The dense canopy of the rainforest normally prevents the detection of archaeological structures. Only when areas have been deforested and vegetation no longer completely hides the structures, it is possible to detect earthworks. LiDAR can penetrate the vegetation with its laser pulses and the resulting data can be used to generate a high-resolution digital terrain model. This makes even subtle landforms visible that are barely discernible on the ground or from the air. 

The data used as the basis for the research and conclusions in this article published in nature have been acquired using a RIEGL airborne laser scanner, the RIEGL LMS-Q780 II-S. Over a flight distance of 4,430 km, approximately 4,497 km² in Southwest Amazonia have been surveyed to define the geographical distribution and quantity of earthworks in the region better. In the course of this work, 432 earthworks were discovered or documented—it is noteworthy that only 36 of these were previously known. On the basis of both existing data and the LiDAR documentation, the researcher team could show that this cultural area alone contains as many earthworks as previously estimated for the whole of Amazonia. Based on this, it can be proposed that the total human population of the area in 100–300 A.D. was significantly higher than previously assumed. If similar results are found elsewhere in Amazonia, the total precolonial population density and its effect on the current Amazonian soil and forest structure, biodiversity and even some modelling of the global climate should be re-evaluated.

The study impressively demonstrates the potential of RIEGL airborne LiDAR for large-scale archaeological prospecting and provides an insight in how the high-quality data is used in detailed analyses and groundbreaking conclusions.

Read the full article here to explore the complete project, workflow, and results.