How big is that hole? Drones investigate..
Our Director of Technological Solutions, Dr Peter Rauxloh, explains the importance of using drones to accurately measure and monitor in archaeology.
Archaeologists are of course very interested in digging holes, and carefully recording the size of those holes and the features they discover within them. Keeping an eye on how much excavation has occurred, is as important for us as it is for the people we work for, since it provides information on the rate of work, how much has been done, how much is left and how much post-excavation work is likely. An archaeological project, like any business, has to balance it’s resources, so the project may be properly completed to the satisfaction of all.
The question of just how much excavation has been carried out, can be answered in a number of ways:
- A site will have a foot print and the rough dimensions of that foot print will provide us with a an area.
- If we then multiply the area by the average depth, we obtain a volume – primary school mathematics is great!
However, things get more complicated when the shape of the area is more complex, and the bottom of the hole is anything but flat. For example, if we wish to determine the volume of material that has been removed by erosion - perhaps a coastal site that is nibbled by the sea – we really need to be more precise.
In these situations we need to consider two surfaces; a before surface and an after surface. If you imagine a box with a lid, the before surface is the top of the lid, the after surface is the bottom of the box, after the lid has been removed. If that lid was covered with a grid of squares, you could ask of each square, how far is it above the bottom of the box? By adding up the answers from every square and multiplying by the size of a square, we get a volume. This simple principle also works where the sides of our box are not straight, and neither the lid or bottom of the box, is flat. The challenge is to accurately create these two surfaces.
