Changes afoot on Ordnance Survey paper maps and a useful reminder of the importance of Datums!

You may never have noticed, but there are feint markings along the margins of Ordnance Survey paper maps. These represent not the OS grid with which we are familiar and most spatial references in the UK still use (eg. NT 123 456) but rather a latitude-longitude grid.  This system is more international than the GB grid, which is just effective over the local area of our small islands.  The current lat-long grid uses the Airy 1830 ellipsoid/datum, and the OS are proposing replacing this with the WGS84 datum to give compatibility with the GPS system.  This reminds us that lat-long references (or indeed any grid-based spatial reference) is only unique when its datum is specified. Its no use just quoting:

55.9294° N,  3.1642° W

without the datum that could represent different places.

So what does Ordnance Survey’s change mean?  Well it means any lat-long references taken from the paper map (probably fairly unlikely) will now be wrong – actually not wrong just in need of conversion to the different datum. The OS say that for “Landranger Maps, this movement may be as little as 2mm.”  That’s 100m on the ground.  They don’t give a maximum error. Further details are here

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38 Maps that explain Europe

As a lover of maps, I came across a genglish-eureat web site which uses cartography to perfectly describe what geography is all about – the linkages between place, people, history and culture, and natural resource: 38 Maps that explain Europe.  Its an American site, so perhaps a rather American view of Europe, but interesting never-the-less.  If you think you know of a map which should be there, please add it via a comment to this post.  There are also sister-sites which include 40 maps that explain World War I and 40 maps that explain the Middle East.

 

New Year – New Students

A new university year begins with a healthy intake of students into the four degree programmes which now comprise our GIS cluster; namely GIS (taught), GIS (research), GIS & Archaeology and our new Earth Observation & Geoinformation Management programme. With last year’s students having finished a few weeks ago and now actively gaining employment, we have thirty new students in these programmes.  Keeping ahead, changes include a new course on Business Geographics.