Optimised Extraction of Archaeological Features from Full 3-D GPR Data

The use of non-invasive methodologies is becoming essential for archaeological research, and ground penetrating radar is one of the most important techniques to obtain high resolution information. In this paper we present the analysis of a full 3-D GPR dataset integrated with a high-resolution photogrammetric survey acquired in a Roman archaeological site located in Aquileia (Northeast Italy) within the partially excavated area known as “Fondo Pasqualis”. We evaluated the importance of dense and accurate data collection and of processing of the GPR signal for characterization of the archaeological features. We further discuss the parametrization and the applicability of GPR attributes, in particular amplitude-based and coherence attributes, to better identify and characterise the archaeological buried targets. Furthermore, autopicking procedures for isosurfaces mapping were critically evaluated with the objective of detecting complex structures. The final interpretation of all the GPR features, with the support of digital terrain modelling and orthophotos from unmanned aerial vehicles, guided the archaeologists to open and excavate newly selected areas, which revealed interesting structures and contributed to the understanding of the historical events that characterized the Aquileia city.

Robotic embankment

Automating earth-moving tasks has the potential to resolve labour-shortage, allow for unseen designs and foster sustainability through using on-site materials. In this interdisciplinary project involving robotics and landscape architecture, we combine our previous work on autonomous excavation of free-form shapes, dynamic landscape design and terrain modelling tools into a robotic landscape system. It tightly connects survey, design and fabrication to exchange information in real-time during fabrication. We purposely built a LiDAR survey drone for tight integration. The design environment contains terrain modelling tools to balance cut and fill volumes for material-neutral, on-site construction. Its parametric nature allows it to adapt the geometry to changing site conditions during fabrication. Our autonomous walking excavator is used to create these free-form shapes in natural granular material. We propose an excavation planner for free-form embankments that computes the next excavation location and subsequently the location where the excavated soil should be dumped. This robotic excavation system achieves the world’s first autonomous completion of free-form embankments with high accuracy. A $$20\hbox { m}$$ 20 m long S-shaped and a two-faced embankment with a corner with roughly 0.03–0.05 m average error were created.

Systematic review and meta-analysis of risk terrain modelling (RTM) as a spatial forecasting method

Background Several studies have tested the reliability of Risk Terrain Modelling (RTM) by focusing on different geographical contexts and types of crime or events. However, to date, there has been no attempt to systematically review the evidence on whether RTM is effective at predicting areas at high risk of events. This paper reviews RTM’s efficacy as a spatial forecasting method. Methods We conducted a systematic review and meta-analysis of the RTM literature. We aggregated the available data from a sample of studies that measure predictive accuracy and conducted a proportion meta-analysis on studies with appropriate data. Results In total, we found 25 studies meeting the inclusion criteria. The systematic review demonstrated that RTM has been successful in identifying at risk places for acquisitive crimes, violent crimes, child maltreatment, terrorism, drug related crimes and driving while intoxicated (DWI). The proportion meta-analysis indicated that almost half of future cases in the studies analysed were captured in the top ten per cent of risk cells. This typically covers a very small portion of the full study area. Conclusions The study demonstrates that RTM is an effective forecasting method that can be applied to identify places at greatest risk of an event and can be a useful tool in guiding targeted responses to crime problems.

Where should police forces target their residential burglary reduction efforts? Using official victimisation data to predict burglary incidences at the neighbourhood level

Expected crime rates that enable police forces to contrast recorded and anticipated spatial patterns of crime victimisation offer a valuable tool in evaluating the under-reporting of crime and inform/guide crime reduction initiatives. Prior to this study, police forces had no access to expected burglary maps at the neighbourhood level covering all parts of England and Wales. Drawing on analysis of the Crime Survey for England and Wales and employing a population terrain modelling approach, this paper utilises household and area characteristics to predict the mean residential burglary incidences per 1000 population across all neighbourhoods in England and Wales. The analysis identifies distinct differences in recorded and expected neighbourhood burglary incidences at the Output Area level, providing a catalyst for stimulating further reflection by police officers and crime analysts.

Harmonic Correction for Residual Terrain Modelling (RTM) Technique in Physical Geodesy Applications

<p>       In physical geodesy, the harmonic correction (HC), as one of the main problems when using residual terrain modelling (RTM), has become a research focus of high-frequency gravity field modelling. Over past decades, though various methods have been proposed to handle the HC issues for RTM technique, most of them focused on the HC for RTM gravity anomaly rather than other gravity functionals, such as RTM geoid height and gravity gradient. In practice, the HC for RTM geoid height was generally assumed to be negligible, but a quantification is yet studied. In this study, besides the highlighted HC for gravity anomaly in previous studies, the expressions of HC terms for RTM geoid height are provided in the framework of the classical condensation method under infinite Bouguer plate approximation. The errors involved by various assumption of the classical condensation method, e.g., mass inconsistency between infinite masses in the HC and limited masses in the RTM, and planar assumption of the Earth’s surface, are further studied. Based on the derived formulas, the quantification of HC for RTM geoid height when reference surface is expanded to degree and order of 2,159 is given. Our results showed the significance of HC for RTM geoid height, with values up to ~10 cm, in cm-level and mm-level geoid determination. With integration masses extending up to a sufficient distance, such as 1° from calculation point for the determination of RTM geoid height, the errors due to an infinite Bouguer plate approximation are neglectable small. The validation through comparison with terrestrial measurements proved that the HC terms provided in this study can improve the accuracy of RTM derived geoid height and are expected to be useful for applications of RTM technique in regional and global gravity field modelling.</p>

A Influência das Edificações no Cálculo do Efeito Gravitacional das Massas Topográficas – Estudo de Caso na Cidade de Porto Alegre – RS (Brasil)

Um dos objetivos da Geodésia consiste no estudo do geoide e sua determinação é obtida através do conhecimento do campo de gravidade que envolve a distribuição de massas na superfície terrestre. A abordagem clássica para a solução do problema de valor de contorno da Geodésia (PVCG) visando a determinação do geoide assume que os efeitos associados à topografia sejam levados em consideração. A técnica de Modelagem da Topografia Residual (RTM, em inglês Residual Terrain Modelling) tem como objetivo a modelagem o campo de gravidade em função da distribuição de massas associada a topografia onde, nesse tipo de estudo, o conteúdo de alta frequência do espectro relacionado a gravidade é gerado através desse método de redução associado a um modelo digital de elevação (MDE) de alta resolução. Nesse contexto, o objetivo principal desta pesquisa consiste em calcular o valor do potencial gravitacional das massas topográficas oriundas de edificações existentes na cidade de Porto Alegre – RS juntamente com a anomalia de gravidade associada à topografia. Esse estudo foi desenvolvido a partir de uma base vetorial com mais de 200 mil edificações onde o potencial gravitacional foi calculado a partir de um MDE gerado através de dados LiDAR (light detection and ranging). Para auxiliar nos cálculos, foi estimado um modelo de densidades em função das dimensões de cada edificação existentes na base de dados. Assim, foram calculados o valor do potencial gravitacional utilizando os elementos de massa tesseroide, prisma e massa pontual e também o valor da anomalia de gravidade para distâncias de 1 km, 2 km, 5 km, 10 km e 20 km usando a técnica de modelagem RTM. A influência das massas das edificações, neste estudo, representou 10,62% do valor da anomalia de gravidade em comparação com o seu correspondente em relação ao solo.

TERRAIN MODELLING BASED ON ARCHAEOLOGICAL REMAINS IN THE LOESS PLATEAU OF CHINA

The geomorphology of loess plateaus continuously evolves with gully erosion. It is very hard to simulate geomorphic evolution in history, especially considering longer time spans, because of the lack of ancient geographic information. However, historical documents and archaeological sites are providing indispensable information about the past world. Using the remains of Wucheng in the Shanxi Province in China as the study area, we explored the possibility of combining UAV (unmanned aerial vehicle) photogrammetry and GNSS (global navigation satellite system) measurements for modelling current terrain as well as ancient terrain with the help of archaeological surveying. Finally, current and ancient topography were modelled and the soil erosion was assessed. We believe our work can provide a clear workflow for terrain modelling in archaeological sites and may offer new ideas for landform evolution studies.