Will a GPS unit...........

[Jamie]

So with the DVD version of the City maps, I can load the software onto my computer and do all my mapping on their software?
Can I load it onto my work computer and my home computer?
Thanks

[Biggsy]

Some of the complications mentioned above might not apply to what you're getting.  I don't know.  Have fun anyway.  It's all amazing technology.

So with the DVD version of the City maps, I can load the software onto my computer and do all my mapping on their software?

Yes indeed.

And I managed to install mine on two different computers, though I can't remember the details of the process.  Someone else will tell you more, no doubt.

[frankly frankie]

Do the City Navigator maps have all the tiny roads?

On Garmin's website you can view the coverage of each of their map products and drill down to see the detail coverage in any area you're interested in, before you commit.  This stuff isn't easy to find, but it is there, for example:
Garmin website / Maps / Buy Maps / On the road maps / Europe / City Navigator Europe / View Coverage
shows an overview map of the coverage, clicking on that overview gives a (clunky) zoomable pannable view of the entire City Navigator EU map, down to street level.

Likewise of course on the OSM website you can again zoom in to see the detail coverage of the area you are interested in.  (Though in the case of OSM there is a very small chance that, because the map you download will be less up-to-date than the one you see 'live', some information will be missing in the downloaded version.)

In both cases, what you see on the PC won't look the same on the GPS - but the mapping, ie detail and coverage, would be the same.

[frankly frankie]

Now, ISTR seeing something about alternative mapping being used by the device (manually selected or otherwise), but is that constrained by how you've bought you maps from Garmin ?
eg the preloaded sdcard means you have to put OSM on the device, whereas with the device-tied version do you have to download onto the device, or do can you download to sdcard (I'd guess with some encoding to ensure only that device can use it) together with OSM also on the sdcard - or does OSM go on the device.
I guess there's also the question re a preloaded sdcard of what the device does when it's logging/archiving - does a preloaded sdcard prevent this.

Biggsy was right - it's complicated.  To answer the last bit first, no.  The card won't be write-protected, which is scary in itself.

'Older' GPSs - including the Etrexes 'Cx' series but not the new Etrex 10/20/30 - any map must be on the SD card.  It's either transferred to the card from the software included on the DVD version (wiping any other map on that card, and locked to that GPS), or you buy it preloaded on a card (not locked), or you copy a specially-formatted map file (such as OSM) onto any old blank microSD card (not locked).
The GPS can only read one map file at a time (though that one file can include several different and separate maps - possibly including contours as a layer as touched on above).  Even though the DVD version is locked, if you enjoy messing with different maps on the GPS, it is definitely preferable.  If you buy the SD card version of City map, you can still switch to OSM simply by carrying 2 cards (but you have no way of overlaying contours on City, for example).

'Newer' GPSs - including the new Etrex series as well as the touchscreen models - can read more than one map file at a time, and can store map files both on the SD card and in memory.  Tracks can also be semi-archived in memory.  So, for users of the new type, I think the SD card version of the City map may make quite good sense, as it's cheaper.  They can still load OSM and contours into memory and have access to all maps in any combination, and the track-archiving needn't impinge on the SD card.  (Of course, the GPS internal memory isn't write-protected either, now that's really scary! - I recommend backing it up to HD, first thing you do.)

[andrew_s]

or you buy it preloaded on a card (not locked)

As I understand it, City Navigator on SD card is locked, but it's locked to the card.
So you can back up the data on the card in case of accidental deletion or overwriting, but if the card gets damaged or lost you can't restore the backup onto a different card.
The card can be used freely in any GPS.

The DVD version gets locked to a specific GPS. If you lose the card you've written it to, you just write another card. If you buy a new GPS, you need to buy a new version of the map data.

The cards are small and easily lost if you keep swapping them.

[henshaw11]

Many thanks folks ! - that clarifies things a lot, and ties up with odd snippets I'd picked up.

FWIW I'm considering the Etrex 30  - depends on how the display compares to those of the Oregon/Dakota but I've no real button/touchscreen preference.

Jamie - where did you get yours from - Go Outdoors ?

[Jamie]

Yep - Go Outdoors.

[wilbt]

You can use two GPS units for one software for the licence.
Also if you lose the GPS unit and buy another one you can unlock from one serial no, and register with a new one.  I've done it because the GPS was faulty.  You will need to ask Garmin support

[Bledlow]

I guess there's also the question re a preloaded sdcard of what the device does when it's logging/archiving - does a preloaded sdcard prevent this.

Biggsy was right - it's complicated.  To answer the last bit first, no.  The card won't be write-protected, which is scary in itself.

... (Of course, the GPS internal memory isn't write-protected either, now that's really scary! - I recommend backing it up to HD, first thing you do.)

This seems to be general, & I'd definitely back up straight away.

I think the SD cards can generally be restored from a backup if accidentally overwritten - but only the map that was originally on the card, & only to the same card, as in the example Andrew_s describes. This is the same for Satmap, but they'll replace a damaged card (if you return it to them, & show proof of purchase) for less than the cost of a new one. They say "a small fee", but I don't know what they consider small.

[Panoramix]

Regarding the OSM data, the quality is dependant of where you are, in the Bristol area it is definitely better than the Garmin maps which omit cyclepaths. In germany and Switzerland, it looks very good. In France it is not there. In Wales it is still patchy in some places but perfectly usable.