Aerial survey of land and sites around Seaton

A standard survey grid points the camera straight down, which is right for ground and useless for a vertical face: a cliff photographed from directly above shows the top of it and a shadow. Capturing a face means flying obliques along it, at a consistent stand-off, with the camera angled in.

That is a different flight, planned differently and priced differently, and on this coast it is asked for regularly. Where both are wanted, the ground above and the face below, that is two captures combined into one model rather than one flight doing both.

The coast west of the Axe is landslip country, some of the most active in England, where whole blocks of ground have moved and are still moving under thick woodland cover. Ground like that is only interesting as a sequence.

So the useful product here is repeat capture on a fixed plan, with the differences between visits doing the talking. The complication is the tree cover: under a closed canopy the model reads the tops of the trees, not the slipped ground, and the plain position is that the parts under full crown are not measured. Winter helps. It does not solve it.

East of the town the Axe opens into estuary and wetland, with reedbed, grazing marsh, ditches and water levels that are managed as well as tidal. What a survey can show there is extent, vegetation, ditch networks, water on the day and how those change across a year.

What it cannot show is anything under the water, and on marsh ground that is a large share of the surface for much of the winter. A wetland capture is therefore booked for the state of the ground you want on record, and the report states the tide and the water level at the time rather than leaving the reader to guess.

The stone workings in this parish are old and partly underground, and underground is where a camera stops. What an aerial survey covers is the surface expression: the entrance areas, the spoil, the overlying ground, subsidence hollows and vegetation change, all of which are reasonable subjects for a dated record.

Anything about the void beneath is somebody else's instrument and somebody else's report. Saying so plainly is more useful than a survey that quietly implies it has seen ground it has not.

The town faces directly south with the beach a few metres from the front row of buildings, and there is little between it and the Channel. Onshore wind and spray shorten the number of usable days on this stretch, and salt film on a lens quietly softens a whole set of frames.

The remedy is unglamorous: work out of the vehicle, check the glass between flights, and be willing to move the date rather than hand over a soft capture that nobody notices is soft until they try to measure off it.