Even if you're familiar with Google Maps and Google Earth, you might not realise how much these free mapping services offer. Here are 10 useful features you should know about.

1. Google Maps isn’t Google’s only mapping product. Google Earth isn’t as popular but if offers many features you won’t find in Google Maps. Although Google Earth accesses online data, you first need to download the Google Earth application from earth.google.co.uk.

2. Because it uses software on your own PC, Google Earth offers a more polished interface than Google Maps as you’ll quickly discover (you can, however switch to Goole Earth in your browser by clicking the Earth button at the top-right corner in Google Maps). The emphasis is on satellite imagery, as opposed to road maps but, unlike Google Maps, it allows you to explore the Earth’s polar regions, and even the Moon and Mars.

3. No doubt you’ve used Google Maps Street View feature but did you know it works in 3D? To turn on 3D, press 3 or T. Red and cyan fringes will appear on the image but if you put on a pair of red-cyan glasses (e.g. from www.assistpoint.co.uk), you’ll the scene in 3D. Note that you can't enable 3D if you're using the MapsGL mode.

3D Street View Google Maps

4. Google Earth includes a flight simulator so that you can view the Earth from a unique perspective. Just select “Enter Flight Simulator” from the Tools menu and then select your aircraft of choice and a starting location. You’re not likely to have much success without understanding the controls so remember that you can press Ctrl-H at any time to see the flight simulator’s help screen.

5. Thought that Google Maps was just for exploring the surface of the Earth? Well you can now journey below the surface as Google Maps’ Street View now includes two underground locations. Check out the Akiyoshi-do caves in Japan. With parts of the Amazon rain forest included too, the term Street View, seems less appropriate than ever.

Google Street View caves

6. Google Maps can show up-to-the-minute traffic conditions in many part of the UK. Click on the white box labelled Traffic in the top-right corner of the map and click on traffic in the pull-down menu (there are other options here you may find interesting too). Roads will be coloured according to how well traffic is currently flowing.

7. Don’t think of Google Maps as a universal panacea because there are some places you can’t see. In North Korea, for example you don’t have access to detailed maps, although you can see just a few roads and low-resolution satellite imagery. There are some places in the West you can’t see in detail too – try this for example.

Google Maps Noordwijk

8. If you’re an Android user you’ve probably discovered the Google Maps app but you might not have realised that it can be used offline too. Normally, of course, you receive the map data via Wi-Fi or 3G but if you travel in out-of-the-way places, you might find yourself with no network coverage. If you anticipate this eventuality, though, you can download the relevant portion of the map before you go (tap the menu button in Maps and choose 'Make available offline'.

Google Maps Android Offline

9. Using Google Maps doesn’t have to be a passive experience. You can define your own points of interest or routes, together with descriptions and photographs, that others can see superimposed on the map. Take a look at Create and Share Custom Google Maps to see how to do it. Also, you can now submit corrections and add information with Google Map Maker (http://www.google.com/mapmaker)

Google Map Maker

10. You can even create your own 3D models of buildings to view in Google Maps or Google Earth using either SketchUp or Building Maker. If you fancy trying your hand at this, Your World in 3D should be your first port of call.