Towards an integrated science of movement

New paper: Miller, H.J., Dodge, S., Miller, J.A. and Bohrer, G. (2019) “Towards an integrated science of movement: Converging research on animal movement ecology and human mobility,” International Journal of Geographical Information Science, 33, 855-876.

Abstract: There is long-standing scientific interest in understanding purposeful movement by animals and humans. Traditionally, collecting data on individual moving entities was difficult and time-consuming, limiting scientific progress. The growth of location-aware and other geospatial technologies for capturing, managing and analyzing moving objects data are shattering these limitations, leading to revolutions in animal movement ecology and human mobility science. Despite parallel transitions towards massive individual-level data collected automatically via sensors, there is little scientific cross-fertilization across the animal and human divide. There are potential synergies from converging these separate domains towards an integrated science of movement. This paper discusses the data-driven revolutions in the animal movement ecology and human mobility science, their contrasting worldviews and, as examples of complementarity, transdisciplinary questions that span both fields. We also identify research challenges that should be met to develop an integrated science of movement trajectories.

Fare-free public transit?

Real estate developer and former longtime Central Ohio Transit Authority board member Bob Weiler has proposed that buses be fare free, spreading the burden with an increase in the county sales tax.

I was a guest on the WOSU public affairs show All Sides with Ann Fisher to discuss fare free public transit, along with Bob Weiler and Patrick Harris (COTA).  You can listen to it here.

Measuring the Geometric and Semantic Similarity of Space–Time Prisms Using Temporal Signatures

New publication: Miller, H.J., Jaegal, Y. and Raubal, M., “Measuring the geometric and semantic similarity of space-time prisms using temporal signatures,” Annals of the American Association of Geographers (online first).

Well-established techniques exist for measuring the similarity of space–time paths. These measures support clustering and aggregation of space–time paths as well as moving objects database queries based on similar movement patterns or semantics. Little attention has been paid, however, to the analogous problem of measuring space–time prism (STP) similarity, despite comparable applications. This article presents and evaluates a method for measuring STP similarity through dimensionality reduction that leverages their inherent temporal ordering. The technique sweeps an STP along the time axis and derives one-dimensional temporal signatures based on a measured STP property that captures its geometry or semantics. These temporal signatures can be visualized directly as curves. We can also apply existing space–time path similarity measures to these signatures. To demonstrate the feasibility of this approach, we perform two sets of experiments measuring geometric and semantic similarity among STPs and assess the information within these curves using visualization, Fréchet distances, and clustering techniques. Results suggest that the temporal signature curves capture meaningful similarities and differences among STPs.

测量时空路径相似性时,有发展完善的科技。这些方法支持时空路径的集群与聚集,以及根据相似的移动模式或语义的移动物件数据库之提问。尽管具有可比较的应用,但却少有对测量时空稜柱(STP)相似性的类似问题之关注。本文呈现并评估通过维度减少来发挥其内在时间次序以测量STP相似性的一种方法。该技术沿着时间轴延伸STP, 并根据捕捉其几何与语义的测得之STP属性,衍生出单维度时间特徵。这些时间特徵能够直接被视觉化为曲线。我们同时可将既有的时空路径相似性测量应用至这些特徵。为了证实此般方法的可行性,我们执行两组测量STPs之间的几何和语义相似性的实验,并运用可视化、弗雷歇距离以及集群技术,取得这些曲线中的信息。研究结果显示,时间特徵曲线捕捉STPs之间有意义的相似性和差异。

Existen técnicas bien probadas para medir la similitud de las trayectorias espacio–tiempo. Estas medidas soportan agrupamiento y agregación de trayectorias espacio–tiempo lo mismo que consultas de bases de datos de objetos en desplazamiento con base en patrones de movimiento o semántica similares. Sin embargo, poca es la atención que se ha deparado al problema análogo de medir la similitud del prisma espacio–tiempo (STP), a pesar de aplicaciones comparables. Este artículo presenta y evalúa un método para medir la similitud del STP mediante la reducción de dimensionalidad que apalanca su inherente ordenamiento temporal. La técnica barre un STP a lo largo del eje del tiempo y deriva firmas temporales unidimensionales basadas en una propiedad STP medida, que captura su geometría o su semántica. Estas firmas temporales pueden visualizarse directamente como curvas. También podemos aplicar a estas firmas las mediciones existentes de similitud de las trayectorias espacio–tiempo. Para demostrar la viabilidad de este enfoque, realizamos dos conjuntos de experimentos midiendo la similitud geométrica y semántica entre STPs y evaluamos la información dentro de estas curvas usando visualización, distancias Fréchet y técnicas de agrupamiento. Los resultados sugieren que las curvas de firma temporal capturan similitudes significativas y diferencias entre los STPs.