Benjamin DUCKE
(German Archaeological Institute (DAI), Berlin, Germany)

Keywords: open source GIS, geophysics, gradiometer data, pointclouds

Abstract:
As geophysical sensor technology advances, so do the demands for processing power. Thus, GIS programmers have to seek creative solutions for dealing with extreme amounts of complex and high-density sensor data. With free and open source GIS (FOSS GIS) continuing to gain popularity in archaeology, their level of support for processing such data becomes an issue of great interest.
Recently a number of FOSS GIS projects (such as GRASS GIS, SAGA GIS, QGIS and gvSIG CE) have started to converge on the common aim of processing very large sensor datasets (aka pointclouds) efficiently. Commonly implemented strategies include multi-threaded, parallel processing and rendering, tile-based data management and new efficient file formats, as well as improvements in the data processing tools themselves (such as rapid rasterization and interpolation of point data).
This contribution focuses on the topic of import, error correction and further processing of pointclouds comprising millions of points, coming from multi-sensor gradiometer arrays. It discusses relevant obstacles and limitations in current GIS technology, as well as achievements towards overcoming them. The direct processing of large pointclouds is an important frontline in an effort that will give archaeologists free and powerful tools for working with enormous amounts of sensor data in user-friendly desktop GIS, the integrative platform where such data naturally belongs. This contribution provides an inside view on the latest developments using illustrative examples from the German Archaeological Institute’s recent gradiometer surveys.