Boscoe Francis P, Henry Kevin A, Zdeb Michael S
New York State Cancer Registry.
Prof Geogr. 2012 Apr 1;64(2). doi: 10.1080/00330124.2011.583586.
Many geographic studies use distance as a simple measure of accessibility, risk, or disparity. Straight-line (Euclidean) distance is most often used because of the ease of its calculation. Actual travel distance over a road network is a superior alternative, although historically an expensive and labor-intensive undertaking. This is no longer true, as travel distance and travel time can be calculated directly from commercial Web sites, without the need to own or purchase specialized geographic information system software or street files. Taking advantage of this feature, we compare straight-line and travel distance and travel time to community hospitals from a representative sample of more than 66,000 locations in the fifty states of the United States, the District of Columbia, and Puerto Rico. The measures are very highly correlated ( > 0.9), but important local exceptions can be found near shorelines and other physical barriers. We conclude that for nonemergency travel to hospitals, the added precision offered by the substitution of travel distance, travel time, or both for straight-line distance is largely inconsequential.
许多地理研究将距离作为可达性、风险或差异的一种简单度量。直线(欧几里得)距离因其计算简便而最为常用。实际的路网旅行距离是更好的选择,尽管从历史上看这是一项昂贵且劳动密集的工作。现在情况已非如此,因为旅行距离和旅行时间可以直接从商业网站计算得出,无需拥有或购买专门的地理信息系统软件或街道文件。利用这一特性,我们从美国五十个州、哥伦比亚特区和波多黎各的66000多个地点的代表性样本中,比较了到社区医院的直线距离、旅行距离和旅行时间。这些度量之间的相关性非常高(>0.9),但在海岸线和其他自然屏障附近会发现重要的局部差异。我们得出结论,对于前往医院的非紧急出行,用旅行距离、旅行时间或两者替代直线距离所带来的额外精度在很大程度上无关紧要。