Urban Historical Boundaries, 1972

Urban area boundaries for 1972, part of the Baltimore-Washington Spatial Dynamics and Human Impacts dataset. The Baltimore-Washington Spatial Dynamics and Human Impacts dataset is an integrated and flexible temporal urban land characteristics database for the Baltimore-Washington metropolitan area. The compilation of this data is a collaborative effort led by the U.S. Geological Survey and the University of Maryland Baltimore County. The database provides visual and historical perspective of the urban growth experienced in the area between 1792 and 1992. Data on built-up areas exists as separate geographic layers for the dates: 1792, 1801, 1822, 1850, 1878, 1900, 1925, 1938, 1953, 1966, 1972, 1982, and 1992. Temporal urban mapping reconstructs past landscapes by incorporating historic maps, census statistics, and commerce records to generate a progressive geo-referenced picture of the past changes in a region. Contemporary mapping focuses on the use of remotely sensed data, existing digital land use data, digital census information, and a variety of earth science infrastructure data, such as Digital Line Graphs, Digital Elevation Models, and key ancillary demographic information. Different procedures were used for different time periods, more fully described for each file in the Process Step Section 2.5.2. The resulting database of temporal urban land use/land cover and demographic changes provides an ideal source of test data and information for both urban geographers and global change research scientists. While this dataset was developed by the University of Maryland Baltimore County final quality control and metadata generation was performed by the University of Vermont's Spatial Analysis Lab. Two significant problems were noted regarding this dataset. The first anomoly is that the 1801, 1822, and 1878 layers have a much smaller extent, and contain data only for Baltimore City. The second discrepancy is that there are also some very obvious positional errors causing misalignments between layers of different dates (i.e. urban areas become non-urban in a very short time period, an unlikely occurance). This is part of a collection of 221 Baltimore Ecosystem Study metadata records that point to a geodatabase. The geodatabase is available online and is considerably large. Upon request, and under certain arrangements, it can be shipped on media, such as a usb hard drive. The geodatabase is roughly 51.4 Gb in size, consisting of 4,914 files in 160 folders. Although this metadata record and the others like it are not rich with attributes, it is nonetheless made available because the data that it represents could be indeed useful. This is part of a collection of 221 Baltimore Ecosystem Study metadata records that point to a geodatabase. The geodatabase is available online and is considerably large. Upon request, and under certain arrangements, it can be shipped on media, such as a usb hard drive. The geodatabase is roughly 51.4 Gb in size, consisting of 4,914 files in 160 folders. Although this metadata record and the others like it are not rich with attributes, it is nonetheless made available because the data that it represents could be indeed useful.

本数据集为1972年城市区域边界数据，隶属于巴尔的摩-华盛顿空间动态与人类影响（Baltimore-Washington Spatial Dynamics and Human Impacts）数据集。
巴尔的摩-华盛顿空间动态与人类影响数据集是一套面向巴尔的摩-华盛顿大都市区的集成化、灵活易用的时序城市土地特征数据库。本数据集的编制工作由美国地质调查局（U.S. Geological Survey）与马里兰大学巴尔的摩分校联合牵头协作完成。
该数据库可直观展现1792年至1992年间该区域的城市扩张历程与历史变迁。各年份建成区数据以独立地理图层形式存储，涵盖年份包括：1792、1801、1822、1850、1878、1900、1925、1938、1953、1966、1972、1982及1992年。
时序城市制图通过整合历史地图、人口普查统计数据与商业记录，重建区域过往地表景观，逐步生成具备地理参照的区域历史变迁图景。现代城市制图则依托遥感数据、现有数字土地利用数据、数字人口普查信息，以及各类地球科学基础设施数据，如数字线划图（Digital Line Graphs）、数字高程模型（Digital Elevation Models）与关键辅助人口统计数据开展工作。
不同历史时段采用了差异化的制图流程，相关细节已在各文件的2.5.2处理步骤章节中完整说明。
这套整合了时序城市土地利用/土地覆盖与人口变化的数据库，可为城市地理学者与全球变化研究科学家提供优质的测试数据集与参考信息。尽管该数据集由马里兰大学巴尔的摩分校开发完成，但最终的质量控制与元数据生成工作由佛蒙特大学空间分析实验室承担。
本数据集存在两处显著问题：其一，1801、1822与1878年的地理图层覆盖范围极小，仅包含巴尔的摩市范围内的数据；其二，存在较为明显的位置偏移误差，导致不同年份的图层无法精准对齐，例如城市区域在极短时间内变为非城市区域，这一情况不符合现实逻辑。
本数据集属于包含221条巴尔的摩生态系统研究元数据记录的集合之一，指向一个地理数据库。该地理数据库可在线获取，体量较大。经申请并达成特定协议后，可通过USB硬盘等介质邮寄交付。该地理数据库总容量约为51.4GB，包含160个文件夹内的4914个文件。尽管本条元数据及其他同类元数据的属性字段并不丰富，但鉴于其所承载的数据具备较高实用价值，仍予以公开。
本数据集属于包含221条巴尔的摩生态系统研究元数据记录的集合之一，指向一个地理数据库。该地理数据库可在线获取，体量较大。经申请并达成特定协议后，可通过USB硬盘等介质邮寄交付。该地理数据库总容量约为51.4GB，包含160个文件夹内的4914个文件。尽管本条元数据及其他同类元数据的属性字段并不丰富，但鉴于其所承载的数据具备较高实用价值，仍予以公开。