Thursday 10 January 2013

Ashby Puerorum

This rather nice cropmark plot appeared in Bewley 1998 Lincolnshire's Archaeology from the Air. Rather less helpfully, it appeared unadorned by anything as useful as NGR reference points (let alone base mapping). It is at least at a handy 1:25000 and individual cropmark complexes are provided with six-figure grid references elsewhere in the volume, so we have somewhere to start. Beyond that it's trying to spot places where the pattern is interrupted by a road line or block of woodland (the cropmarks just north of Bag Enderby do the trick) so as to position them with some confidence (even if only at this small scale). Why? Well, there may be some work on the site at Ashby Puerorum in the northwest corner. Bulldozed in the 1980s to produce embanked stock compounds the question is what, if anything, survives?

Monday 7 January 2013

ASTER + Landsat = Dacia

Up to now I have tended to work with SRTM data for small-medium scale topographic mapping (the topographic base I use for all my UK regional maps starts from there).  It was always somewhat annoying that the rest-of-the-world dataset was less detailed than that available for the US... which is where ASTER comes in. Version 2 of the dataset has been out for over a year now and I must admit its taken me this long to really get round to looking at it. I like what I see. [But in some lower relief areas - and particularly the UK - it leaves a lot to be desired. Really no better than SRTM - see the useful comments here.]
The above uses ASTER elevation data for topographic mapping with a Landsat overlay to give some realistic colouration. The approach routes of the Roman armies to the Dacian fortress at Sarmizegetusa are taken from Stefan 1998. The grid squares are 5km.