GEOMATICS APPLIED TO ARCHEOLOGY 5.2

The Zona Arqueológica Caral has specialists in Geomatics. This includes different techniques for capturing, processing, administrating, analyzing, managing and publishing of geographic information, in this case, of archaeological information.

For maps, base and thematic plans, necessary to start archaeological activities, ZAC has been implementing a Horizontal Control Network linked to the Official Geodetic Reference System, through the use of high precision GNSS receivers.

Maps with contour lines are being prepared using the mandatory lines method, with the use of Total Stations. This requires a meticulous selection of the points to be surveyed by the topographers in detailed drawings, where mandatory lines that must be surveyed during fieldwork are defined. The result is a detailed surface of the structures, useful as an input for other processes related to research as well as knowledge conservation and dissemination.

tion works, and add them to the field reports.

For registration, research and conservation purposes, a three-dimensional scanning of the various archaeological structures intervened by ZAC has been conducted. Data of specific elements and complete sectors is captured with a Total Station with a 3D Scanner, to generate highly precise Digital Elevation Models (DEM). Point Clouds, Triangulated Irregular Networks (TIN) and textured surfaces are also produced. The Point Cloud can be classi -

The engineering software serves to generate products for conservation activities, for example drainage basin maps, which allow simulating the water behavior on the surface of the preserved -or planed to be preserved- sectors. We can extract detailed information from those areas of interest or critical areas, such as longitudinal profiles and cross sections, to implement protection and/or mitigation measures or to build tourism infrastructure. By having detailed records over time, it is possible to quantify earth movements during excava- fied by elevation or by distance, differentiated by colors. Cuts of any length and direction can be generated, as well as contour lines and orthophotos. Qualitative and quantitative information of two-dimensional and three-dimensional accuracy can be extracted from those records, which can be explored by researchers from their location.

Moreover, photogrammetric surveys - aerial and terrestrial - of the archaeological evidence are also being prepared, as a complement to the ongoing three-dimensional 3D scanning. At a macro level, in coordi- nation with the National Geographic Institute-IGN, the photogrammetric survey of the core area of the Sacred City of Caral has been conducted, with two Unmanned Aerial Vehicles-UAV, equipped with cameras and Dual Frequency Differential GNSS for the georeferencing of vertices of high precision photogrammetric control. The survey and processing of the data was conducted by specialized staff of the IGN, with state-ofthe-art equipment, which ensures planimetric accuracy of the order of 10 cm. The main result of this activity is an orthophotomap of the Sacred City of Caral with a spatial resolution of 5 cm.

3D models, obtained at low cost, can be integrated into highly attractive multimedia products for the general public.

From the recorded information, archaeologists can review and illustrate the proposed architectural sequence of the buildings they study. Architectural models include planimetric information, floor levels and wall height to generate three-dimensional reconstructions, which can be included in publications and infographics for dissemination.

Three-dimensional

At a meso-level, sectors and specific architectural elements with terrestrial photogrammetry are being recorded. Next, three-dimensional reconstructions of the records have been generated, which allows extracting quantitative and qualitative information; as well as anaglyph images, three-dimensional reconstructions accessible to the general public, among others. This work also contributes to the register for the conservation of the architectural components, because it allows having textured three-dimensional models, based on which we can obtain precise drawings, multiple cuts, among others.

At a micro level, three-dimensional reconstructions of archaeological materials, such as statuettes, are generated with photogrammetric techniques. The resulting

Other products include videos of general views of archaeological sites, or specific videos for each building, generated by integration of the available three-di- mensional models, created from topographic and photogrammetric surveys, 3D scanning and others.

Geo-referenced archaeological data can also be worked with spatial and spatial statistical analysis tools, to produce three-dimensional maps and scenes facilitating the display of the information resulting from those analyses. For instance, with the Kernel Density, certain archaeological contexts registered during the excavation can be selected, and their minimum and maximum density can be illustrated, either by periods or in general.

Likewise, with tools to measure the geographical distribution of data, such as the Concentration center, Central Entity, Directional Distribution and Standard Distance tools, these trends can be plotted in space and time. Other spatial statistical analysis tools, such as Geographic Distribution and Spatial Autocorrelation, allow for the visualization of spatial groupings or spatial correlations of a specific variable.

Other geographic tools, such as Visual Basin help plot and draw those visible and non-visible spatial areas by one or more observers, located in a specific place, which enhances the architectural analysis.

On the other hand, a Corporate Geographic Information System will be implemented. It includes the start-up of a Geodatabase

SDE and a Geoportal, under the name of GEOZAC, focused on the administration, management and dissemination of information. They can help searching for data on ZAC-managed archaeological sites, or obtaining thematic information about them, based on Dynamic Maps.