The Field Report for 1999

Introduction to El Pilar 1999

The BRASS/El Pilar Program is more than an archaeological research program.  Building on the long-term study of Maya settlement, the program's look at the community center of El Pilar in 1993 signaled a new focus.  To consider the monuments of El Pilar required a fresh approach.  The archaeologist wished for preservation, the ecologist wished for conservation, and the Mesoamericanist saw that the heritage values.  El Pilar provides an opportunity to address it all. 

The collective expectations for El Pilar have evolved from a simple wish to look at all of El Pilar.  A major Maya site demands government protection and  investment in community participation. Building from the archeological research, we have gathered in a terrific group of partners for the integrated conservation enterprise of El Pilar. Together, we are designing a model and the steady successes are pointing the team to the right track.

The year 1999 marked great strides in the goals of the El Pilar Program.  The development of the reserve now includes institutionalized relationships among different parts:  the government managers, the community stakeholders, and the research scientists.  This institutional threshold was accomplished by remarkable teamwork of a consortium of partners locally, regionally, and around the globe. 

Deliberate and measured paces have remarkably transformed El Pilar from a concept into a plan. Working with Help for Progress has made Amigos de El Pilar (AdEP) a truly strong community group with a collective voice and defined goals.

Strategic development has moved El Pilar forward because of visionary representation by Anselmo Casteñeda and the careful planning by Help for Progress' director Elias Awe.  Together they crafted a small grant with the US Agency for International Development that leveraged support from Canada Fund to forge cross border community ties in the Maya forest. Collaboratively, we also coordinated the development of the Masewal Gorest Garden and the new comfort stations at El Pilar with Help for Progress and British High Commission. In addition, the Protected Area Technical Evaluation Team worked with the Draft Management Plan for El Pilar, revising and creating a comprehensive plan for implementation at El Pilar.  

At El Pilar, we have cast our image.  No exposed temple-like the Castillo at Chichen for El Pilar. The Tzunu'n Maya house and forest garden is open to the public. This signature of the human component is not lost on the international public.  This years Fodor's , called by The New Yorker the premier travel companion, says:

…… At El Pilar, the emphasis is on domestic architecture-reconstructing houses, replanting a garden with crops used by the ancient Maya, and generally creating a sense that people actually lived here. …[W]ell-marked trails take you around the site. Because the structures have not been stripped of vegetation, you may feel like you're walking through a series of shady orchards …..

It has been exciting to witness the transformation of the house site at Tzunu'un from housemounds to an excavation to a destination. The architectural features we have exposed over the past several years have helped to envision the result.  We carefully collected artifacts from the structural remains and we meticulously drew up detailed plans of the site before we could approach the presentation. 

This year was the push to share our findings with the greater public locally, regionally, and internationally.  While stabilizing the final parts of the walls and floors of the main building, we constructed thatch structures over two excavated wall foundations.  We knew that the buildings of Tzunu'un were large, after all it was one of the grandest residential groups recorded in the surveys.  Yet, when we constructed the pole-and-thatch buildings over them, it changed the view. Then, when we took off the old provisional protective roof of the range structure, the whole area took on a new aspect.  Impressive, compelling, real.

A visit to the site reveals the success of our seasons of labor.  The house structures are comfortably situated within the flourishing forest garden, inviting discovery on the El Pilar trails. El Pilar can be a model for a new way to explore the past.

>Aims of the season

Mapping

                The El Pilar Archaeological Mapping Project focused on the survey coordination and development.  The main objective was to verify the El Pilar site grid and transform the local grid into the UTM (Universal Transverse Macerator) grid system used by the Land Information Center of Belize.  This effort involved the use of the full-station transit in the terrestrial survey of control points and the strategic use of using GPS (Global Positioning System) to adjust the references in the old grid to UTM. The use of the UTM system at El Pilar will make the data collection, inventories and infrastructure planning part of a Geographic Information System (GIS), effectively part of the system developed and used in Belize.  The data we gather for El Pilar can readily be incorporated into the larger GIS systems, including the UCSB Maya Forest GIS.  The UCSB Maya Forest GIS has the potential to compile and manage Maya archaeological data form the more general center locations, to the most specific excavation data. 

Tzunu'n: The Maya House

The mayor objective of 1999 field season was to complete the first stage of investigations at Tzunu'n and prepare it for presentation to the general public. The archaeological investigation incorporated confirming the method of access from plaza into Str 1, clarifying the construction chronology and building sequences of this residential range building.  In addition, the examination of Str. 2 verified its classification as a temple or shrine by completing examination of looter's trench. The superstructure remains were detailed, and evidence of construction developments identified.  The complex excavation data suggest that the area was under a final renovation at the time of abandonment.   

In order to present the plaza group in an interpretable manner, understandable to the general public, experimental procedures from 1998 were evaluated and incorporated into the 1999 consolidations. To increase the ease of interpretation by the average visitor, two of the smaller structures were covered with roofs in traditional Maya style. The third structure was exposed to view, consolidated in the open, in order to display to the general public the variety of remains from which archaeologists draw their conclusions.

Forest Garden

Work at the forest garden continued with the collaboration of AdEP and the caretakers at El Pilar.  We have monitored growth and development in the forest garden at Tzunu'un and learned from the Caretaker House garden.  In addition, links with Heriberto Cocom's new Masewal Forest Garden Trail promise to create new links to traditional farming methods.

Some of the issues at the forest garden concern planning.  Light and shade clearly affects the success or failure of some growth.  We conducted an examination of the forest garden floor with respect to the amount of sunlight reaching through the canopy.  This will assist in planning future plantings. We also developed a first draft of a Tzunu'un Forest Garden Trail that features common forest trees and herbs.  This will soon be assembled into a resource for El Pilar. 

Community Participation

                An ongoing and important aspect of the BRASS/El Pilar Program is the work with the community.  The focus of the 1999 field season was to increase the awareness of different Maya tour destinations to inspire feedback on community goals for El Pilar Archaeological Reserve for Maya Flora and Fauna (EPAR) preservation and display.  We also worked with Help for Progress in planning and developing the linkages that will fortify the community involvement in El Pilar.

Summary

This report documents the integrated conservation efforts that we envision for El Pilar.  Our accomplishments and experience are at the foundation of a new model for conservation in the Maya forest.

THE EL PILAR ARCHAEOLOGICAL MAPPING PROJECT

The spatial data collected and recorded for El Pilar are compiled from a variety of sources: BRASS/El Pilar Program, interdisciplinary research data from ecology, agriculture, landscape-architecture, etc., government, universities, and other public domain arenas. These data are destined for integration in the UCSB Maya Forest GIS and are the basis of the El Pilar Archaeological Mapping Project, headed by William Poe of Sonoma State University, California.  The data are generally organized into 1) the El Pilar Archaeological Reserve (EPAR ) area and 2) the archaeological surveys and excavations.

The essential bases of the mapping in BRASS / El Pilar Program are:

·         the development of a local control points network at El Pilar between 1984 and 1993 to locate the survey and excavations areas,

·         the establishment of boundary benchmarks by Cayo District Lands and Survey in definition of the El Pilar Archaeological Reserve (EPAR) in 1995,

·         the initiation of the El Pilar Archaeological Mapping Project with W. Poe of Sonoma State University in 1997,

·         the coordination of a UCSB Maya Forest Geographic Information System (GIS) in conjunction with the Geography Department, University of California, Santa Barbara in 1998.

The Reference Network

A local control point network was established in 1993 around the civic center El Pilar and has been used for all mapping exercises at the site. Independent research operations proceed on a local grid network linked to control points within the site. The control point network serves as the central reference.  In 1995, a controlled survey of the EPAR reserve boundaries was executed and provided a basis for linking the local control points at El Pilar and the international Universal Tranverse Mercator (UTM) grid system. The 1999 season was designed to unify the El Pilar mapping data onto one comprehensive system.  This involved transforming the local control point network to the UTM network.

The Local Control Point Network

The local control point network is based on the Geodetic Elevation Marker E10 located in the site. The coordinates of E10 were set to 0, 0, 232 m Mean Sea Level (MSL). In 1993, the network was oriented by magnetic north as the bearing 0°.  Control points at El Pilar were set up step by step over the years, by different surveyors, following the site clearing and excavations. The development of the composite control point network across the 40-hectares of site core was individual and resulted in a mosaic with accumulated survey errors over the years of accretion.  The whole network had not been adjusted between surveyors and consequently there would be some compromise expected in the reliability of the network as a whole.  Consequently, a critical objective of the 1999 season was to regularize the local El Pilar control point network and unite it with the EPAR boundary survey by transforming the local grid to the UTM grid.  The objective was to firmly establish critical ground controls for the basic research data and facilitate the data integration into the GIS.

The UTM Grid

In order to link the El Pilar site to a world projection system, the local network had to be transformed to universal system. The EPAR location had been defined based on one permanent Belizean reference point: SBM1. From this UTM grid benchmark, a survey line was extended to the E c. 2.1 km to the SE corner of the EPAR, from there N c. 2.9 km to the NE corner, and from there WNW to the Belize border.

Our interpretation of the Statutory Instrument (No. 54 of 1998) gives the established physical boundary coordinates of the EPAR as follows:

From the western border of Belize to:

(UTM, Zone 16, Datum NAD27 Central America)

Bearing 279 °08'15" from the North East corner to the western border of Belize

To confirm the location of the EPAR trapezoid and to develop the linkage of the EPAR boundaries to the local El Pilar control point network, a GPS method was employed based on the single reference benchmark SBM1. While the GPS is the best strategy, the Maya forest canopy presented difficulties.

Boundary and Corner Marker Survey

The monuments established to mark the physical boundary of EPAR were occupied using a rapid static GPS survey technique. This required walking the length of the boundary and locating each of the existing benchmarks. Each benchmark was then occupied with the GPS to establish the coordinates. These data were collected under different conditions and different methods. All the data were differentially corrected in the lab. The GPS data were compared with the legal description in the Statutory Instrument.

Mapping Assumptions

The legal description of the El Pilar Archaeological Reserve for Maya Flora and Fauna defines the UTM coordinates of the South Boundary Marker, SBM1, as 907180N/

271933 E as determined by the Cayo Survey Department traverse and a solar observation on 24 February 1995. The coordinates of SBM1 are only available to the closest meter and the elevation of SBM1 is not available.

Point E10 is a bronze marker set in a concrete base. The medallion is inscribed “Interamerican Geodetic Survey 1962”. The horizontal location of E10 is not available. Site records indicate that Field notes of the Ministry of Natural Resources, Belize, define the elevation (MSL) of E10 as 231.77 m.  The horizontal coordinates of SBM1 and the vertical coordinate of E10 are the assumed truths of the El Pilar Archaeological Mapping Project. Program Geomag determined the site magnetic declination at that date as 2° 44.7'. This program file is available to the public from the WWW server of the World Data Center at  http://www.ngdc.noaa.gov/seg/potfld/geomag.html

Base Station Reference Position

The base station position was a monument placed by A. Girardin on the northeast corner of the cement platform that supports the water tank at the caretaker's cottage and is referred to as EPB1. The 1998 base station position had been a temporary location, with the base station antenna mast attached to a PVC pipe on the western side of the water tank.

The base station reference position was determined by placing the base station at the known station of SBM1 (1907180 N / 271933 E) and recording 1243 positions at 5-second intervals with the rover at the base station monument. This resulted in the following GPS determination of the base station reference position. (26 May 1999)

Terrestrial Data

A total station survey of the El Pilar local control point network was surveyed in the main plaza of El Pilar: Plazas Axcanan, Copal, Duende, Faisan, Ixim, Lec and Tzunu'un. The total station survey occupied monuments at the following twenty-eight established local control points: A2, A3, A5, A6, A9, BL_BM, C1, C5, C6, C7, C8, E10, F1, I3, L1, MB, NB, N1, N2, N4, N5, N7, N10, N11, N14, TN5, TN8, TN10. In order to provide appropriate backsights for future mapping work, the total station team established new monuments in Plaza Faisan, F2, and in Plaza Lec, L2. We also established a monument, EPB1, on the platform at the water tower next to the caretakers' cottage. This point is used as the principal location of the GPS base station.

Thirty temporary stations were occupied as needed during the course of the survey. In addition, stations T1 through T26 were established where lines of sight between control points were lacking. Stations POS1 and POS2 were established as offsets to point E10 to facilitate the location of E10 through GPS survey. Point E10 is overshadowed by trees and while GPS data was recorded on the position, it was not to the desired degree of precision (Appendix #). POS1 and POS2 were located in positions of clear sky and their relationship to E10 was defined by the total station. Similarly, L1 Offset was used as a GPS station because of the difficulty of occupying L1. Stations POS3 through POS5 were used in surveying a transect from E10 to EPB1 to determine the elevation difference between E10 and EPB1.

Satellite Data

A Trimble 4000SE GIS Surveyor was used as the GPS base station. Trimble 12-channel GPS Pathfinder Pro XL receivers with TDC1 Dataloggers were used as rovers. The receivers were set to record carrier data at five-second intervals synchronized with the base station. Data was gathered in static occupations at control points and temporary points where good reception was possible.

Differential Correction

These data were processed by the program GeoGeniusÙ by Spectra Precision Terrasat GmbH, Hoehenkirchen, Germany. This program is designed to integrate terrestrial and satellite data. The program processed the carrier data and produced the results on the baseline measurements in Table 1 below.

In Table 1 the columns headed Rec 1 and Rec 2 identify the two points being simultaneously occupied by two receivers. These are receivers that were recording GPS data simultaneously. Since two rovers were sometimes used, the baseline computed may be between two rovers or between a rover and the base station. The column labeled Epochs indicates the number of common epochs of data, at five-second intervals that exist between the two receivers. This is the number of measurements that will contribute to the average distance calculated between the two receivers. This distance is expressed in meters in the earth-centered earth-fixed WGS84 coordinate system and is recorded in the columns labeled d X, d Y and d Z. The columns labeled s X, s Y and s Z  are the standard deviation of the measurements for each axis and are expressed in millimeters. The column labeled Solutions indicates whether on not the program has been able to fix the best solution within the statistical parameters specified [3] . The L1 indicates that it is a single-frequency solution. The column labeled 2dRMS records two times the root mean square deviation from the averages in millimeters. In a normally distributed data set 95% of the data will lie between -2dRMS and +2dRMS of the average. The full report generated by GeoGenius is appended.

The twenty baselines processed to a fixed solution have a 2dRMS range of 14.6 mm to 40.2 mm with an average of 28.8 mm. This provides sufficient precision to orient the control point network.

TABLE 1: Summary of GPS baseline data