Yet the Berkeley archaeologists lacked
two critical pieces of information for establishing a long-term
excavation at the site. First of all, the team was without any
real-world data for the elevation of points on the tell.
Secondly, there was no way of consistently locating the features and
objects found in the different areas of the site.
Setting GPS benchmark in limestone
outcrop. Note "X" on face of rock used as a datum for the 1980
Thus, the team started the first year
by establishing a number benchmarks in a variety of locations around
the tell. In 2001 seven different locations were identified
where the limestone bedrock appeared at the surface. At each of
these locations a brass pin was permanently secured to the stone.
Next, using differential GPS and a series of lengthy data collection
sessions, a secure network was established which connected all of
these points to one another. Using this data the global location
and elevation was determined for each of the seven benchmarks.
Working from these benchmarks, the team could now determine the
precise elevation of any point atop the tell. The first problem
had been solved.
(left) Brass pin at location of
Benchmark 01. (right) GPS survey to determine location of
Considering its incredible accuracy,
the Berkeley archaeologists could certainly have used GPS to determine
the location of artifacts and features discovered through excavation
or in surface surveys anywhere in the area. However, this method
of mapping finds required the constant use of computer calculations
and processing. Furthermore, while precise, the location data
was rather convoluted and prevented an easy comprehension of location.
For example, knowing that Benchmark 01 is located at 3,185,906.789 m
N, 297,100.151m S, and 47.482 m ASL doesn't allow the team to quickly
understand that this datum point is located in the southernmost part
of the tell, just south of the temple temenos.
Kinematic survey is useful for exact
locations, but helps little with rough estimates of location.