An Ontology for Grounding Vague Geographic Terms

Many geographic terms, such as “river” and “lake”, are vague, with no clear boundaries of application. In particular, the spatial extent of such features is often vaguely carved out of a continuously varying observable domain. We present a means of defining vague terms using standpoint semantics, a refinement of the philosophical idea of supervaluation semantics. Such definitions can be grounded in actual data by geometric analysis and segmentation of the data set. The issues raised by this process with regard to the nature of boundaries and domains of logical quantification are discussed. We describe a prototype implementation of a system capable of segmenting attributed polygon data into geographically significant regions and evaluating queries involving vague geographic feature terms

Representations of an Urban Neighborhood: Residents’ Cognitive Boundaries of Koreatown, Los Angeles

The neighborhood has long been studied in such fields as geography, sociology, political science, and urban planning as a meaningful unit of analysis, with deep connections for residents and an ever-shifting form. This study expands on foundational research about geographic regions (particularly informal or vague cognitive regions), sense of place, and environmental and travel perception, and takes as its focal area the neighborhood of Koreatown in Los Angeles. By collecting information about residents’ individual attributes, their concepts of this neighborhood region, and their travel activity within the city, I elucidate how ideas about the neighborhood fit into theories about sense of place. My work additionally demonstrates the value of surveying residents about vague concepts of local regions, and ways in which to measure and express these ideas.I conducted in-person surveys to explore the connection between residents’ cognitive boundaries of Koreatown, through drawn boundaries and explanations, and their behavior within the city of LA, represented by activity space measures. In doing so, I find ways in which respondents’ cognitive boundaries of the Koreatown neighborhood align with and differ from otherwise established definitions of Koreatown, presenting two methods of evaluating individual boundaries of a region. One of these ways of comparing polygons, the radial intersect method, is originally extended to the summary of multiple polygons. Collected temporary travel behavior of respondents provides a way of depicting respondents’ activity spaces in the LA region for comparison with their cognitive regions. Survey data is supplemented with socio-demographic data from the Census and field observations to contextualize these findings by looking at residential clustering and ethnic composition in the neighborhood and the greater Los Angeles region. My research makes an important contribution to our understanding of the urban neighborhood through an extensive analysis of a unique ethnic enclave from the perspective of local residents in one of the nation’s largest metropolises

Semantic categories underlying the meaning of ‘place’

This paper analyses the semantics of natural language expressions that are associated with the intuitive notion of ‘place’. We note that the nature of such terms is highly contested, and suggest that this arises from two main considerations: 1) there are a number of logically distinct categories of place expression, which are not always clearly distinguished in discourse about ‘place’; 2) the many non-substantive place count nouns (such as ‘place’, ‘region’, ‘area’, etc.) employed in natural language are highly ambiguous. With respect to consideration 1), we propose that place-related expressions should be classified into the following distinct logical types: a) ‘place-like’ count nouns (further subdivided into abstract, spatial and substantive varieties), b) proper names of ‘place-like’ objects, c) locative property phrases, and d) definite descriptions of ‘place-like’ objects. We outline possible formal representations for each of these. To address consideration 2), we examine meanings, connotations and ambiguities of the English vocabulary of abstract and generic place count nouns, and identify underlying elements of meaning, which explain both similarities and differences in the sense and usage of the various terms

An Introduction to Ontology

Analytical philosophy of the last one hundred years has been heavily influenced by a doctrine to the effect that one can arrive at a correct ontology by paying attention to certain superficial (syntactic) features of first-order predicate logic as conceived by Frege and Russell. More specifically, it is a doctrine to the effect that the key to the ontological structure of reality is captured syntactically in the ‘Fa’ (or, in more sophisticated versions, in the ‘Rab’) of first-order logic, where ‘F’ stands for what is general in reality and ‘a’ for what is individual. Hence “f(a)ntology”. Because predicate logic has exactly two syntactically different kinds of referring expressions—‘F’, ‘G’, ‘R’, etc., and ‘a’, ‘b’, ‘c’, etc.—so reality must consist of exactly two correspondingly different kinds of entity: the general (properties, concepts) and the particular (things, objects), the relation between these two kinds of entity being revealed in the predicate-argument structure of atomic formulas in first-order logic

Investigating behavioural and computational approaches for defining imprecise regions

People often communicate with reference to informally agreedplaces, such as “the city centre”. However, views of the spatial extent of such areas may vary, resulting in imprecise regions. We compare perceptions of Sheffield’s City Centre from a street survey to extents derived from various web-based sources. Such automated approaches have advantages of speed, cost and repeatability. We show that footprints from web sources are often in concordance with models derived from more labour-intensive methods. Notable exceptions however were found with sources advertising or selling residential property. Agreement between sources was measured by aggregating them to identify locations of consensus

Semantics matters: cognitively plausible delineation of city centres from point of interest data

We sketch a workflow for cognitively plausible recognition of vague geographical concepts, such as a city centre. Our approach imitates a pedestrian strolling through the streets, and comparing his/her internal cognitive model of a city centre with the stimulus from the external world to decide whether he/she is in the city centre or outside. The cognitive model of a British city centre is elicited through an online questionnaire survey and used to delineate referents of city centre from point of interest data. We first compute a measure of ‘city centre-ness’ at each location within a city, and then merge the area of high city centre-ness to a contiguous region. The process is illustrated on the example of the City of Bristol, and the computed city centre area for Bristol is evaluated by comparison to reference areas derived from alternative sources. The evaluation suggests that our approach performs well and produces a representation of a city centre that is near to people’s conceptualisation. The benefits of our work are better (and user-driven) descriptions of complex geographical concepts. We see such models as a prerequisite for generalisation over large changes in detail, and for very specific purposes