Monday 21 April 2014

„@MAP“ the Arc-Team Mobile Mapping Platform

In Summer 2013 Arc-Team was charged with the task to survey a micro-DTM on an archaeological area of about 10.000 m2.
The underlying archaeological remains on the side cause small differences in height on the surface and the shape of a nearly 60 x 60 meters large structure was known from aerial photographs.

We've had only 10 hours of fieldwork at our disposal and exploring our options we've made some numbers games:
  • Doing the job with total station would allow us to take an average of 5 points per minute, which means a (very optimistic) total amount of 3000 points in 10 hours. (2 operators)

  • Using our DGPS, the stroke per minute increases up to a maximum of 15 points per minute, working with continuous point capturing mode, having an operator on the field who's stepping forward, putting down the pole and balancing the bubble eyery 4 seconds. The total amount in this case is about 9000 points. This means an average of only 0,9 points / m2. That would be far to few...

So what would we going to do?

In this occasion we've had the idea to adapt a monocycle in order to have a rollable vehicle carrying the GPS antenna and maintaining a constant distance to the ground.
The result you can admire in the illustration below.

By the help of this tool we were able to increase the stroke on 42 points / minute and a total amount of almost 25.000 points. This means an average of at least 2,5 points / m2.

The result of our efforts was quite lovely: GRASS GIS produced a high quality DTM from which we derive 3D views, isolines and shaded reliefs.

The official name of the trolley is „@MAP“ Arc-Team Mobile Mapping Platform. ;-)

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