Androids and iPhones are a lost traveller’s best friend, thanks to their capacity to pinpoint a user’s location on a GPS-powered map and outline directions via car, foot or public transport.

But your smartphone can also help you plan ahead for your trips, by plotting a custom map of landmarks you’d like to see, and help you look back at a trip, by mapping your route as you go.

Planning ahead
This winter, Branden Etheridge used Google Maps to create a custom map to track all of the places he would like to see someday. Etheridge, who works for Massachusetts Institute of Technology in Cambridge, is an architecture buff, so he dotted his map with architectural gems, including London’s Swiss Re building and the Chicago’s Frank Lloyd Wright buildings.

 “The idea is that whenever I am anywhere near these places, I can [open Google] Maps on my phone and remember that, at one point in time, I really wanted to see something nearby,“ Etheridge said. “When travelling, there is always so much to do, that you might forget that there was this building just outside of town that you really wanted to see.”

Brad A Johnson, an award-winning LA food critic who travels the world reviewing restaurants for magazines like Bon Apetit, also finds it helpful to plot specific sights before leaving the house.

“Whenever and wherever I travel, I always have at least a dozen different restaurants and hotels that I need to check out in a very short amount of time,” Johnson said. So before his trip, he adds all of the stops to a personalized Google map and views the map on his iPhone while he’s on the road.

Viewing a customized map is easiest on Android devices. Just create a map from your desktop computer (Google offers this one-minute, map-making tutorial) and save it to your Google account. On your smartphone, fire up the Maps app, click on Layers (which is the icon that looks like a stack of squares), and click on My Places, to see the itinerary you built.

iPhones, on the other hand, require a little extra effort to see the custom maps you’ve made. The fastest option is to download a free app called My Maps Editor, which Johnson uses to view his customized maps on his iPhone or iPad. Alternatively, you can open your phone’s browser and log into Google Maps, instead of using an app. Click on the menu and select My Places, then Maps.  Brower based map-interfaces, however, tend to be slower than app-based ones.

Bing has a similar tool for making custom maps, called My Places, but it doesn’t presently offer a way to import those maps into Windows, Android, or iPhone via the relevant Bing maps app. AOL’s Mapquest offers a complicated system for exporting and importing data to phones — a method best left for Web programmers.

Looking back
If you want to track where you’ve been, instead of where you’re headed, you can download several apps that export your smartphone’s GPS tracking to an online map. For example, maybe you skied an interesting route and would like to see your trail up and down a mountain on a Google Earth map. Or maybe you would like to document the route you took while wandering around a town.

The simplest route-tracking option is the free RunKeeper app, available for Android and iPhone devices. Though intended for joggers, the app will keep track of where you are going and export your route to a Google Earth map (use the Advanced Options while on the route page).

If you and your travel partner are splitting up for part of your trip, you can see each other’s locations in real-time by using Life360 Family Locator (Android; iPhone;  free). Life360 claims that its app has been instrumental in reconnecting families after real world emergencies, such as the Japanese tsunami in March 2011.

If you often import and export walking, hiking, biking or similar routes, you may prefer the Trails – GPS Tracker app (iPhone only, $4), which lets you import a trail that a friend has recorded (provided you both have the app). It's one of many such apps, but it has the highest number of high user ratings.

If all you want is to remember the places that you’ve been, Google Latitude (Android, iPhone, free) is worth a look. It works similarly to RunKeeper (though it's not as precise) by automatically recording your route on a Google Map, viewable by checking your “location history”. Unlike RunKeeper, Google Latitude lets you “check in” to particular landmarks and attractions. Later on, you can create an overview of your journey by reviewing the places where you checked in and adding favourites to a customized map.

As an added bonus, all of the above apps give you the option to keep your travel history private.

Sean O'Neill is the tech travel columnist for BBC Travel