N00b Questions about Geocaching in Scotland without cell data

The husband and I have been geocaching all of twice. Both times near home (US) and both times we used our smart phones as GPS-esque devices, and had access to the geocaching.com web site & app the whole time.

In September we will be vacationing on an island in Scotland which has a few geocaches we might attempt (nothing too difficult - we’re not ready!)

However, I am a bit mystified by how it would work. According to locals there is very iffy cell coverage on the island and we might as well forget about getting a decent data connection.

Thus I have some very naive questions.

  1. Do we buy a GPS? If so, what kind? Do all GPSes work everywhere or do we need a UK-specific one?

  2. Explain to me how a GPS will work if cell data doesn’t. (yes I am that ignorant!)

  3. If you’ve ever geocached without a smart phone, do you take printouts of cache info with you as you trek?

  4. We have OS Explorer Maps of the island (1:25 000) - is that an appropriate scale?

Who wants to tutor me in geocaching? :smiley:

Nothing specific to geo-caching here. More about GPS and cell-assist.

The thing about most mobile phones is that they have quite wimpy GPS capabilities. This is a function of the power draw and the limited antenna available. In order to make the GPS in a mobile phone function more usefully, phones look around at the nearby cells, and work out a fast approximation to where they are. This knowledge makes the job of the internal GPS receiver much easier. With a very good clue as to where it is, and what the precise time is, a GPS receiver can lock onto the signal from the GPS satellites much much faster. The difference in time makes the difference between a useless GPS capability, and a quite reasonable one. Cell assist also helps in areas with lots of buildings, where there is not much sky visible, and GPS really struggles.

Without any cellular assist a typical mobile phone will still navigate with its GPS, but it will struggle at best. It may take a long time to settle down and achieve a lock. So much so that you could probably forget geo-caching.

A GPS receiver will work anywhere on the planet. They receive signals from satellites in orbit around the Earth, and work out your position from the very precise knowledge of those satellite’s orbits and very very precise timing of those signals. The GPS satellites carry atomic clocks to ensure the needed precision. Famously they are so accurate that they need to take into account general relativity in order to maintain this accuracy. The deep internals of how the satellite signals allow you to work out your position is complex, but at its base, so long as you can see four satellites (and they are in reasonably well separated locations in the sky) there is enough information for the receiver to work out what the time is, and hence how long it took the signals to arrive from the satellites. That allows you to triangulate your position. Modern receivers use as many satellites as they can see, so when there are more than four the precision improves. They also use a lot of very spiffy algorithms to filter and predict what is going on with the signal, and from this they can achieve precision that is as close to pure science fiction as you may like.

A dedicated GPS receiver will have capabilities that make your phone’s GPS look very mediocre. Cell-assist is a cheap way of approximating what a good dedicated receiver is capable of.

Not geocaching specific, but I use the Gaia app:

Gaia home page

when I am going to be hiking outside of cell coverage. I can download topographic maps, and there is an option to turn on GPS on my phone while disabling cell and wifi in order to save battery. Perfectly usable offline.

Not sure if it has maps for Scotland, I’ve never tried it outside the US.

Personally, yes, I’d buy a dedicated GPS if I were doing geocaching in a non-coverage area. You can do it with the mobile without coverage, as others have said, but it’s more of a pain.

You shouldn’t need a UK-specific one, most handhelds I’ve worked with have worldwide mapsets - I’ve mostly used the Garmin e-Trex 10, which has paperless geocaching support (so - download the cache GPX file and it’s all on the device, no printouts needed) and runs to $127 here ($190 if you want a colour screen in the etrex 20, used that too, not worth the price differential just for geocaching).

This is a comprehensive discussion about GPS and geocaching.

For walking on a Scottish Island, you should take advice about what to wear. The famous quote about Scottish weather is that “You can have all four seasons in one day.” I would think that a good pair of boots would be essential.

Thank you - this was fabulously informative!

I think we will give this app a try, along with a dedicated GPS + maps n compass n stuff.

Thanks for the recommendation for specific models. I’m curious what circumstances might the color screen be warranted for, if you think it’s overkill for Geocaching. Serious wilderness trekking?

Thanks - I will read that site over thoroughly.

Our intended clothing would be:
Keen hiking shoes (probably not boots because the terrain we will be traversing will not be super rugged)
Quick-dry hiking pants
Waterproof jacket + pants
Gloves & hats

Will look at more detailed clothing recommendations before we set out.

Any time you need to read a coloured dataset, like a topomap, aerial photo or geomap. I’ve used them for geological mapping and for botanical surveys.

You can still your your phone with the geocaching app. Just create one or more pocket queries on the geocaching website that includes all of the caches you want to visit. The results of those pocket queries will show up on the phone app and your can save them to the phone. When in Scotland, just find the desired cache in the offline list and geocache a per usual. I’ve done it this way many times. Even in areas where you have good coverage and are planning a geocaching outing it’s a good idea to store the caches you are interested in in an offline list. I can never tell when you’ll have bad reception out in the woods or the geocaching site itself be be down.

Back in the day I thought half the fun of geocaching was hunt itself. With clues and sorta directions and stuff.

Now it’s just using a GPS to get to the actual target?

Can I buy a robot to do my coloring book now?

Get off my lawn.

I thought that geocaching originated with cheap commercial GPS? And even with GPS, you still need to trek overland to reach the spot, and then find the right rock or tree stump or whatever within the margin-of-error circle.

Don’t worry Bill. GPS still has an accuracy of a couple of meters so there is still quite a challenge in finding a mirco cache in the woods. If you really want a challenge then go out caching with nothing but the satellite photo in hand.

Ask away.

I disagree about the GPS capabilities of modern smartphones. When I am overseas I often have data turned off and/or am up in mountains with no phone service. I’ve never had a problem with the GPS.

Of course, you won’t be able to use online maps with no signal, so make sure you have an app with downloaded maps. I use Viewranger, which is very good and lets you cache areas of free online maps before you go, as well as downloading commercially available topo maps etc.

This is my experience as well. My iphone has always been just as accurate as my GPSr when looking for tupperware way out in the woods. Seeing as how the GPS receiver in my iphone is capable of tracking both GPS and GLONASS satellites ( I don’t know if it tracks BeiDou or Galileo yet, I’ll have to research that), it almost never loses its position lock in areas where my GPSr will.

I am somewhat of a GPS freak. My first GPS was a Garmin model back in 1998 I think. Used it to navigate the desert in my 4x4. It needed an external antenna on the roof, otherwise it struggled. I had a few more Garmins including a 296 aviation type that didn’t need an external antenna if you didn’t bank too hard.

The smarphones from known brands in the past 2 or so years are *amazingly * sensitive. I am now in my bedroom holding an OnePlus one. It sees 20 sattelites with good reception. I am under a shingles roof with insulation below and the walls are made of heavy silica bricks. There are 2 smallish windows, neither of them sees much sky.

Under these conditions no dedicated GPS I own made prior of 2009 would see *anything *. It’s probable that newish dedicated sets are much better now, but as I said, smartphone GPS is damned good this days.

All this regardless the “assisted” part that can give you a partial fix by using cellular and/or wifi triangulation and to update the almanach so that the GPS satellite fix is almost instantaneous. I’m talking about the quality of the sattelite receiver.

Looks good to me. My daughter went on a safari recently and wore her hiking shoes on the plane to save weight. Waterproof pants may be overkill - if it’s that wet you will probably stay in the dry. The main problem on Scottish islands is wind, which can be pretty fierce at times. The scenery is worth it though.

Wind = no midges though, so swings and roundabouts.

Avid cacher here. Your best bet is the geocaching app from the website (Groundspeak).
That allows you to search and save caches to your phone before you go. Speaking as an iPhone owner, the GPS and saved map functions work without cell service. The saved caches will have all of the info you need. Size, description, hints, etc.