Deriving Ephemeral Gullies from VHR Image in Loess Hilly Areas through Directional Edge Detection

Monitoring ephemeral gullies facilitates water planning and soil conservation. Artificial interpretation based on high spatial resolution images is the main method for monitoring ephemeral gullies in large areas; however, this method is time consuming. In this study, a semiautomatic method for extracting ephemeral gullies in loess hilly areas based on directional edge detection is proposed. First, the area where ephemeral gullies developed was extracted because the weak trace of ephemeral gullies in images can hardly be detected by most image detectors, which avoided the noise from other large gullies. Second, a Canny edge detector was employed to extract all edges in the image. Then, those edges along the direction where ephemeral gullies developed were searched and coded as candidate ephemeral gullies. Finally, the ephemeral gullies were identified through filtering of pseudo-gullies by setting the appropriate length threshold. Experiments in three loess hilly areas showed that accuracy ranged from 38.18% to 85.05%, completeness ranged from 82.35% to 92.86%, and quality ranged from 35.29% to 79.82%. The quality of the remote sensing images highly affected the results. The accuracy was significantly improved when the image was used with less grass and shrubs. The length threshold in directional searching also affected the accuracy. A small threshold resulted in additional noise and disconnected gullies, whereas a large threshold disregarded the short gullies. A reasonable threshold can be obtained through the index of quality. The threshold also exhibits a strong relationship with the average length of ephemeral gullies, and this relationship can help obtain the optimum threshold in the hilly area of the Northern Loess Plateau of China

Early Cities or Large Villages? Settlement dynamics in the Trypillia group, Ukraine

This thesis investigates the development of the largest sites - megasites - in Europe during the Chalcolithic (4th millennium BC) and seeks to discuss their urban nature within the wider settlement context of the Trypillia group in modern Ukraine. The study brings together a number of different archaeological datasets and sources, including remote sensing, field survey and legacy data, into a single GIS-based interpretative framework. The assessment of the potential of these sources of information is carried out in order to establish a new field methodology, as well as a nuanced theoretical framework, for the study of the nature of megasites. Quantitative analyses are performed in order to describe trans-scalar patterns in the settlement data, and an interpretative narrative is proposed to explain these patterns and their relevance for the definition of the ‘urban’ nature of megasites. Concepts like ‘seasonality’ and ‘heterarchy’ are used to explain the development and the social organization of megasites, which are conceived as temporary gathering places where an ‘urban-like’ identity starts to develop. The results suggest that Trypillia megasites can be defined as ‘urban forms’ within their coeval settlement and social context, but in the long-term perspective of the last six millennia they are “only” large/overgrown villages. The contribution of this thesis is not only to the specific field of Trypillia archaeology, but it also provides new insights into the wider investigation of the origins of global urbanism

UAVs for the Environmental Sciences

This book gives an overview of the usage of UAVs in environmental sciences covering technical basics, data acquisition with different sensors, data processing schemes and illustrating various examples of application

Dipterocarps protected by Jering local wisdom in Jering Menduyung Nature Recreational Park, Bangka Island, Indonesia

Apart of the oil palm plantation expansion, the Jering Menduyung Nature Recreational Park has relatively diverse plants. The 3,538 ha park is located at the north west of Bangka Island, Indonesia. The minimum species-area curve was 0.82 ha which is just below Dalil conservation forest that is 1.2 ha, but it is much higher than measurements of several secondary forests in the Island that are 0.2 ha. The plot is inhabited by more than 50 plant species. Of 22 tree species, there are 40 individual poles with the average diameter of 15.3 cm, and 64 individual trees with the average diameter of 48.9 cm. The density of Dipterocarpus grandiflorus (Blanco) Blanco or kruing, is 20.7 individual/ha with the diameter ranges of 12.1 – 212.7 cm or with the average diameter of 69.0 cm. The relatively intact park is supported by the local wisdom of Jering tribe, one of indigenous tribes in the island. People has regulated in cutting trees especially in the cape. The conservation agency designates the park as one of the kruing propagules sources in the province. The growing oil palm plantation and the less adoption of local wisdom among the youth is a challenge to forest conservation in the province where tin mining activities have been the economic driver for decades. More socialization from the conservation agency and the involvement of university students in raising environmental awareness is important to be done