Indoor Space Dimensional Model Supporting the Barrier-free Path-finding

In total, about 65 million people have to move by wheelchairs. However, the spatial location service for wheelchair users is one of the scarce aspects in the current geographic information industry. Especially in the poorly-visible indoor spaces, the absence of distributive information for barrier-free facilities will make their movement hard. Therefore, it is of great value to provide indoor location services that support the barrier-free path-finding.The indoor location service is the hotpot in the field of spatial information research at present, and the indoor space model is the basis of the indoor location service which is also the key. In recent years, a variety of indoor space models have been propose,d and they can be divided into semantic models, topological models, geometric models and hybrid models connected in parallel stitching or dimensional ways. It is difficult for users to understand the indoor space merely described by the semantic model. The semantic model is usually used to assist in constructing other types of indoor space models. The grid model has been commonly used, although it can accurately display the position information, it increases the data volume and complexity of the model and reduces the efficiency of the analysis. The topology model is most widely used in indoor path finding, but its lack of location information needs to be complemented with the geometric model. Therefore, the paper proposed a three-layer indoor space dimensional model, it contains geometric information, topological information and semantic information based on several traditional indoor space models. First geometric information, topological information and semantic information were extracted from the source data. Then the general semantic description of the indoor space and the topological relations of indoor space components were constructed. According to different scenes, multiple properties of user's behaviors and components’ states were specified. The three layers of information were merged into a dimensional model, which was the basis for indoor path planning in different scenes. Finally, a hospital building was taken as an example to construct the indoor space model. The geographic information software was used to plan indoor paths for users in ordinary scene and accessible scene respectively. The experiment shows that the indoor space dimensional model is simple to construct, it can adapt to the indoor routing requirements in different scenes and is easy to update.