Resolution of Ambiguities in Query Interpretation for Geographical Pictorial Query Languages

The main problem of visual query languages for geographical data concerns query ambiguity. A query can have different visual representations, which in turn can have different interpretations. Increasing the number of query objects increases its ambiguity. This derives from the fact that a query can lead to multiple interpretations for both the system and user. The user’s actions may not represent his intentions, leading the system to an incorrect interpretation. So the user cannot express his exact query and different queries must thus be formulated to achieve his goals. This paper proposes an approach that allows the user to represent only desired constraints and avoid undesired constraints in visual query representation

Approximate Query Answering Based on Topological Neighborhood and Semantic Similarity in OpenStreetMap

In this paper we focus on a pictorial query language, referred to as Geographical Pictorial Query Language (GeoPQL), and we revise its formal semantics by considering the polygon-polyline, polyline-polyline, and polygon-polygon topological relationships. This work proposes the Approximate Answering Engine (AAE) within a Distributed System, referred to as GeoPQLJSON (GeoPQLJ). The AAE provides approximate answers to query with empty results by following two directions: the Operator Conceptual Neighborhood (OCN) graph, and the OpenStreetMap (OSM) attribute hierarchy, giving maximum flexibility to the user choices. According to the former, the geo-operators of the queries can be replaced with the ones labeling the adjacent nodes of the OCN graph. By following the latter, the system evaluates the OSM attribute semantic similarity according to the information content approach, and proposes possible attribute replacements to the user. Note that the presence of OSM attributes allows the quick and direct access to large amount of geographical data, without requiring in our case the use of the topological elements. The functionalities of the Distributed GeoPQLJ System are illustrated by several query examples

A Pictorial Query Language for Querying Geographic Databases using Positional and OLAP Operators

The authors propose a declarative Pictorial Query Language (called PQL*) that is able to express queries on an Object-Oriented geographic database drawing the features which form the query. These features refer to the classic ones of a geographic environment (geo-null, geo-points, geo-polyline, and geo-region) and define the alphabet of the above mentioned language. This language, extended with respect to a previous one, considers twelve positional operators and a set of their specifications. Moreover, the possibility to use the mentioned language to query multidimensional databases is discussed. Finally, the characteristic of the mentioned language by a query example is shown.

STORM: A Statistical Object Representation Model

Abstract. In this paper we explore the structure and semantic properties of the entities stored in statistical databases. We call such entities "statistical objects " (SOs) and propose a new "statistical object representation model", based on a graph representation. We identify a number of SO representational problems in current models and propose a methodology for their solution. 1.