Indoor Spatial Information

Introduction

Location is gaining increasing attention as the fundamental key to mobile search. Location search covers already 30% of all mobile searches, according to Wikipedia. Enabled by ubiquitous computing, we experience an increasing deployment of location‐based services and smart environments. With the vision of ubiquity, location-based services should clearly not be limited to outdoors, but include indoors as well, in an integrated and seamless manner. In information and communication technologies and software these spatial domains have quite different historic roots, outdoors in GIS and indoors in CAD, and also both worlds have modelled their domain for purposes pre-cursing the advent of ubiquitous computing (Weiser, 1991) and location-based services (Schiller & Voisard, 2004). This observation implies that concepts of (outdoor) location-based services might not be applicable to indoor spaces, and models of indoor spaces might not be applicable to the design of location-based services. Accordingly the development of models and services that target indoor spaces are receiving increasing attention in science (Jensen, Li, & Winter, 2011). There exist at least two reasons why indoor spatial information is attracting attention in geographic information science: a significant demand for indoor spatial information with ubiquitous computing, and lack of knowledge to satisfy this demand.

Demand for indoor spatial information arises from human activities that require some spatiotemporal decision making, i.e., in decision processes where (externally provided) spatiotemporal information is of value. A value can arise from making a different decision than without this additional information—a better one, with regard to some criteria—, or from making a decision more confidently due to this additional information, or where this information enables some time savings in the decision making process. Such considerations can even help quantifying the demand in terms of the value of indoor spatial information (Frank, 2000; Krek, 2002).

Human indoor activities are numerous and belong for example to everyday tasks like orienting or wayfinding in buildings, to specialists’ tasks like facility management or management of the flow of traffic or goods in a building, or to exceptional tasks like evacuating a building in an emergency scenario. These activities create a significant demand on indoor spatial information. Actually, figures are reported that the average North American now spends approximately 90% of their time indoors, with activities like working, living, shopping and entertaining (American Physical Society, 2008, p. 52). We may safely assume that similar figures apply to other societies as well. It is also safe to assume that people spending this time indoors are not always in environments well-known to them, and that indoor environments have a certain rate of change (in emergency situations this rate can even be quite rapid). The latter raises the stakes for dynamic and (near-)real-time indoor information. Another challenge lies in the fact that people are not only staying indoors, but are moving between indoors and outdoors for many of these listed activities. Their decision making processes are not confined to indoor environments.

Satisfying this demand requires significantly different knowledge than the provision of outdoor spatial information. There are several reasons, and some evidence, to assume that the main reason is indoor space being an enclosed space, in contrast to outdoor space. In outdoor environments most activities are limited to a common surface. In indoor environments the third dimension appears in the form of discrete levels, i.e., multiple surfaces. People have more difficulties with wayfinding decisions that involve multiple levels (Hölscher, Meilinger, Vrachliotis, Brösamle, & Knauff, 2006). In addition, indoor space is also private space. This means that access is restricted and regulated. Thus, knowledge about the provision of spatial information that was created for outdoor space must be scrutinized, extended or revised when it comes to indoor space.