Скачать или смотреть Evaluating DSMs, RGB and multispectral orthomosaics for UAV-based remote sensing in Mongolia

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From the Aerial Archaeology Research Group 2025 Annual Meeting
https://aargonline.com/wp/events/aarg...

SESSION 5: AERIAL ARCHAEOLOGY FROM EAST TO WEST
Evaluating Digital Surface Models, RGB and multispectral orthomosaics for UAV-based remote sensing in Mongolia by Peter Heimermann

The Bonn Center for Digital Humanities (BCDH) contributes to the DFG-funded project "Urban Impacts on the Mongolian Plateau: Entanglements of Economy, City, and Environment", which investigates urban structures from the Mongol Empire era (1206–1368) and their environmental impact. The subproject "Virtual Landscape and Multispectral Survey" focuses on the applicability of UAV-based remote sensing methods in Mongolia.
Between 2022 and 2024, several UAV campaigns were conducted using a fixed-wing drone equipped with both multispectral and RGB sensors. These surveys produced high-resolution digital surface models (DSMs), as well as RGB and multispectral orthomosaics. A total of 23 archaeological sites covering approximately 10,000 hectares were documented.
To ensure a diverse and versatile dataset, sites from different historical periods (Mongol [1206–1368] and Manchu [18th c.–1911]) and climatic zones (Central Mongolia and the Gobi Desert) were included. Several sites were also surveyed multiple times in different seasons and years, allowing for diachronic and climatic comparisons, as well as multitemporal analysis of drone-based remote sensing data.
The evaluation proceeded in two steps. First, a preliminary selection of vegetation indices (VIs) was made based on their potential to detect archaeological structures. To identify the most effective indices, quantitative contrast analyses were performed on 40 different VIs and four individual bands across selected sites surveyed in both May and September. This enabled a seasonal assessment of index performance and the identification of the most promising candidates for further use.
In a second step, the selected indices were compared to the RGB and DSM datasets. For this, detailed manual mapping of all archaeological structures was carried out using the different data derivatives. Each structure was classified into several categories to facilitate a structured comparison.
Key research questions included: how many structures are visible in each dataset? What types of structures can be identified?
How do disturbance factors like livestock trampling, modern agricultural practices, or dense vegetation impact visibility?
Thanks to the diversity of the dataset, we are able to make broad assessments of the strengths and limitations of various remote sensing methods across different site types, climatic zones, and seasons in Mongolia. The findings highlight which sensor combinations are indispensable for particular environments and archaeological contexts.
Beyond data evaluation, the final outcome of the project includes detailed site plans for all documented locations. These plans will not only support archaeological interpretation but also serve as tools for monitoring preservation conditions, helping to identify dominant threats in a landscape where heritage protection has long been neglected.

Video by ‪@TaleE-library‬