Living with a Garmin: Show on Map (Tracks)
A very basic method of navigating with GPS is to store a Track on the device, and just have it showing on the map, preferably in a nice bright colour. As you move around, the map scrolls with you, and all you do is ensure you stay on the coloured line. It's the exact electronic equivalent to having a paper map and going over it with a highlighter pen.
To do this, the Track has to be set to 'Show on map'. On older Garmins (such as the Etrex Legend and Vista, etc), this is the default setting. If you 'open' a stored Track, you'll see a 'Show on map' tickbox, and usually you'll find this is already enabled. You'll also find colouring options in the same menu, and bright green is a good option unless you're in an area where the map background is green (national parks, some forests) in which case maybe try cyan, blue, or magenta.
However, on newer Garmins (basically those with the box-style main menu and the 'Where To?' option) the default setting for stored Tracks seems to be 'Hidden'. This is probably because they don't have the old storage limit of 20 and so if the default was 'Show' it could all get too confusing. So, if you are a Track user, you need to 'open' each stored Track and activate the 'Show on map' button. (Very confusingly, the button now changes to 'Hide on map' - if you see 'Hide on map', that means that the Track is currently showing. Hmm.) Again, you can set a colour in the same menu.
What is more (and what is worse), 'Show on map' seems to be not very 'sticky' - at least on my Etrex 30 - the setting sometimes doesn't survive a power cycle, and usually is reset to 'hidden' by adding any new GPX file to ones that are already loaded. (On the older Garmins it is completely 'sticky' and reliable across any amount of power cycles.)
Note that 'Show on map' is not to be confused with the 'Map' button that you'll see on the same menu page. That just switches to a map showing the Track for preview purposes - not the same thing, and not what I'm talking about here.
'Show on map' is not a navigation thing - it's just a property setting of the stored Track, to make it display in any navigational mode.
Using 'Show on map', the Garmin (old or new) can display any number of Tracks simultaneously. If you have a multi-day project with one Track per day - or a cycle event with one Track per leg - just alternate the colours and as you follow the onscreen highlight, when the colour changes, that's your stop. Or if you want to show options, you can just have 2 or more Tracks criss-crossing in the same area.
Pic 1 below shows a continuous long Track, coloured green, with a designated stop (control point) coming up and marked with a Waypoint. This is recommended for new-style Garmins. (Note in these pics, the Active tracklog being laid down in cyan.)
Pic 2 (yes, it's the same pic) shows two shorter Tracks, both colored green, split at the Waypoint. This is recommended for older Garmins like the Legend or Vista. It looks just the same, and acts just the same.
Pic 3 is the same setup as pic 2 but the 2nd Track is coloured another colour.
Pic 4 is the same as pic 3 but without a Waypoint. The split Track and colour contrast still marks the designated stop perfectly well.
(Though as a general rule, for other reasons, if you can add Waypoints that is better.)
Users of newer Garmins would probably want to navigate a Track anyway, by using the 'Where To?' button, and this certainly can work very well especially if there are a few waypoints dotted around as well. However if you want to see options, by using 'Show on map' you'll get this functionality too - while navigating along the purple line you'll see any options as you come to them, highlighted on the map in green or whatever colour you've chosen.
The same would apply if you were nagivating a Route - any Tracks set to 'Show on map' will be visible, along with the Route you're navigating.
Some basic stuff:
Living with a Garmin: Etrex Basic Setup
Living with a Garmin: Battery Runtime and Etrex Jitter
Living with a Garmin: The Waypoints Limitation
Living with a Garmin: The Follow Road Trap
Living with a Garmin: The Circular Routes Problem
Living with a Garmin: Declutter the Page Sequence
Living with a Garmin: Living with Metroguide Maps
Living with a Garmin: Waypoint Naming (for direct-style routes)
Living with a Garmin: Colour your Tracks and Routes
Living with a Garmin: Create a Route on the GPS
Top 5 GPS Tips (pdf) reprint of Arrivee article published Feb 2007
Some GPS FAQs web version of Arrivee article published Nov 2008
NEW - Garmin Etrex 20/30 essays:
Etrex 30 review reprint of Arrivee article published Jan 2012
Etrex 20 & 30, Basic Setup
Taming the Etrex 20/30: Restore the 'Page' key.
Living with a Garmin: Show on Map (Tracks)
Dakota 20 review reprint of Arrivee article published Feb 2010
Living with a Garmin: Waypoint Naming and the Dakota 20 / Etrex 30
More Garmin essays - not-so-basic:
Garmin Etrex C Menu Map (pdf, July 2008)
Living with a Garmin: Full Reset
Living with a Garmin: Track, Route or Autoroute
Living with a Garmin: Three Ways to Beat the Waypoint Limit
Living with a Garmin: Three Ways to Beat the Trackpoint Limit
Living with a Garmin: Less is More
Living with a Garmin: Add Contours to your GPS Maps
Living with a Garmin: Struggling with GPX &... More GPX
Living with a Garmin: Screens you don't see every day
Living with a Garmin: Downgrade your Mapsource
Living with a Garmin: Put an OSM Map on your Garmin
Living with a Garmin: GPS Soak Test files to test your GPS waypoint capacity
OpenStreetMap and Mapsource Add OSM to your Mapsource collection
A Google Maps Workflow Create, Edit, Save, Share and Export a route