Greetings,
I am using laser theodolite and GPS to collect field data for years now and
the speed and accuracy to gather data points is unbeatable. The model of
the laser is a Seikosha Set 4B with a data logger and the SDRmap software
on a PC. The GPS is a Trimble ProXL used as a differential GPS using the
base stations either of the Department of Survey and Land Information or
the Geography Department at the University of Auckland.
The uneasiness of some archaeologists towards modern survey equipment,
expressed in an e-mail of Ned Heite, may be caused by the amateurish
attitude still reigning large parts of archaeology. It is the same
uneasiness often expressed towards theoretical approaches to archaeolology.
What are the methodical requirements of a site survey? A site survey breaks
down into four steps:
1. Fixing your position independant from landmarks, expressing it in
Coordinates and Height.
2. Recording all elements of the site in their position to each other and
the surrounding landscape. An element is everything which indicates a
man-made change to the natural landscape (terraces, trenches, stone
scatter, etc.).
3. Interpretating the archaeological meaning and value of these elements.
4. Interpretating the site type, based on its elements.
There are two distinctive methodical differences in this four step process:
Recording <-> Interpretating.
Land surveyors are faced with the same problem. They have to position
different things/elements in the landscape. Therfore they devised programms
for the laser theodolite to code streets, offsets of streets, manholes,
lampposts, etc. Each one of the codes indicates something different and has
its own linetype or symbol on the finished map. I have used and changed
this coding system for the specific requirements of archaeological mapping
on the North Island, NZ (SDRmap software). Using the laser theodolite or
the GPS each point has coordinates and height as well as a code, indicating
my archaeological interpretation of the element to which this point
belongs. The software on the finished map draws either symbols or specific
lines which translate my interpretation into a map with a key. In addition
to recording the elements of a site and their position to each other and
the map grid I usually take additional points important to the micro
landscape surrounding the site. All points are then used to develop a
Digital Elevation Model, which can be used to show the position of the site
as part of the landscape(elevation lines, 20 cm spacing). The
interpretation of the site can be enhanced by producing a 3D model of the
site based on the DEM (this is a simple process, once you collected the
data for the DEM).
The speed and accuracay to produce a publishable archaeological map of the
site can never be achieved by using tape, compass and clinometer to draw a
field sketch which then has to be reproduced in ink.
I learned to use theodolites with the German army and with the right
preparation and handling of the electronic equipment, it is possible to run
these instruments in near blizzard conditions (as long as you can still see
something). There are watertight laptop computers around - I can give you
the contact in NZ; they are using the computers on the America's Cup
yachts.
The moment you clarified the methodical approach and theoretical aim of the
site recording, the used equipment - manual or electronic - does not make
any huge difference in the results. After gaining the skills to use
electronic equipment, the advantages of accuracy and speed are undeniable.
The downside are higher costs. But by renting electronic equipment instead
of buying, quite often the renting costs are less than the time/costs
gained in the field.
Please do not hesitate to contact me, if you have any further questions or
if you need examples, etc.
Cheers,
Hans
Dr. Hans-Dieter Bader
Distant Worlds - Archaeology and Heritage Management
PO Box 68653, Newton, Auckland, NZ
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