Rain stops play

Yesterday we had warning that it was going to rain in the early afternoon, but we went out anyway.  We managed a 40x40m block of GPR data and all the annoying partials around the end of the hedgerow with the magnetometer.  Then, in the early afternoon, it started to drizzle.  Luckily we decided to head home as later it really started to rain.  Today has also been washed out.  We’ve had 31mm of rain in the last 24 hours.

The break has, however, enabled me to catch up on some data processing, especially with the GPR.  Firstly, we can see how much we have done so far.

The magnetometry survey after day 13.

The magnetometry survey after day 13.

As can be seen, we have already covered a good sized area of the theatre field.  Still quite a bit to do, however, and the weather forecast is looking a little grim.

Zooming into the area we are working on at the moment…

Mag survey near the hedgerow.

Mag survey near the hedgerow.

We have a part of the SW-NE road (street 25 in Niblett and Thompson 2005) and buildings alongside it.  It looks like we have buildings around the outside edges of Insula XXX and a quite open area in the middle.

The rain has given me a bit of time to work on the GPR results.  Here is the overall plot. Please remember this is a simple mash-up in Google Earth and that I should be able to get much better plots eventually.

All the GPR results up to day 13 plotted together in Google Earth.

All the GPR results up to day 13 plotted together in Google Earth.

The same area as before without the GPR data.

The same area as before without the GPR data.

If you compare the mag and GPR data you can see that some features that look like walls in the mag data show clearly in the GPR data, but some show as faint negative (light) areas. This is probably the difference between buildings which have had their footings robbed and those where they survive.  The temple does not show very clearly in either data set.  It seems likely it was badly robbed.

The area surveyed on days 12 and 13 is especially interesting.

The block of GPR data collected on days 12 and 13.

The block of GPR data collected on days 12 and 13.

The same area with just the mag image.

The same area with just the mag image.

The corridor building shows very well, but the sinuous ditch is conspicuous by its absence.

Hopefully the rain will let up long enough for us to manage a little more survey tomorrow.

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