Jump to content


  • Posts

  • Joined

  • Last visited

Everything posted by AlunS

  1. "Lock on Rock" ??? That's a new one on me I assume you mean "Lock on road"? Anyway, no, she doesn't have this set on, and neither of us have any routable maps installed either except the basemap,and believe me, there are no roads on the basemap in this area for a long, long way.
  2. We both have WAAS on, and no, neither of us was wearing a tinfoil hat Both units are at the latest revisions, both for firmware and GPS, i.e. 2.60/2.60 for the Vista and 2.70/2.60 for the Venture (for some strange reason they jumped from 2.50 to 2.70 for the Venture, even though the list of changes is identical as far as I can see to the list for the 2.60 Vista update!) Anyway, it's an odd one all right .. on the first part of the walk, walking alongside the lake, it's a random movement, yet later on when we got out of the trees, and on the return (the lower track on the map) the track mimics the shape of the correct one, but is displaced by a certain distance that seems to increase as time goes on.
  3. OziExplorer with a scanned in map (Harvey's Wicklow Mountains (Ireland) map from here)
  4. Maybe, but I've noticed some differences between my Vista HCx and my wife's Venture HC when in bad reception conditions (i.e. tree cover). We both carry our GPS's in the standard etrex carry case attached to the shoulder straps of our rucksacks. I get a perfect track every time and she gets tracks wandering about all over the place. Here's an example from last weekend .. my track is in blue, hers is in red.
  5. http://en.wikipedia.org/wiki/Irish_Transverse_Mercator Irish Transverse Mercator (ITM), is the new geographic coordinate system for Ireland. ... ITM and the older more established Irish Grid will (initially at least) be used in parallel. As a result ITM coordinates had to be obviously different so users would not confuse the two. This was done by shifting the ITM false origin further into the Atlantic and thereby creating substantially different coordinate numbers for any given location. While OSI and OSNI intend to supply map information in the older Irish Grid format into the future, the Irish Institution of Surveyors has recommended that ITM be adopted as soon as possible as the preferred official coordinate system for Ireland. IG is the only one of significance .. ITM is irrelevant for recreational users. All the current OSi maps are Irish Grid (IG) based on a modified 1965 Airy ellipsoid and will continue to be so for a long time to come. The problems arise due to datum conversion in the GPS itself since internally it uses WGS84, and the conversion that can realistically be done (using lookup tables and interpolation) in the GPS will have inaccuracies which are not relevant for most recreational users but are quite significant for professional ones, hence the adoption of ITM that is based on WGS84 (actually GRS80 and ETRS89). Also because of the false origin, to eliminate any confusion between the two systems, ITM coords are quite long and a bit unwieldy as a result. See http://www.osi.ie/gps/overview/gps.asp
  6. Well, I thought the problems with the calculation of total ascent on my Vista HCx had been sorted out, but today I went on a hike with a calculated 800m or so of ascent, and the thing reported 1657m ascent, more than double. Looking at the track log, I see myself in a few places jumping up and down 10m or so, several times in a row, while I'm actually standing still! The only thing I can think of is that it was a particularly windy day today, and I'm wondering whether that could have been the problem. I have the GPS in a case mounted high up on my rucksack strap, so it would be quite exposed. So, does anyone know if the altimeter in the GPS would be particularly affected by the wind like this? If so, then in a windy place like Ireland, it renders the altimeter next to useless for this purpose.
  7. FWIW my wife's Venture HC seems to be suffering from the same problem if it's left for any length of time without batteries in. We're not talking massive lengths of time here, only a week, and any other etrex model I've had has been capable of maintaining it's internal clock for that long.
  8. What 'real world' is this then? As others in this, and other threads have pointed out, there is no single 'correct' answer to how far you have travelled. The distance as measured by your track log (which is highly dependent on what settings you have chosen) is an approximation, as is that measured by the odometer, they're just using different techniques. An analogy I always use is that of fractals. Mandelbrot, who discovered these, wrote a paper entitled "How long is the coast of Britain" .. at first look a simple question, but as you look at it more carefully you realise that the answer depends on the scale with which you look at the problem. If you measure it using a map measurer and a 1:250,000 scale map you'll come up with one answer, if you walk the coastline with a GPS hugging every inlet and cliff edge, you'll get another, much larger answer. Basically, the closer you look, and the more detail you take into account, the bigger the answer, there is no 'right' one, only the one that fits your specific purposes. It's the same with track logs. If you set your track log to take one point every 15 minutes or 1 mile, it'll give a very different answer than if you'd set it to every 1 second or 3 feet, say. If you could measure every single little meander down to inch level accuracy you'd get yet another answer which would be higher still than the default track log settings would tell you. Which one is 'right'? Who knows. FWIW my ancient etrex Venture also used to display a reading that was between 5 and 10% higher than what the track log told me, but the kind of terrain I walk over means I'm very seldom walking in anything resembling a straight line for more than a few seconds at a time.
  9. My Vista HCx reported 748m of climb on my hike yesterday which seems to correspond roughly to what I was expecting (just looking at the map, the major climbs added up came to about 700m). I've tried many different pieces of software from the Internet to analyse the track logs, but they all seem to wildly overestimate, presumably because there's little smoothing going on, so any noise in the elevation data plus the fact that were I am, the terrain is extremely uneven (it's those peat hags again). The closest match I got was from a piece of mapping software I use produced by the Irish national mapping agency, which I suspect uses accurate local DEM data to calculate total ascent from tracks rather than the GPS data and that came up with 739m, which is pretty good.
  10. All being well, I should be out tomorrow with mine.
  11. There's also transparent contour maps available for free from http://www.smc.org.uk/ContourMaps.htm that you can overlay on top of CN Europe.
  12. Nope, it's not covered at all. If you load it into Mapsource you can see the outline of the island, and outlines of the major towns ... no contours, no roads, no nothing. It's not selectable as a tile, much like Ireland, part of which is visible as well when you view it.
  13. AlunS

    Vista startup.

    Well, I did the 'fridge test' (it was in there for a good hour, before I took it out) and no problems as yet. We'll have to wait a bit to see of it's a definitive fix or not. On the subject of other H series GPS's having the same problem, all I can say is that my wife's Venture HC hasn't suffered from the problem once, and it's been used as many times and in exactly the same temperatures as my Vista HCx. I've just hooked the Venture HC up and ran WebUpdater and it reports it being up to date at 2.50/2.60.
  14. I have it set to Auto/Normal just like you. The logs I get on this setting are plenty detailed enough for my purposes. What are you using to download and display them? Maybe whatever you're using is doing some filtering or track point reduction before displaying it?
  15. Your wishes have been answered ... Changes from version 2.50 to version 2.60: * Correct German translation of 'delete all waypoints'. * Fix data card unlock failure when 2 cards of the same map set are used in one device. * Improve sun times for polar regions. * Fix issue where ETA in non motor vehicle modes can be unreasonably short. * Increase precision of distance measurement to the cursor on the map page. * Allow backlight adjustment on the track back point selection page. * Fix shutdown when editing Estonian Grid coordinates. * Correct daylight saving time for New Zealand. * Improve selection of the names of cross roads with NT maps. * Correct potential shutdown when viewing a vertical profile. * Correct European word translation of 'Find' and 'Mark'. * Support multiple languages in American version. * Fix screen fading issue in cold temperature. * Correct total ascent calculation. * Correct direction symbol of vertical speed. * Fix reboot issue of GPS firmware update. * Correct battery issue of lithium battery.
  16. No idea. The maps from the SMC were made using DEM data derived from Shuttle SRTM data which is in the public domain and freely available from NASA, so maybe.
  17. You're right GB Topo doesn't cover it. Luckily though, CN Navigator Europe 2008 has a good amount of detail as far as roads go, and you can overlay it with contours from here http://www.smc.org.uk/ContourMaps.htm (they're transparent so CN shows through.
  18. UK maps are aligned with BNG (British National Grid) not True North. What you set the GPS to will depend on how you're using the GPS in combination with maps and a compass. Personally I set mine to magnetic, so that the bearing I see on the GPS corresponds with what I see on my compass (mine doesn't allow compensation for declination).
  19. AlunS

    Vista startup.

    Got it again on mine at 0 celsius (that's 32 Fahrenheit for all you metrically challenged people!) yesterday. My wife who has a Venture HC has never seen this problem. I assume the whole H range use essentially the same hardware platform so it is a little odd.
  20. Hmmm, maybe you're right .. I was squeezing reasonably hard to make sure I covered the hole completely, and subsequent tests show that if I just cover the hole lightly it doesn't happen, but if I squeeze the case as well a bit it does. My latest theory then is that what's really causing the problem is me removing it from the case I have. I have this case ( https://buy.garmin.com/shop/shop.do?pID=814 ) that I also had for my old etrex Venture, but the newer models appear to be slightly bigger and are quite a tight fit in these cases. I have the case more or less permanently attached to the shoulder strap of my rucksack, meaning I have to take it out of the case to use it, and it's necessary to grip the thing quite firmly when removing it from the case. I did a few dummy runs with it in the case on my rucksack, and it appears I'm gripping it with my thumb in the groove over the hole which is a pretty natural place to grip it if you're trying to remove it from a tight case. I think I may have to invest in another kind of attachment, either the button clip or the stretch holster. Has anyone had any experience, good or bad, with either of these? https://buy.garmin.com/shop/shop.do?pID=1035 https://buy.garmin.com/shop/shop.do?pID=1034
  21. Got out of bed the wrong side this morning did we? I'd disagree 100% with your premise that it's 'incredibly difficult' .. As I said, I hold the unit in my left hand, despite being right handed as it makes operation of the click-stick easier, and means my hand doesn't obscure the screen. In this position my index finger falls naturally into that groove, especially if I have to use the click stick when the support given by my finger from behind makes that easier too.
  22. I was being a bit puzzled by sudden spikes or glitches in the altitude in my track logs. Suddenly the reading would suddenly plunge 20 metres or so and then pop back up again, sometimes jumping the same amount into the air. Anyway, to cut a long story short, I discovered that it was due to me taking the GPS out of my holster, to check on one thing or another, or to use it to navigate to a waypoint, and holding it with my left hand index finger nestled in the convenient groove in the back of the unit ... yes, where the little hole is for the altimeter sensor!!!! At least I know know, but it does make the thing a lot more difficult (for me at least) to hold properly ... that groove on the back looks like it was designed from the outset for a finger to nestle in it, so why put the sensor hole there where it's just asking to be covered up?
  23. Apparently it indicates how good the day is supposed to be for hunting and fishing, but since I do neither I haven't a clue how it works this out. I wish there was a way to switch the stupid green fish off, but I haven't found a way yet.
  24. What a strange reply! Well, it's highly unlikely it's a hardware problem, seeing as the altimeter itself would appear to be perfectly OK. It sounds like a similar problem to the problem with the odometer to me, i.e. only registering ascent when over a certain speed (not sure whether this is horizontal speed or vertical speed). In which case it's a firmware problem. Either way, it'd be a trivial thing for them to test for themselves. Sounds like a good test. If the height gain is more accurate when in the car as opposed to when you're cycling that would tend to point to vertical speed being an issue.
  25. groth .. any news from Garmin on this one yet?
  • Create New...