RickyB_uk

It depends on what you are after. OSM doesn't yet have 100% road coverage of the whole UK yet, but there are now quite a few areas where it does. For the rest, the major road network looks pretty complete and I've always found using the talkytoaster OSM maps on my GPS to be very good. In some areas, footpath coverage is very good, in others, almost non-existant. One other advantage is that if you come across a footpath/road which isn't on the map, you can edit it directly on OSM so that it is. I have no idea what the Metroguide maps look like, but if they're a few years old, then they won't be 100% complete either. One of the OSM advantages is that, being crowd-sourced and directly editable, new roads can sometimes appear within hours of them opening.

But I disagree with your second point - if you come back on a second day you are also running the risk that the satellite alignment on the second day is, in fact, giving you less accurate data than the first day. Unless you are privy to some other data that's telling you your co-ords are more accurate the second time you visit??? Of course it *might* give you worse data, because there is some degree of randomness, but on average it will improve your data. Effectively, it gives you an almost independent 2nd sample. It's not quite independent, but let's imagine that it is. Imagine that the 1st day's sample was 6 metres to the north of the true location. If you take your 2nd independent sample, then it could also be 6 metres north, but is equally likely to be 6 metres south, west or east of the true location, or somewhere inbetween. If it is 6 metres out, and anywhere other than exactly north, then your averaged coordinate is better than the first sample alone (e.g. suppose the 2nd is 6 metres east - then your averaged coord is now only about 4.25 metres north-east). I'm not saying that all cachers should take multiple averaged samples, because as you say, most of the time one averaged for a sufficient length of time will usually give very good results. Of course they are subject to the same local conditions - but if you publish coords which are out by 15 metres+, that affects all future finders, on every visit. When finding, if your GPS has got poor reception, then that affects you, on that visit alone. All I'm trying to say is that the cache owner ought to make a reasonable stab at getting the best possible coords that they can. I've seen quite a few recently which were out by 15m, 20m, even more sometimes.

The finder doesn't need to come back, but the cache owner should take more than just a single waypoint. You cannot guarantee the accuracy of any waypoint, but you can reduce the chance that the cache coords lies more than a significant distance away from where it should be by taking more samples. A single waypoint is a sample of 1 point from, essentially, a random distribution of points, approximately centred on where the unit actually is. If your GPS suggests accuracy of 7m, then that usually means that the chance of a single waypoint being inside 7m from the true coords is approximately 2/3, and that 1 time in 20, the waypoint will lie more than 14m from the true coordinates - and you'll have no idea which at the time. If a cache owner happens to choose that 1 in 20 waypoint, and leads future finders astray by 14 or more metres, that isn't ideal. If, instead, they take a waypoint by averaging over 10 minutes, that is 600 sample points. They're not statistically independent, but taking 600 sample points reduces the chance that the overall averaged point is really far from the true coords. If you come back and repeat on a different day or different time of day, you are minimising the chance that the particular satellite alignment that you had on the first pass is causing your sample points to have a certain bias (e.g. if the points are being reported as too far north).

All very commendable, but - unless your finders go to the same lengths and return for another set of readings on a separate day - I wonder if it isn't just a little wasted? The finder is only trying to, well, find the cache. If their GPS has poor reception the one time they are there, then that will affect only them. If they came back a different day with better signal, and the published and true coords are very close, then their units will take them closer. If a cache setter takes only a single waypoint, then if their GPS had poor reception the one time that they were there, every cacher who attempts to find it will have ther unit initially take them elsewhere - and the cache will appear in a slightly different place on the GC.com maps. Granted many will not use their GPS for the last bit, but it can make a difference - e.g. the cache page / GPS map etc. might show a cache on the opposite side of a road/river to where it really is - perhaps in the latter case with no bridges for half a mile etc. - or there could be a multitude of items matching the hint in the vicinity. It's not fair on potential finders if they have to spend several minutes searching in the wrong place - just because the CO couldn't be bothered to come back and get another waypoint.

Being out by 3 metres is very picky, and the individual reading by the finder may not be that accurate anyway. However the cache owner should really have averaged the coordinates over several minutes (preferably coming back at a different time and averaging another waypoint etc.) - or taken multiple waypoints and taken an average. By doing this a sufficient number of times, you should usually get pretty good coords. Any cache where the coords are out by more than a few metres should be pointed out IMHO. Too many caches have really poor coords (consistently > 10-15m out etc.). Finding caches by GPS coords is, after all, the whole point.

You could have it as a puzzle cache where cachers work out a few numbers in advance - could be any topic - then in each film pot corresponding to the answers is partial coords for the real final stage (with decoy partial coords in the incorrect puzzle answers). That would be a lot more appealing to me than rifling through a hundred or more decoy filmpots

It's more trouble than it should be. When I have a trackable in my posession - every time I log a new cache find I am presented with an option for those trackables; "Visited" or "Dropped off". That's really easy to do. Why is the same not true when I log a cache with a trackable inventory? At the moment, it seems I need to go back in via a different menu. E.g. when I log a cache find, it could provide me with a list of trackables supposedly in the cache and then a number of options e.g. "Picked up", "Discovered", "This item wasn't here" etc. For the first two, it could still ask you for a tracking number to confirm pick-up etc. Of course things like this wouldn't stop mallicious thieves, but it would go some way to stopping accidental non-logging of pickups.

The moon's around 250,000 miles away (it moves about a bit anyway- they do use lasers to measure how much), and light travels at 186,282.3970 miles per second, so about 1.34 seconds. Give or take. I think that's close enough so... DING to Simply Paul. Although my sources suggest it is 1.26 seconds. Although the moon has no light source of its own, it does reflect the sun's light and, therefore, light does come from the moon.. Looking around 250 years into the past and future, the closest the moon has gotten was 356,375 km (224,441 miles). The futhest the moon will be from the earth is 406,720 km (252,724 miles). The average is 384,401 km (238,856 miles). These equate to time delays of 1.19 seconds at the closest point to 1.36 seconds at the furthest point, with an average of 1.28 seconds.

So that was the problem then. As far as I know, it must be just called gmapsupp.img - no extra letters before or after are allowed otherwise it won't recognise it.

You don't need to take the card out of the GPS - just put the GPS in mass storage mode by going to "Setup"->"Interface"->Press the button to select "Mass Storage Mode". As long as you have connected the USB cable to the computer - you should now see the GPS as a new drive (for me it's on the K drive). You can do all of your file manipulations on there just as you would for any normal computer directory. To get back to normal mode - just press the "On" button for a short time. If you've just loaded a new map correctly - it should recognise it straight away - and will probably show a thin progress bar on the screen when loading it for the first time. When you turn on, you should get a second copyright notice which says something like; © AND IRELAND © OPENSTREETMAP.ORG CONTRIBUTORS and a couple of other lines If you don't see that, then the file hasn't loaded somehow. You need to check that there is a file called gmapsupp.img in the Garmin directory on the MicroSD card. If there is, might just be worth checking by viewing the properties that it's correctly an IMG file (and not just, say, that you've renamed the zip file without unzipping it first - sounds stupid - but I've done that before...) If the copyright notice comes up, then the maps are on there - but they might not be displaying. Go to "Setup"->"Map" - and you'll get a load of options for setting up the map display. At the top, for me there are 6 icons - go to the 5th one which is an "i" in a blue circle. It shows what maps are loaded onto the MicroSD card. The maps will only show if there is a tick next to them. For me they all have names like "OSM-tile: 12345678, UK Mapset with Contours, Jan 2009". Scroll down to make sure that they have ticks by them. Go to the left-most icon. It's a red "N" with red arrows surrounding it. Check that the option "Detail" is set to "Most". Fewer contours appear if you set lower detail levels. When testing it, make sure you zoom in a fair bit - as you zoom in, more detail is shown. If the maps are on there, and still no contours - then try scrolling to somewhere else in the UK - perhaps there's a problem with an individual map tile and it hasn't loaded correctly. If that occurs - then the GPS will default to the standard issue map whenever the cursor position is somewhere over that map tile. When I did my testing - I looked at an area of the Peak District near the Cheshire/Derbyshire border - which seems fine. I don't think there's any particular reason why it shouldn't work on your unit - you have the same model as me - and others have managed to get it to load on similar models.

I've just loaded the contour version on my eTrex Vista and it's fine - although if I zoom out - the vertical height between contours increases - so that unless I'm in a hilly area - not many contours show up. I've just scrolled over to the Peak District and it looks great!

I could possibly pick it up I suppose. I'm not particularly far away. I've had a reply back from the finder saying that it contains a list of many GCXXXX numbers with their associated hints. One of the ones mentioned it GC1HFQJ LS Lowry

I got sent this message as someone who has set some nearby caches (further north). If the finder has found it whilst out walking - then it's easily possible that the find was not at his home post-code - but some distance away. Might be useful to get some info about what is in the book to help identify its owner - e.g. it might have which caches have been done on what dates - which should make it straightforward to find. Could it even be a log book from a specific cache that has somehow ended up some distance away?

You say the "counties being used today", but that's not 100% clear cut. I would personally go for the "ceremonial counties". These are proper legal entities, and have a lord lieuitenant for ceremonial purposes. They should not change much in the forseeable future. I would say, particularly in England, the ceremonial counties are what most people would call their county. The boundaries shown on the OS maps are "administrative counties" which are usually areas with a council. This includes all of the Unitary Authorities - so your home town was in the Greater Manchester ceremonial county - but is in one of the Metropolitan Boroughs for its administrative county - because Greater Manchester doesn't have a council anymore. The situation in Wales would put your house in Clwyd if you go with ceremonial counties (called preserved counties in Wales)- Flintshire with administrative counties - but going for the admin. counties would also include, say, Conwy or Wrexham as a county. There are major local government changes afoot for some areas in the next couple of years. In 2009, several large counties will be split into one or more unitary authorities - e.g. Cheshire will cease to be an administrative county - instead there will be two unitary authorities in its place - West and East Cheshire. The ceremonial county of Cheshire will remain unchanged (it would include West and East Cheshire, as well as Warrington and Halton UAs) I would say, in light of future local government reorganisation, we use ceremonial counties which shouldn't change their borders significantly. The full list for England is here. Similar lists are available for the other parts of the UK