ABSTRACT
Chapter 2 introduces various methods for estimating travel impedances (distance and travel time), a common task in spatial analysis and is nearly ubiquitous in data preparation in defining hospital service areas (HSAs). Travel impedance distance measures and travel time[CM1], and the latter varies by transportation modes. This chapter illustrates how to measure an origin-destination (OD) matrix of (1) Euclidean and geodesic distances, (2) automobile drive time, and (3) public transit travel time, in ArcGIS Pro or Google Maps API. When such a matrix is very large, it becomes a major computational challenge. A case study is illustrated to implement the calibration of a nationwide drive time matrix between ZIP code areas in the USA by a differential sampling approach. All related algorithms are automated in customized tools and provided for readers to download and practice.
