The survey methodology was designed to achieve 100% coverage of the project area. Recent advances in computer software allowed the survey crew to have daily generated maps of what they covered and which areas needed further documentation. Water resistant notebooks were used to record the data and accompanying field sketches.
The survey instrument, a Topcon GTS2R, records data points by bouncing light off a movable prism. The prism is placed in a desired location and the instrument records its position in reference to its own. Locations where the instrument was set up were given individual station numbers and marked with a small piece of rebar. Each new station was established by sighting it from the prior station. The crew moved the instrument in loops of stations, regularly returning to previously established locations in order to monitor and control the accumulation of error. The data entered from the survey was recorded as three dimensional points, one for each shot taken in the field. Those 3-D points were then manipulated in Foresight, a professional survey software package, to create a map of contour lines and structure footprints. This process allowed the map to be field checked as it was generated, ensuring accuracy and completeness. At the conclusion of the season, the Foresight file was transferred to AutoCAD, computer aided drafting software, and combined with digital architectural drawings to create the final maps. A coordinate grid begun in the 1998 season will be expanded as the survey continues out. The grid's point of origin, designated 8000N, 8000E, is located on the west side of the Temple of the Cross. Its location was chosen to link with a small grid of bench marks placed in the Cross Group by INAH archaeologist Rosalva Nieto in the 1980's.
New bench marks have been and will continue to be placed in outlying groups as an aid to future investigations at Palenque.
Each structure encountered during survey must be given a designation. In the case of Palenque, this presents a methodological problem. The major structures of the site already have designations, mostly roman numeral. The groups of the periphery, however, were named during different project resulting in a mixing of designation systems. Some groups have received more than one designation, creating confusion in the literature. The task of the PMP is to use a designation system that does not require changing existing names and at the same time builds upon an existing system. It was decided that going with the oldest, most expansive designation system is the best solution. The first project to map Palenque's periphery was in the 1920's, conducted by Franz Blom. His system was to identify peripheral structures in groups, giving each an alphabetic designation. Eventually, they became known as Blom's Groups A through J. The PMP chose to build from the Blom's Group system, designating each structure with a letter reflecting its group affiliation and a number individualizing it within the group. For outer groups Blom did not designate, the group name given in the Robertson map (1983) was used, or, if the group had not been previously recorded, a new group name was designated. Where appropriate, Blom's alphabetic system will be continued beginning with his last letter. |