which direction to go and it would try and fool me by shining from the North.

You should have cross referenced that with which side of a tree the moss was growing on