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Posted: Sat Jan 05, 2008 10:44 pm Post subject: Active 10 Altitude reading
I have read the comments on this forum for the past couple of months and on balance decided to buy one( Christmas obviously!).
I won't replay the pros and cons as they have been covered very well in all the postings to date.
I have used it a couple of times to get used to it and it feels very good and fairly intiuative. I have never had a GPS before so I don't have the problems with comparing it to the competition, and I get lost in some of the more detailed discussions.
It feels right and the OS mapping is something that is important to me, so the reason for the purchase.
I have however just set a route for a hillwalk tomorrow and the SATMAP altitude readings on the planned route are suspect. The top waypoint on the satmap is 40 metres lower than the OS map. I have toggled to the max magnification and still cannot get it anywhere close to the official reading. By official I mean straight from the paper OS 25,000 map and also using a downloaded Anquet 25,000 map with the same grid co-ordinates as the Satmap.
Anyone else come accross this?
I'll post again when I get back from the walk, weather permitting, to see if the satmap altimeter is Ok on the day. I use a Suunto altimeter, and have done so for 10 years, so I am fairly confident about the readings I will compare the satmap to.
Just a final note I think that the contributions on the Pocket GPS Forums re Satmap have been the most constructive and balanced about any new product that has gone through a recent product launch, and I hope that the comments continue on a positive vein that will be taken up by the manufacturers.
Joined: Mar 19, 2007 Posts: 310 Location: Plymouth
Posted: Sat Jan 05, 2008 10:58 pm Post subject:
What is the OS grid reference of the point with the 40 metre difference? _________________ I like mapping, I like mapping, I like mapping and I like to map!
Joined: Nov 12, 2003 Posts: 94 Location: Lancashire, England, Great Britain
Posted: Sun Jan 06, 2008 12:14 am Post subject:
Quote:
Point North="1292475263" East="-28564230" Elev="684" Text="WP6" Visible="1"/
Point North="1292460241" East="-28608820" Elev="706" Text="WP7" Visible="1"/
I noticed a slight discrepancy with Mike's altitude figures of Ingleborough Hill which (on the OS 1:25000 map) has the altitudes as 705 metres and 723 metres at these waypoint positions. Though they are not as far out as 40m. _________________ Aprilia Tuono, Zumo 550
Ipaq 2210/Fortuna/TomTom Nav6
& Road Angel 7000 + Memory Map
Grid reference for the hill in question is NN 1356 3278. Beinn Eunaich. On the map it is 989 metres on Satmap " planning" it is 942 metres.
We didn't do that hill today because of the weather. We did do another in the Ochils and also found a very small difference. Grid reference NS 9356 9982 map; 648 metres Satmap 640 metres. An OK tolerance.
I'll just keep monitoring these differences and do another posting when I have built up more info.
For the rest of the day it did what it said on the tin.
The snail dots were spot on for Hill walking, set at 5kmp. The location at summits and key intersections were within 10 metres. More to the point it showed when I was off the route in some snow and mist. easy to use with winter gloves.
Battery life (the original lithium ones supplied). Died after 6.5 hours today. But I had also used them for approx 2hrs previously over 2 Trips. So 8Hrs+ is OK for me. I did remove them religiously after each trip as advised in previous postings on this site. the small net area on the front of the carry case is a handy place to keep them.
Hope this adds to the general info.
More than happy with it after a full day on the hill.
Joined: Mar 21, 2007 Posts: 261 Location: Cambridgeshire, UK
Posted: Sun Jan 06, 2008 8:20 pm Post subject:
miket1 wrote:
Grid reference for the hill in question is NN 1356 3278. Beinn Eunaich. On the map it is 989 metres on Satmap " planning" it is 942 metres.
We didn't do that hill today because of the weather. We did do another in the Ochils and also found a very small difference. Grid reference NS 9356 9982 map; 648 metres Satmap 640 metres. An OK tolerance.
I'll just keep monitoring these differences and do another posting when I have built up more info.
For the rest of the day it did what it said on the tin.
The snail dots were spot on for Hill walking, set at 5kmp. The location at summits and key intersections were within 10 metres. More to the point it showed when I was off the route in some snow and mist. easy to use with winter gloves.
Battery life (the original lithium ones supplied). Died after 6.5 hours today. But I had also used them for approx 2hrs previously over 2 Trips. So 8Hrs+ is OK for me. I did remove them religiously after each trip as advised in previous postings on this site. the small net area on the front of the carry case is a handy place to keep them.
Hope this adds to the general info.
More than happy with it after a full day on the hill.
Good to hear it was reliable for you for 2D positioning on the hill in poor conditions - I have also found this to be the case. Like you, I was a little disappointed with the altitude reading (having just got used to the excellent electronic altimeter/GPS combo in the Garmin 60Csx), but then if the 2D position displayed by the A10 on an OS map is reliable, there's no navigational need for ultra-accurate altitude readings (and if I want to know my altitude, I can read it off the OS map using contours or spot height)
What power saving regime have you got set-up on your A10 to give you 8.5 hrs from a set of lithiums?
Joined: Mar 19, 2007 Posts: 310 Location: Plymouth
Posted: Sun Jan 06, 2008 8:50 pm Post subject:
lucevans wrote:
but then if the 2D position displayed by the A10 on an OS map is reliable, there's no navigational need for ultra-accurate altitude readings (and if I want to know my altitude, I can read it off the OS map using contours or spot height?
You do both know that the elevation data that the Active 10 displays is derived from the Ordnance Survey map data and not the 3D positioning of the GPS don't you? _________________ I like mapping, I like mapping, I like mapping and I like to map!
Joined: Mar 21, 2007 Posts: 261 Location: Cambridgeshire, UK
Posted: Sun Jan 06, 2008 8:59 pm Post subject:
robs1972 wrote:
lucevans wrote:
but then if the 2D position displayed by the A10 on an OS map is reliable, there's no navigational need for ultra-accurate altitude readings (and if I want to know my altitude, I can read it off the OS map using contours or spot height?
You do both know that the elevation data that the Active 10 displays is derived from the Ordnance Survey map data and not the 3D positioning of the GPS don't you?
I guessed that the elevation data displayed for a point was from the map file when moving the cursor around in planning mode, but I thought that when tracking in map mode, the altitude assigned to your real-time position was a GPS-calculated one. No? In which case, which of the two OS data sets is at fault? The paper map spot height for Beinn Eunaich, or the digital spot-height at that location? I think it unlikely that the A10 is incorrectly interpreting the digital elevation data in the OS file (that would be a whole can of worms, wouldn't it?) so do the two OS datasets disagree? Ooooer....
Joined: Mar 19, 2007 Posts: 310 Location: Plymouth
Posted: Sun Jan 06, 2008 9:11 pm Post subject:
lucevans wrote:
robs1972 wrote:
lucevans wrote:
but then if the 2D position displayed by the A10 on an OS map is reliable, there's no navigational need for ultra-accurate altitude readings (and if I want to know my altitude, I can read it off the OS map using contours or spot height?
You do both know that the elevation data that the Active 10 displays is derived from the Ordnance Survey map data and not the 3D positioning of the GPS don't you?
I guessed that the elevation data displayed for a point was from the map file when moving the cursor around in planning mode, but I thought that when tracking in map mode, the altitude assigned to your real-time position was a GPS-calculated one. No? In which case, which of the two OS data sets is at fault? The paper map spot height for Beinn Eunaich, or the digital spot-height at that location? I think it unlikely that the A10 is incorrectly interpreting the digital elevation data in the OS file (that would be a whole can of worms, wouldn't it?) so do the two OS datasets disagree? Ooooer....
Well I've just tried the same kind thing with Memory Map hovering over a printed spot height to see how the readout compares and find the odd difference of about 4 metres or so but then when I pont the cursor over a grid intersection the end of the cursor (in MM it's an index finger pointing) I can't get it to say XX000 XX000...the nearest I can get, zoomed in with my steadiest hand is XX998 XX003 and given that there is a spot height every 5 metres easte/north it is expected to get a bit of a difference in indicated height compared with either a contour line, spot height or even a triangulation point. though certainly not 40 metres unless there's a typo in the data file.....which there could well be given my experience of the road names (A382/A383) marks. _________________ I like mapping, I like mapping, I like mapping and I like to map!
Your point about taking the altitude from the contour line or spot height is very valid and very practical. I have just been used to using an altimeter and OS map contours to estimate my position. If the spot locator is accurate on a given contour, which it was today, then my concerns about the SM altitude reading are a thing of the past.
But from an accuracy point of view still something that SM should pursue.
re Battery setting; Power Saving - Always On.
Screen Turn Off- after 10 Mins
Use today. 4 hours on hill active use, using zoom etc, then sticking back in pocket for probably 15/20 mins and using again. Stick in rucksack until I get back home, so probably 2.5 hrs passive. I did the latter just to see how the long the battery would last, so this might not be the experience on the hill.
Joined: Mar 21, 2007 Posts: 261 Location: Cambridgeshire, UK
Posted: Mon Jan 07, 2008 4:06 pm Post subject:
miket1 wrote:
re Battery setting; Power Saving - Always On.
Screen Turn Off- after 10 Mins
Use today. 4 hours on hill active use, using zoom etc, then sticking back in pocket for probably 15/20 mins and using again. Stick in rucksack until I get back home, so probably 2.5 hrs passive. I did the latter just to see how the long the battery would last, so this might not be the experience on the hill.
If the above pattern of usage is typical for you, maybe try setting the "turn off screen" time-out to 30 seconds? The screen won't switch off until 30 seconds after you last press a button or move the joystick, by which time you've probably got the info you're after. I use my A10 in the same way, and have had no problems using 30 seconds time-out.
I haven't kept an accurate count, but I estimate that a set of 2000mAh metal hydride rechargeable batteries lasts at least 8 hours this way, and not only are they cheaper than the (very good) lithium AA energizers, but they have the advantage of no recharge memory, so if you are on a multiday trip and are staying overnight somewhere with mains power (i.e. not a tent!) then you can top-up charge the batteries every night and ensure a full 8 hours use the next day. This removes the need to carry a fresh set of batteries every day because the ones you started-out with were half-drained at the beginning of the walk.
Oh, also, if you suffer from screen flicker with lithium batteries, you'll be pleasantly surprised when you try metal hydrides!
Joined: Dec 04, 2007 Posts: 13 Location: verwood, dorset
Posted: Mon Jan 07, 2008 10:30 pm Post subject:
lucevans wrote:
miket1 wrote:
re Battery setting; Power Saving - Always On.
Screen Turn Off- after 10 Mins
Use today. 4 hours on hill active use, using zoom etc, then sticking back in pocket for probably 15/20 mins and using again. Stick in rucksack until I get back home, so probably 2.5 hrs passive. I did the latter just to see how the long the battery would last, so this might not be the experience on the hill.
If the above pattern of usage is typical for you, maybe try setting the "turn off screen" time-out to 30 seconds? The screen won't switch off until 30 seconds after you last press a button or move the joystick, by which time you've probably got the info you're after. I use my A10 in the same way, and have had no problems using 30 seconds time-out.
I haven't kept an accurate count, but I estimate that a set of 2000mAh metal hydride rechargeable batteries lasts at least 8 hours this way, and not only are they cheaper than the (very good) lithium AA energizers, but they have the advantage of no recharge memory, so if you are on a multiday trip and are staying overnight somewhere with mains power (i.e. not a tent!) then you can top-up charge the batteries every night and ensure a full 8 hours use the next day. This removes the need to carry a fresh set of batteries every day because the ones you started-out with were half-drained at the beginning of the walk.
Oh, also, if you suffer from screen flicker with lithium batteries, you'll be pleasantly surprised when you try metal hydrides!
Wow - Can other current owners of the A10 ratify lucevans battery life when using as descibed? If so it's a big improvement over the general battery life reported in this forum for the A10.
Joined: Jan 14, 2005 Posts: 19638 Location: Blackpool , Lancs
Posted: Mon Jan 07, 2008 10:50 pm Post subject:
I have managed 14 hours from a set of Lithium Energizer disposable cells, these are rated at 3000mAh, my experiances with the NIMH cells has been good but I have never tried such low capacity cells in my device to be honest.
You need to be aware that the NIMH cells output a nominal 1,2V whereas the normal bateries put out 1,5V per cell, as the device will auto shutdown at 3,35V so three cells in series rated at 1,2V only offers 4,05 volts to start with a full 0,45 volts down from the disposable cells rated at 1,5V each.
I would expect considerably longer usage than the figure I quote above in typical usage though, when a device is new I tend to play with it more than perhaps I needed to (who doesn't) - now I am used to the unit I also have the screen backlight on 30 seconds power save - what I need to try is another decent length walk if the weather holds out Whernside - Ingleborough looks good for Saturday, I will miss the third "Peak" due to daylight availability though at this time of year - Mike
Well I've just tried the same kind thing with Memory Map hovering over a printed spot height to see how the readout compares and find the odd difference of about 4 metres or so but then when I pont the cursor over a grid intersection the end of the cursor (in MM it's an index finger pointing) I can't get it to say XX000 XX000...the nearest I can get, zoomed in with my steadiest hand is XX998 XX003
I don't have MM, but I do have Anquet, (version 1.1.12), and noticed many years ago that you cannot get a 10 figure Grid Reference that does not end in either a 2 or a 7.
This is because at it's native resolution, on the screen, every pixel measures 5 metres. Perhaps Anquet decided to end their GR's in 2 or 7, and not 0 or 5!
So maybe MM decided to use 3 and 8 for their final digit.
Try it and please let me know if you can get a reading ending in anything other than 3 or 8.
Joined: Mar 19, 2007 Posts: 310 Location: Plymouth
Posted: Mon Jan 07, 2008 11:19 pm Post subject:
I can get 2,4,7 or 9...my mention of 3 and 8 was from memory......a failing memory, clearly!! _________________ I like mapping, I like mapping, I like mapping and I like to map!
Joined: Mar 21, 2007 Posts: 261 Location: Cambridgeshire, UK
Posted: Tue Jan 08, 2008 8:28 pm Post subject:
mikealder wrote:
You need to be aware that the NIMH cells output a nominal 1,2V whereas the normal bateries put out 1,5V per cell, as the device will auto shutdown at 3,35V so three cells in series rated at 1,2V only offers 4,05 volts to start with a full 0,45 volts down from the disposable cells rated at 1,5V each.
I get the feeling Mike (from the problems a lot of people are reporting with screen flicker and lock-up when using brand new Energizer Lithiums) that the A10 is actually designed to run at a voltage slightly lower than 4.5V. In fact, the A10 isn't the only GPS that Lithium AA's cause a problem with - The venerable Garmin Map 60CSx has recently had a firmware update to REMOVE Lithium batteries as an option in the set-up menu, and Garmin's latest advice is NOT to use them in the unit for fear of damaging the electronics. (Apparently, the GPSMap 76 series are not affected by this issue and can happily use lithium AA batteries.)
It'll be interesting to see what the LiPol unit actually produces if it ever materializes! (Like everyone else, mine's on back-order).
I do take your point about the narrower voltage margin 'till auto power-down that I get with the metal hydrides, but in practice they seem to maintain a steady output until the last minute, then die very quickly (as evidenced by the flaky battery indicator!) so as long as I charge them the night before a walk, I don't need to worry about the unit dying half way up a mountain. (Famous last words....)
Also, my O-level electronics is hopelessly lost in the mists of time, but can you explain why (3 x 1.2)=4.05V for the rechargeables, but (3 x 1.5)=4.5V for the disposable cells? Surely the rechargeables in series would give 3.6V?
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