A framework for assessing the salience of landmarks for wayfinding tasks

Background: Landmarks play an important role for the understanding of and reasoning about physical large-scale space. Landmarks also play an important role in every day's spatial tasks, such as wayfinding and navigation. The property of being a landmark has so far been attributed to distinct objects, which are either well known or otherwise unique, such as the Eiffel Tower or a lighthouse on the shore. We propose a framework for the assessment of the landmarkedness of potential landmarks for wayfinding tasks, which is based on the relationship between observer, physical environment, and potential landmark. We argue that landmarkedness is not an inherent property of some object, but rather the result of this tri-lateral configuration. The basic idea is to use this configuration to define the individual components that contribute to the total salience of the object and integrate them in a coherent framework. Main contribution: The framework considers two types of salience: (1) the perceptual salience, which describes the potential of a feature to capture a wayfinder's attention (attentional capture), and (2) the cognitive salience, which explains how strong attention is guided by the wayfinder (attentional orienting). The assessment of the perceptual salience is based on the salience of the incoming stimuli, the perceived concepts, and the spatial layout of a scene, while the cognitive salience considers the subjective importance of the object with respect to the individual's context and knowledge. The most general requirement of a landmark is that it must be salient in some sense. This requires that it contrast with the environment, either in terms of its attributes (i.e., color, texture, etc.), the status of the perceived concept (i.e., church or commercial building), or due to its spatial location with respect to the other objects in the scene (i.e., in the middle of town). Such contrast, however, is only perceivable if the potential landmark is visible from the observer's current point of view. Therefore, for assessing an object's landmarkedness, we consider attributes, objects, and relations to other visible objects only. In addition to the salience perceived from physical contrast, the cognitive abilities of the observer play an important role in selecting appropriate objects for reference. This subjective selection implies that the context, together with our knowledge, thoughts and preconceptions shape what we perceive and finally select as reference for making decisions, which directly influences the assessment of the relative importance or salience of potential landmarks. The assessment of the salience of potential landmarks, hence, needs to consider cognitive aspects, along with the perceptual stimuli. Implications: The accurate assessment of the relative importance of geographic objects is a crucial aspect of many wayfinding-related tools and applications, such as route generation and description algorithms, navigation systems, or location-based services. The integration of appropriate landmarks in such applications decreases the cognitive load put on the wayfinder, and hence increases efficiency and reliability of the application

Classroom Civility

Learning is a sacred, lifelong process that commences in the classroom. We need classrooms that provide safe places to learn. As a student, I urge my classmates to recognize that now is the time to begin debating and discussing that which is hard and controversial. To do this well, both students and professors must work together to form communities built on respect that encourage questioning. Posting by a college student about civility in the classroom from In All Things - an online hub committed to the claim that the life, death, and resurrection of Jesus Christ has implications for the entire world. http://inallthings.org/classroom-civility

Semantic identification of urban green spaces: forest

Urban Green Spaces (UGSs) are recognized as crucial parts of the human-nature ecosystem in densely populated urban centers. Even though they have been intensively studied, an ultimate list of all types of UGSs in Europe still does not exist. This challenges decision making on whether an area should be considered an UGS or belong to another land-use class. Furthermore, the means of precise identification of UGSs are dependent, among others, on their type and semantics. Therefore, in this paper, we investigate forests as UGSs and automatically identify them using their distinct characteristics from Sentinel-2 images as well as descriptive properties derived from them, i.e., vegetation indices and texture metrics.We enrich these properties with forest relevant features such as minimum vegetation height and homogeneity. To assess the reliability of the proposed workflow, we test our approach in two German cities and compare the results with existing governmental land use data sets. With the implemented approach we precisely identify over 90% of the existing forests in the study areas. The main restriction of the approach is the transferability of the thresholds of predictor variables such as homogeneity and dissimilarity

On the assessment of landmark salience for human navigation

In this paper, we propose a conceptual framework for assessing the salience of landmarks for navigation. Landmark salience is derived as a result of the observer's point of view, both physical and cognitive, the surrounding environment, and the objects contained therein. This is in contrast to the currently held view that salience is an inherent property of some spatial feature. Salience, in our approach, is expressed as a three-valued Saliency Vector. The components that determine this vector are Perceptual Salience, which defines the exogenous (or passive) potential of an object or region for acquisition of visual attention, Cognitive Salience, which is an endogenous (or active) mode of orienting attention, triggered by informative cues providing advance information about the target location, and Contextual Salience, which is tightly coupled to modality and task to be performed. This separation between voluntary and involuntary direction of visual attention in dependence of the context allows defining a framework that accounts for the interaction between observer, environment, and landmark. We identify the low-level factors that contribute to each type of salience and suggest a probabilistic approach for their integration. Finally, we discuss the implications, consider restrictions, and explore the scope of the framewor

Towards an ontology of urban green spaces

Growing interest in Urban Green Spaces (UGSs) has led to the discovery of the wide spectrum of services that they either provide or support. Yet, there is persistent confusion about what types of green spaces exist and how they should be classified. Current Land Use (LU) and Land Cover (LC) maps both at European and national levels are either lacking or misclassify various types of UGS, thus underestimating the actual amount of green space that a city offers its citizens. In this paper, we highlight reasons for green space misclassification and suggest an ontology of UGSs. Our ontology takes into account both the physical appearance of UGSs and their semantics. We characterize the physical appearance using four different LC classes while providing semantics using unique characteristics expressed as rules. The ontology proposed emphasizes in particular frequently disregarded small and heterogeneous UGSs and can be used as a basis for their precise identification and mapping

Classifying Urban Green Spaces using a combined Sentinel-2 and Random Forest approach

Environmental and human benefits of Urban Green Spaces (UGSs) have been known for a long time. However, the definition of a reasonable greening strategy still remains challenging due to the lack of sufficient baseline information as well as a lack of consensus what constitutes a UGS. Therefore, accurate identification of the existing green spaces in cities is crucial for developing UGS inventories for urban planning and resource management activities. In this paper we explore the potential of freely available highest resolution multi-spectral remote sensing imagery to identify large homogeneous as well small heterogeneous UGSs. The approach of using a Random Forest classification on Sentinel-2 imagery is shown to be useful to identify various UGSs with a 97 % accuracy. Freely available data and a relatively straightforward implementation of the proposed approach makes it a valuable tool for decision and policy makers

Trajectory data mining: A review of methods and applications

The increasing use of location-aware devices has led to an increasing availability of trajectory data. As a result, researchers devoted their efforts to developing analysis methods including different data mining methods for trajectories. However, the research in this direction has so far produced mostly isolated studies and we still lack an integrated view of problems in applications of trajectory mining that were solved, the methods used to solve them, and applications using the obtained solutions. In this paper, we first discuss generic methods of trajectory mining and the relationships between them. Then, we discuss and classify application problems that were solved using trajectory data and relate them to the generic mining methods that were used and real world applications based on them. We classify trajectory-mining application problems under major problem groups based on how they are related. This classification of problems can guide researchers in identifying new application problems. The relationships between the methods together with the association between the application problems and mining methods can help researchers in identifying gaps between methods and inspire them to develop new methods. This paper can also guide analysts in choosing a suitable method for a specific problem. The main contribution of this paper is to provide an integrated view relating applications of mining trajectory data and the methods used

Identification of microplastics in soils using 2D geometric shape descriptors

Microplastics (MP), until now mostly studied in aquatic ecosystems, are also largely polluting terrestrial ecosystems, especially soil systems. Overall, there is a lack of robust and fast methods to identify, separate and eliminate MPs from soils. This paper is a first attempt to use 2D shape descriptors and Random Forest Machine Learning method in order to discriminate soil and MP particles. The results of this study demonstrate promising potential of the Machine Learning approach and shape descriptors in this relatively new scientific field of determining MPs in soils

Urban sound mapping for wayfinding – a theoretical approach and an empirical study

Conventional navigation systems use visually perceptible landmarks to navigate their users from a starting point to a destination. However, sometimes visual information is not enough for route guidance. Visually-impaired or elderly people may not be able to navigate using the visual sense. Furthermore, there may exist no outstanding (i.e., salient) visual landmarks that could be used to navigate. In such a case auditory information may be a helpful guide. We performed two online studies and a focus-group interview to identify possible sound classes in an urban environment. Based on our results, we gathered sounds in Augsburg and classified them according to their source. The findings support our notion that auditory information can be useful for spatial orientation and guidance in addition to or even replacing visual information

"Landmark Route": A Comparison to the Shortest Route

Most navigation systems for pedestrians output the shortest route. However, there are findings that travellers do not use the shortest route when free to choose. One alternative to minimising spatial distance is the incorporation of landmark information in a shortest route algorithm. Yet, we do not know whether pedestrians prefer such a landmark route over the shortest route. Therefore, we perform a survey and show participants videos of a shortest and a landmark route. We let participants answer questions concerning navigation satisfaction, route communication, and route comparison. Our findings show that the landmark route is more favourable.</p