Visualization techniques for an airborne laser scanning‐derived digital terrain model in forested steep terrain: Detecting archaeological remains in the subsurface

Abstract

This paper presents the method used to efficiently identify and map previously unknown subsurface remains in a steep, forested, and mostly unexplored area, within the archaeological site of Porolissum, Romania. The remains are part of the defensive system of the ancient Roman Empire frontiers (Roman limes). The complementary use of high‐resolution airborne laser scanning derived digital terrain model and visualization techniques enabled the detection of 79 new, subsurface archaeological structures, most of which were confirmed by ground inspection to be key elements of the limes. The best performing methods, achieving detection of the maximum visible extent for over 75% of all features were in descending order: principal component analysis, simple local‐relief model, sky‐view factor, and positive openness. Analytical hill‐shading, slope, negative openness, and hill‐shading had a larger proportion of partial detections. The position of these ancient remains supports the hypothesis that this area was extensively deforested, for strategic purposes, during the Roman period. Employing one of the latest remote sensing techniques, we have identified the location of previously unknown, buried ancient structures of the Roman limes in Dacia Province, an essential step for compiling a database necessary for enlisting this Roman limes sector on the World Heritage List.

Why Not a Single Image? Combining Visualizations to Facilitate Fieldwork and On-Screen Mapping

“…All of the visualizations have proved their usefulness in archaeological interpretation in various environmental settings and at diverse scales, (see e.g., References [59][60][61][62][63][64][65][66][67]) and were computed using the relief visualization toolbox (RVT) created by ZRC SAZU [27]. Because we strive to preserve comparability between different geographical areas, the visualizations are presented with a minimum-maximum histogram stretch, usually with a saturation of minimum, maximum, or both.…”

An integrated airborne laser scanning approach to forest management and cultural heritage issues: a case study at Porolissum, Romania

“…The functional role of these structures, established according to the extant historical data, allowed the comprehensive interpretation of the ancient landscape. The synergy of these methods supported the hypothesis that the currently forested area was extensively deforested, for strategic purposes, during the Roman period (Roman et al 2017). LiDAR scanning employs pulses of light that are sent down in swaths.…”

“…Also, the new archaeological remains discovered in the forested area after digitizing terrain models derived from LiDAR data , Roman et al 2017) have been subsequently integrated in a single geodatabase in order to visually asses the overlapping areas.…”

GIS-Based Multi-Criteria Analysis Method for Assessment of Lake Ecosystems Degradation—Case Study in Romania

“…The use of GIS techniques, remote sensing and aerial imagery for various environmental studies is beginning to gain space in Romanian research as well, ranging from urban development, mining industry, water and forest management, biodiversity conservation, and cultural heritage [ 35 ]. GIS techniques were employed for the estimation of the area and depth of a lake in NW Romania after ecological restoration of the wetland.…”

“…The lakes in the mountainous regions are generally less-affected by human activities, but at the same time, they might be fragile from the point of view of slope inclination and permeability, which might privilege the accumulation of pollutants (Figure 11). The use of GIS techniques, remote sensing and aerial imagery for various environmental studies is beginning to gain space in Romanian research as well, ranging from urban development, mining industry, water and forest management, biodiversity conservation, and cultural heritage [35]. GIS techniques were employed for the estimation of the area and depth of a lake in NW Romania after ecological restoration of the wetland.…”