Presenting spatial information: Granularity, relevance, and integration

In recent years the availability of automatically generated spatial information of various kinds has developed dramatically. Route descriptions of diverse kinds can be obtained from many different sources and across different modalities, and maps and geographic information can be accessed in multifarious ways. Although this is situation improves the information availability and accessibility— think, for example, of car navigation, local search, or holiday trip planning, and how all of them have fundamentally changed over the past few years—Internet users may not always be comfortable with the ways in which the information has to be requested or is presented. Recent research has shown that automatically generated spatial information exhibits fundamentally different features from information provided naturally by humans, when asked about space and time in route directions, for example. The human-computerinterface remains the last barrier to easy-to-consume spatial information, or in other words to intelligent machines [3]. Therefore, our contention is that substantial further work is required in order to render spatial information services more supportive and cognitively suitable. This theme section centers on issues pertaining to granularity, relevance, and integration of spatial information in this communication triangle between user, machine, and environment. Spatial information can be requested by, or presented to information seekers on various levels of granularity, ranging from coarse information concerning features at geographic scale, to detailed information concerning concrete spatial actions in environments of vista scale [1]. Not all of this information is relevant for all purposes. Decisions concerning granularity are directly intertwined with issues of relevance across interaction scenarios. Such scenarios frequently require an ability to move between different spatial and temporal granularities. Consider, for example, a train journey: the traveler needs to know the departure time on the minute, where to buy a ticket, the departure platform at the train station, and the section of the platform where the carriage with the reserved seat will stop. Once on board, the traveler might be interested in information about the progress of the trip, but this information is irrelevant during the planning phase of the trip. Next, the traveler needs to know the time of arrival in the destination city, but generally not the arrival platform [2]. In spite of this complex relationship between granularity and relevance humans typically manage to present information in an integrated and coherent way, switching flexibly