Open Steet Maps

Written by ralph on 25/02/2011. Posted in Kit and Equipment

Using a garmin satnav has distinct advantages.  In normal use UK & Europe the mapping is similar to other units (Tom Tom, etc.).  It’s when you wander off road or beyond Europe that these advantages emerge.

All (I think) Garmin units are pre-loaded with a world base map which provides basic, main road mapping in countries like Tunisia and Morocco.  However this map is extremely basic and, in many cases, inaccurate.  It will give you a rough idea where you are in relation to major towns though.

Another advantage of Garmin units is the fact that many overland travellers have developed more detailed maps which can be downloaded free (or very cheaply) and installed in the device.  For Tunisia I used the Free Tunisia V12 vector Topo and Road Map ( which had many of the desert pistes marked and seemed very accurate.

For Morocco I am going to try something else.  I have discovered the Open Street map project ( which is producing free routable maps for the whole world.  The maps can be downloaded in a garmin compatible format and work in the same way as the maps installed by Garmin.  They can show 2d or 3d, give turn by turn instructions and have a lot more points of interest loaded.  Importantly they are being updated all the time by the map users.  You can even upload tracks yourself.

Norwich_mapAlthough it may be difficult to see, this is a screenshot of the map of central Norwich (my nearest city).  This, hopefully, will give you an idea of the level of detail.  It is almost on a par with Google maps.

I have downloaded the UK maps and used them instead of the pre-installed Garmin maps on my Nuvi 255W and I have not found any difference in their operation.  There are minor variances in colour but, apart from that, you wouldn’t know you were using a free map.

With Garmin updates working out at £60-£75 this is a big bonus.

The main site for downloading the maps is  On here you can select the countries (or part countries) you want, add your email and they will be compiled for you.  It can take a couple of days but you will receive an email with a download link.  From that link you will access your compiled maps which you can load straight into mapsource (to add to you gps) or files to load onto a SD card which you can insert directly into the unit.

File size is important as you need to fit it onto an SD card.  The whole world would be well over 10Gb so it is advisable to only load what you need.  You cannot download more than one map and use them side by side (unless you put them on seperate SD cards) as, regardless of what the map is, the file name is always the same.  So there will be a clash.

I have downloaded the UK, Spain and Morocco into a single map and this is under 400Mb.  I shall do this again just before we go away so that I have the most up to date maps.

The level of detail, especially for countries like Morocco is staggering compared to other available electronic maps.

I am also looking onto the possibility of running these maps on a laptop and having a small screen on the dash rather than the garmin.  I will keep you informed how this goes.

Even if you don’t intend to drive outside areas of normal map coverage this is a much cheaper way of updating the mapping on your garmin gps.

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