Map reading for beginners.

Maps do not of course come value free. That is to say that they are social products and as such are not only representations of the world but reflections of the ideas and aspirations of the map maker as well. I suppose that maps have played a far more important role in my life than they do for most people. Marine charts were a tool of the trade for much of my working life but even a day out is not complete for me without a map and at least some understanding of the local topography. But even for someone pretty clued up about maps and map making it's easy to fall into the trap of accepting the map as in some way "true". Cartographers have to make a huge number of decisions about what to include and what to leave out of a map as well as where to centre it and what projection to use and these decisions both reflect the map makers world view - and go toward shaping our own as well. If you doubt this just think back to the school atlas hanging on the classroom wall. The distortions of the classic Mercator projection give the impression that Europe and our tiny island are huge in comparison with equatorial countries and this combined with centring the map on the Greenwich Meridian ensured Britain's central position in the world for generations of schoolkids. On such assumptions an empire was consolidated.
In an effort to encourage Londoners to walk to work during the Olympics and ease the pressure on what will be a hopelessly overburdened transport system, TfL and Mayor for London have published a map displaying the walking times from Fenchurch Street Station.  Concentric circles radiate out from Fenchurch Street so we can see for example that both Bank and Liverpool Street are within the ten minute  radius, Tate Modern is within the fifteen to twenty minute zone and that Colombia Road Flower Market is way out on the twenty five minute line. It's a practical map and pleasing to the eye as well; but take a closer look. The map is not actually centred on Fenchurch Street but somewhere near Guildhall and this means that the distance rings come to an abrupt halt on the southern and eastern edges of the sheet. By situating places like Stepney and Walworth  beyond the pale, in some kind of City Hall terra incognita, we are given a distorted view of London and an insight into the thinking of those who run the capital as well. You can learn a lot from maps - and sometimes find more than just your way from A to B.