One size does not fit all: no single optimal algorithm for mobile spatial pointing

The successful emulation of human pointing involves elements of spatial algorithms and databases, Location Based Services, mobile GIS and context awareness. We propose the term Mobile Spatial Pointing (MSP) as a special case of the Mobile Spatial Interaction (MSI) paradigm, where mobile users point at objects in their environment using multi-sensor enabled mobile devices. The goal of this article is to provide experimental evidence that different MSP algorithms are optimal in effectiveness and efficiency depending on context and user intention. A series of experiments with new algorithms were carried out. The experimental results demonstrate that spatial pointing efficacy is influenced by user, physical and computational context-aware aspects. We conclude that no algorithm is optimal for all application situations of digital pointing, whence MSP systems should be designed adaptively using context-aware techniques. Our results exemplify that user intention accurate prediction upon pointing is a determinant factor for developing an MSP system.