The Edge 800 is the top of Garmin's dedicated bike GPS device range and has the capability of guiding you around the trails. In order to navigate using this beastie though, you have a few options on how much detail you can get out of the mapping. Some of the options are better then others but price tends to be the great leveler here. There are a few ways around it though.

So here are a few of the options available to you!

Standard Base Maps
The Edge 800 is a pricey bit of tech and at £349.99 you may well be tempted to put up with what comes included in the basic package. The base maps do provide key roads so to an extent could be used for road riding. As soon as you want to go off the beaten track though, the base maps become pretty useless.

So can you get away with just the base maps? The answer is yes if you are just going to download routes to the device and engage in follow the line navigation. Don't expect to get out an explore the landscape though, you will need to do this before hand when you are plotting your route at home.

With a device like the Edge 800, you really do want to take advantage of the screen. If you are just hoping to stick with the base maps you are probably better off saving some money and getting an Edge 605 or 705.

Garmin GB Discoverer Maps
For £50 over the cost of the basic package at £399.99, Garmin do a 'Trail Bundle' which includes their GB Discoverer 1:50,000 Maps which offer full UK coverage to Ordnance Survey standard. As you would expect, this will give you sight of footpaths, bridleways and byways as well as contour lines and local points of interest. This means you get all the detail you would ever want whilst out and about allowing you to go and explore on the fly. £50 sounds like a lot but the GB Discoverer maps on their own retail at £119.99 and electronic mapping is generally very expensive. Take for example memory map, you will pay £50 for just one region of the UK!

Custom Maps
So is there a middle ground? Free maps which are detailed enough to allow you to navigate on the fly if you find yourself needing to deviate from a planned route? The answer is yeas and can be found with the ability to add custom maps to the Edge 800.

By using one of the many mapping tools available online, you can create maps and save them in the Garmin Custom Map format (KMZ). These can then be dropped into a specific folder location on the device allowing an option to use the maps on the device. You can then switch off the base maps and switch on your custom maps thus allowing you greater control over how much detail you have available.

You will probably need a micro SD card to do this as map tiles do tend to take up a lot of space on the device.

Installing Custom Maps
So here's a 10 step guide to installing a custom map onto your Edge 800 using Atlas Creator.

Step 1: Download Atlas Creator and unzip it.
Step 2: Open 'Mobile Atlas Creator.exe' (Mobile_Atlas_Creator.jar on a Mac)
Step 3: Select the type of map you want to create
Step 4: In SETTINGS select MAP SIZE tab, enter 1024 for max map size and in the DIRECTORIES tab enter the output directory where you want to save your map.
Step 5: Select Garmin Custom Map (KMZ) under ATLAS SETTINGS
Step 6: Hold mouse right click and drag to move map. Hold mouse left click to select the area
Step 7: Select desired Zoom level checkbox, (14 usually good for the Edge's screen resolution but have a play about with this)
Step 8: NAME your Atlas press clear then ADD SELECTION. Click CREATE ATLAS.
Step 9: Copy the KMZ file that you just created to your micro SD card in the directory 'Garmin\CustomMaps'
Step 10: Put the SD card into your Edge 800 and boot it up. Your maps should now be available. If you can't see then go to Settings>System>Map>Map Information and make sure custom maps are enabled. You may also wish to disable the base maps.

There are a whole range of maps available in that version of Atlas Creator, some of which probably shouldn't be there. Just be aware of this and choose your maps responsibly. There are plenty to choose from!

The Edge series of GPS devices are all great for pre-plotted follow the line route navigation so as long as everything goes to plan the base maps provided will usually do the trick. You should remember that the Edge series is not a dedicated navigation device but in fact a multi-function, GPS enabled bike computer and training device. If you do need to deviate from your expected route then the Edge 800 with its ability to display more detailed maps comes into its own. It is on par with the Dakota range in this respect and can be used quite effectively for getting yourself out of a spot.

What it isn't though is an out and out go and explore device. For me the screen is to small for that. You will soon get bored of trying to scroll around to find out where you are and where you need to be. There are other devices in the Garmin range that would be more suitable for a biking adventure!

So how much detail do you really need? For 90% of the time OpenStreetMaps would suffice and they are free using the custom mapping technique above. For the other 10% of the time the GB Discoverer Maps are king. You just need to decide if that 10% is worth the extra £50!