The Federal Highway Administration's Highway Performance Monitoring System (HPMS) and the U.S. Census Bureau's TIGER geospatial database are relied on by countless professionals, but the two databases differ by 6.9 million km (4.3 million miles), a discrepancy greater than the Federal Highway Administration's national total of 6.6 million km (4.1 million miles). While there are several methodological reasons why a GIS network will give different answers from the HPMS, these cannot explain a difference of this magnitude. The difference exists because TIGER was based on roads shown on USGS topographic maps, the majority of which are not considered public highways today. This overestimate of highway extent can affect a range of network operations in GIS. There is, however, reason to consider TIGER's overestimate an underestimate of the actual extent of roads in the country, as well as questioning which roads should be included in a study.

中文翻译：

---

常见 GIS 公路网络空间范围的差异

联邦公路管理局的公路性能监测系统 (HPMS) 和美国人口普查局的 TIGER 地理空间数据库被无数专业人士所依赖，但这两个数据库相差 690 万公里（430 万英里），比联邦公路管理局的国家数据相差更大总计 660 万公里（410 万英里）。虽然 GIS 网络会给出与 HPMS 不同的答案有多种方法论原因，但这些无法解释如此巨大的差异。之所以存在差异，是因为 TIGER 基于美国地质调查局地形图上显示的道路，其中大部分今天不被视为公共高速公路。这种对高速公路范围的高估会影响 GIS 中的一系列网络操作。然而，有理由考虑 TIGER'