National Historical Geographic Information System

国家历史地理信息系统（NHGIS）是美国最全面的统计数据、地理数据和元数据来源，描述了1790年至今美国人口的空间特征。NHGIS拥有2650亿个数据点，是世界上最大的可公开访问的社会科学数据库，被成千上万的研究人员使用。该项目将对国家公路地理信息系统的基础设施进行四项重大改进。NHGIS将从一个庞大的新的个人层面数据库中为1790-1940年的十年一次的人口普查创建数据表。该项目将为1790至1970年的人口普查编制新的地理信息系统数据，确定合并地方和mcd的位置。人口普查单位的边界在每次人口普查中经常发生变化，因此很难分析人口随时间和空间的变化。NHGIS将对1980年、1990年和2000年的人口普查数据和美国社区调查数据进行插值，得出2010年人口普查区在几个地理水平上的估计，包括人口普查区、地方、县分区和大都市区。最后，该项目将维持和扩大NHGIS的教育和推广工作，提供个人用户支持、面对面研讨会、在线教程和基于网络的社区工具。NHGIS使人口普查民主化，人口普查是美国人口数据的基本来源。拟议的改进将用于学术研究、社会科学培训、新闻、州和地方一级的政策研究以及私营部门的研究。这一基础设施将使从经济学和生态学到环境和卫生政策等学科的数千名研究人员能够在空间组织的精细水平上解决跨越时间的广泛变化。NHGIS为经济和社会进程的空间分析提供了一个独特的实验室，并为开发和测试社会模型提供了必要的经验基础。创建1790年至1940年期间的新的时空数据将为研究美国社会深刻的社会和经济转型提供新的机会，包括工业化、移民、西进移民和城市化。小区域人口普查数据是研究诸如郊区化、中心城市的衰落与重生、居住隔离、移民定居模式、农村人口减少、农业整合以及人口从“铁锈地带”向“阳光地带”转移等关键问题的主要来源。NHGIS的改进将允许研究人员通过扩大本地和区域分析的范围，同时探索跨越时间和空间的变化，将新的和强大的方法应用于熟悉的问题。

The National Historical Geographic Information System (NHGIS) is the nation's most comprehensive source for statistical data, geographic data, and metadata describing spatial characteristics of the American population from 1790 to the present. With 265 billion data points, NHGIS is the largest publicly accessible social science database in the world and is used by thousands of researchers. This project will implement four major improvements to the infrastructure of NHGIS. NHGIS will create data tables for the 1790-1940 decennial censuses from a massive new individual-level database. The project will develop new GIS data identifying locations of incorporated places and MCDs for the 1790-1970 censuses. Census unit boundaries frequently change from one census to the next, making it difficult to analyze population changes over time and space. NHGIS will interpolate census statistics from 1980, 1990, and 2000 and the American Community Survey to produce estimates for 2010 census areas at several geographic levels, including census tracts, places, county subdivisions, and metropolitan areas. Finally, the project will sustain and expand NHGIS education and outreach efforts, offering individual user support and in-person workshops, online tutorials, and web-based community tools. NHGIS democratizes access to the census, the fundamental source of data about the U.S. population. The proposed improvements will be used for academic research and also for social science training, journalism, policy research at the state and local levels, and private sector research. This infrastructure will allow thousands of investigators in disciplines from economics and ecology to environmental and health policy to address changes across the broad sweep of time at fine levels of spatial organization. NHGIS provides a unique laboratory for the spatial analysis of economic and social processes and offers the empirical foundation needed for developing and testing models of society. Creating new spatiotemporal data for the period 1790 through 1940 will open new opportunities to investigate profound social and economic transformations of American society, including industrialization, immigration, westward migration, and urbanization. Small-area census data are the primary source for investigating such critical issues as suburbanization, the decline and rebirth of central cities, residential segregation, immigrant settlement patterns, rural depopulation, agricultural consolidation, and population shifts from the rust belt to the Sunbelt. The improvements to NHGIS will allow researchers to apply new and powerful approaches to familiar problems by broadening the scope of local and regional analyses to explore variations across time and space simultaneously.