Vertical Indexing for Moving Objects in Multifloor Environments

Abstract

e indexing and tracking of objects moving in indoor spaces has increasingly become an important area of research, which presents a fundamentally different challenge. ere are two main reasons for why indoor should be treated as cellular space. Firstly, an indoor space has entities, such as rooms and walls, that constrain the movement of the moving objects. Secondly, the relevant notion of locations of an object is cell based rather than an exact Euclidean coordinate. As a solution, in our earlier works, we proposed a cell-based indexing structure, called the C-tree, for indexing objects moving in indoor space. In this paper, we extend the C-tree to solve another interesting problem. It can be observed that many indoor spaces (such as shopping centers) contain wings/sections. For such a space, there are queries for which the wing/section location of an object, rather than the cellular location, is the relevant answer (e.g., "the object is in the east wing"). In this paper, we propose a new index structure, called the GMI-tree ("GMI" stands for "Graph-based Multidimensional Index"). e GMI-tree is based on two notions of distance, or equivalently, two notions of adjacency: one represents horizontal adjacency and the other represents vertical adjacency.

An Efficient Shortest Path Routing Algorithm for Directed Indoor Environments

“…Moreover, most of the current indoor space data structures and querying do not consider the density of objects moving in indoor space, which actually has an important impact on movement indoors [26][27][28]. Moreover, any spatial queries such as routing or KNN queries in indoor spaces can easily be affected by the cell density.…”

“…Therefore, this work concentrates on building a routing approach for these kinds of indoor spaces. Moreover, the density of the moving objects in indoor space has not been considered in most of the research on routing or querying in indoor spaces [1,8,27]. Thus, this work also considers the density of the moving objects inside the cells/rooms in the directed indoor space, which has an important impact on the movement of the objects.…”

Spatial data managements in indoor environments

“…However, the index structure of the directed indoor space is complex. Moreover, because the indoor space is directed, issues such as density of objects may arise (Alamri et al , 2013d, 2018). For example, in a museum, many moving objects may be gathered in a section where a demonstration is being presented, which makes that cell a dense cell.…”

“…The following are the most common space structures of spatial data: Euclidean space, spatial road network and cellular space. Euclidean space, the distance between object A and B , is the straight line between them (Xuan et al , 2008; Alamri et al , 2018). Figure 1 shows an example of the Euclidean space measurement query where A wants to retrieve the Euclidean distance between its location and object B.…”