Urban Historical Boundaries, 1878

Urban area boundaries for 1878, 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.1878年城市区域边界数据，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》数据集是面向巴尔的摩-华盛顿大都市区的集成化、可扩展时序城市土地特征数据库。本数据集由美国地质调查局（U.S. Geological Survey）与马里兰大学巴尔的摩郡分校（University of Maryland Baltimore County）牵头合作编制。该数据库直观呈现并还原了1792年至1992年间该区域的城市扩张历程。不同年份的建成区数据以独立地理图层形式存储，对应年份分别为1792、1801、1822、1850、1878、1900、1925、1938、1953、1966、1972、1982与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，重建区域过往景观，逐步生成带有地理坐标的区域历史变迁图景。现代城市制图则以遥感数据、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为核心数据源，包括数字线划图（Digital Line Graphs）、数字高程模型（Digital Elevation Models）与关键辅助人口统计信息等。不同历史时期采用了差异化的制图流程，各文件的详细流程说明可参见2.5.2节的处理步骤部分。 最终生成的时序城市土地利用/土地覆盖与人口变化数据库，可为城市地理学家与全球变化研究学者提供优质的测试数据与信息来源。尽管本数据集由马里兰大学巴尔的摩郡分校开发完成，但最终的质量控制与元数据（metadata）生成工作由佛蒙特大学空间分析实验室（University of Vermont's Spatial Analysis Lab）承担。 本数据集存在两处明显问题：其一，1801、1822与1878年的图层覆盖范围显著更小，仅包含巴尔的摩市的相关数据；其二，存在较为明显的位置误差，导致不同年份的图层出现配准偏差（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）。 本数据属于指向地理数据库（geodatabase）的221条巴尔的摩生态系统研究元数据记录之一。该地理数据库体量庞大，可通过线上渠道获取。若满足相关要求并达成约定，也可通过USB硬盘等存储介质寄送。该地理数据库总容量约为51.4 GB，包含160个文件夹下的4914个文件。尽管此类元数据记录的属性信息并不丰富，但鉴于其所承载的数据具有较高的实用价值，仍予以公开。 本数据属于指向地理数据库（geodatabase）的221条巴尔的摩生态系统研究元数据记录之一。该地理数据库体量庞大，可通过线上渠道获取。若满足相关要求并达成约定，也可通过USB硬盘等存储介质寄送。该地理数据库总容量约为51.4 GB，包含160个文件夹下的4914个文件。尽管此类元数据记录的属性信息并不丰富，但鉴于其所承载的数据具有较高的实用价值，仍予以公开。