 |
| Tomb |
Guayabo de Turrialba is the most important archeological site in Costa Rica. Flanked to the south by the Turrialba Volcano, the Guayabo Nacional Monumento (1973) is one of those places to visit. Monument’s tropical ambience, atmosphere and mysterious origins make for an amazing if not fascinating experience. The only archaeological park in the country, Guayabo protects the remains of a city that flourished and mysteriously disappeared before the arrival of the Spaniards. Archaeologists deduced that the pre-Columbian city was led by a chief, who exercised political and religious power over a large region. On 2009, it was declared an International Historic Civil Engineering Landmark by the American Society of Civil Engineers when it became a milestone in the engineering world for its water supply and drainage systems, designed to prevent flooding or overflow; after seven centuries of being abandoned are still working.
 |
| General view of the site |
 |
| The monolith of the jaguar and the lizard, whose meaning is still not deciphered. |
Archaeologists are still unclear why this Indian settlement, inhabited by the Cabécar as early as 1000 BC, was abandoned around 1400 AD. Archaeologists believe that this city was a key religious, political and cultural center. The Guayabo National Monument sits on only 10% of its total land area, while the remainder 90% of the land is a premontane rainforest; this 232-hectare monument was first uncovered in 1968 by Carlos Aguilar Piedra, an archeologist at the University of Costa Rica. In the central area of the monument are different mounds with stone foundations, which generally have a circular base of different sizes. It is believed that the houses were build on the mounts with wood and straw, and their high was the diameter of the circular base (up to 30 meters). Excavations have also revealed cobbled roads, a sophisticated city infrastructure, covered and uncovered aqueducts, mysterious petroglyphs, tombs and sculptures, which suggest a highly developed knowledge of civil engineering. Their construction techniques are influenced by both South American and Mesoamerican cultures. Since the American Indians did not use the wheel, many of their streets are equipped with stairs.
 |
| Covered aqueduct |
Who built this lost city? Why did its inhabitants disappear just before the Spanish landed? The most accepted hypothesis mentioned diseases, internal conflicts, maybe even war.
Infrared technology applied to archeology:
 |
| WB-57 was the plane used to taking infrared photographies. |
The results of the research reveal that there were several roads between different human centers all around the country, and the fact that some of those crossed big rivers suggest the existence of bridges. The roads were approximately three meters wide and were constructed to go by feet.
 |
| Infrared picture that shows the Pre-Columbine roads/paths |
The area of Costa Rica has been scanned with various sensors (high resolution visible camera, infra-red camera, MASTER - thermal emission and reflection radiometer etc.) in order to acquire airborne multispectral digital imagery and photographic data for the ecosystem and agricultural research, for urban and land use planning, for studying volcanic activity and hazards, for cartographic purposes and for archeological studies.
Sensors used in multispectral digital photographic imagery: (Main source: NASA Flight Summary Report)
1. Leica RC-30 metric camera is used for natural color imagery with wavelength range 420-700nm mainly for surface mapping and monitoring. Precision photogrammetry and films may be used to generate digital elevation models.
2. Cirrus Digital Camera System (DCS) is used for acquiring flase color infrared imagery with 510-990nm spectral range. Primary use is in habitat mapping and ecosystem monitoring.
3. MODIS/ASTER (MASTER) is the airborne simulator of the NASA satellite instrument, orbiting on NASA's Terra satellite (ASTER - Advanced Spaceborne Thermal Emission and Reflection Radiometer and MODIS - geographic reprojection tool). It is intended primarily to study geological and other Earth surface properties. Fifty spectral bands cover 435nm - 13,110nm (13.11µm).
4. HyMap Hyperspectral Scanner provides 126 bands across the reflective solar wavelength region of 0.45 - 2.5nm with contiguous spectral coverage (except in the atmospheric water vapor bands) and bandwidths between 15 - 20nm. High spatial and spectral resolution is used for example to differentiate a wide range of minerals at the ground surface through their characteristic absorption spectra.
 |
An example of Hyperspectral imagery. ASTER/MODIS Airborne Simulator from CARTA-2 2005, flight #05-003-31, Track #8. Images were taken at wavelength (from left) of 0.66µm, 1.50µm, 3.74µm, 11.31µm and RGB. Color Infrared Film (CIR): Detects longer wavelengths somewhat beyond the red end of the light spectrum. CIR film was initially employed during World War II to differentiate objects that had been artificially camouflaged. Infrared photography has the same problems that conventional photography has, you need light and clear skies. Even so, CIR is sensitive to very slight differences in vegetation. Because buried archeological features can affect how plants grow above them, such features become visible in color infrared photography. Sources http://www.ghcc.msfc.nasa.gov/archeology/remote_sensing.html Acuña Coto, Victor, Relaciones entre asentamientos precolombinos al norte de Guayabo de Turrialba en la Fase Cabaña. Revista de Ciencias Sociales. Universidad de Costa Rica, 35: 43-52, 1987. Aguilar Piedra, Carlos H. Guayabo de Turrialba; arqueología de un sitio indígena prehispánico. Editorial Costa Rica. San José, 1972. Drolet, Robert, Arqueología e ingeniería hidráulica en Guayabo de Turrialba. In Primer Seminario de Ingeniería de los Recursos Hidrálicos, Colegio de Ingenieros Civiles de Costa Rica, pp. 339- 349, 1984. Lines, Jorge A., Bibliografia antropológica aborigen de Costa Rica San Jose, Costa Rica, 1943. |
