GIS Shapefile - Summary of Block Group level analyses for Baltimore City.

Summary of Block Group level analyses for Baltimore City. This dataset contains block group level summary information for riparian vegetation, PROW (public right-of-way) vegetation, private land vegetation, and median age of homes. PRIZM codes are also present. The block group boundaries used in this dataset are from year 2000 GDT census data. The riparian analysis involved summarizing the riparian vegetation (forest and grass only) within a 100ft buffer of all 1:24K streams in Baltimore City for only those block groups that intersect the stream buffers. Vegetation data used in this analysis came from the 2001 MD DNR Forest Service IKONOS-derived Strategic Urban Forest Assessment (SUFA) vegetation layer. The amount of riparian forest, grass, and total vegetation was summarized on a block group level. In addition the percent riparian forest, grass, and total vegetation was summarized at block group level by dividing by the area of riparian land. The PROW analysis involved summarizing all PROW (non-parcel) vegetation (forest and grass) in Baltimore City. The PROW area consists of all roads and rights of way along roads. This area was delineated using Baltimore City parcel data by identifying all "non-parcel" areas. A cursory analysis of the "non-parcel" areas indicated that errors of omission were present due to insufficient parcel data. Vegetation data used in this analysis came from the 2001 MD DNR Forest Service IKONOS derived Strategic Urban Forest Assessment (SUFA) vegetation layer. The amount of urparian forest, grass, and total vegetation was summarized on a block group level. In addition the percent urparian forest, grass, and total vegetation was summarized at block group level by dividing by the area of urparian land. The private land area consists of all parcels not classified as "Exempt" or "Exempt Commerical." A cursory analysis of the parcel data indicated that errors of omission were present due to insufficient parcel data in certain block groups. Vegetation data used in this analysis came from the MD DNR Forest Service IKONOS derived Strategic Urban Forest Assessment (SUFA) vegetation layer. The amount of private land forest, grass, and total vegetation was summarized on a block group level. In addition the percent private land forest, grass, and total vegetation was summarized at block group level by dividing by the area of private land. PRIZM codes are generated from demographic and socioeconomic factors drawn from the U.S. Census data, the Claritas Company's PRIZM system classifies over 260,000 U.S. neighborhood markets into clusters. PRIZM codes can be linked with survey information. More information on PRIZM is available at http://www.clusterbigip1.claritas.com/claritas/Default.jsp?main=3&submenu=seg&subcat=segprizm. Median home age was summarized by block group from U.S. Census data. Credits

巴尔的摩市街区组（Block Group）层面分析综述
本数据集涵盖巴尔的摩市街区组层面的多项汇总统计信息，包含河岸植被、公共通行权用地（PROW, Public Right-of-Way）植被、私有土地植被以及住宅中位房龄数据，同时附带PRIZM编码（PRIZM）信息。

本数据集所使用的街区组边界源自2000年GDT人口普查资料。

本次河岸植被分析仅针对与巴尔的摩市所有1:24000比例尺溪流100英尺缓冲区相交的街区组，统计该范围内的河岸植被（仅包含林地与草地）的相关数据。本次分析所用植被数据源自2001年马里兰州自然资源部（Maryland Department of Natural Resources, MD DNR）森林管理局基于IKONOS影像生成的《城市战略森林评估（SUFA, Strategic Urban Forest Assessment）》植被图层。研究按街区组汇总了河岸林地、草地及总植被的覆盖面积；此外通过除以河岸用地总面积，进一步计算得到各街区组的河岸林地、草地及总植被占比。

公共通行权用地植被分析涵盖巴尔的摩市所有公共通行权用地（非宗地）范围内的林地与草地植被。公共通行权用地范围包含所有道路及沿路通行权区域，该范围通过巴尔的摩市宗地数据识别所有"非宗地"区域完成划定。对"非宗地"区域的初步分析显示，由于部分街区组的宗地数据不足，存在遗漏统计的误差。本次分析所用植被数据同样源自2001年马里兰州自然资源部森林管理局基于IKONOS影像生成的《城市战略森林评估》植被图层。研究按街区组汇总了公共通行权用地上的林地、草地及总植被覆盖面积；此外通过除以公共通行权用地总面积，计算得到各街区组的对应植被占比。

私有土地范围涵盖所有未被归类为"豁免用地"或"商业豁免用地"的宗地。对宗地数据的初步分析显示，由于部分街区组的宗地数据不足，存在遗漏统计的误差。本次私有土地植被分析所用数据源自马里兰州自然资源部森林管理局基于IKONOS影像生成的《城市战略森林评估》植被图层。研究按街区组汇总了私有土地的林地、草地及总植被覆盖面积；此外通过除以私有土地总面积，计算得到各街区组的对应植被占比。

PRIZM编码源自美国人口普查数据中的人口与社会经济因素；克拉丽塔斯公司（Claritas Company）的PRIZM系统可将全美超过26万个邻里市场划分为不同聚类，且PRIZM编码可与调研信息进行关联匹配。关于PRIZM的更多信息可访问：http://www.clusterbigip1.claritas.com/claritas/Default.jsp?main=3&submenu=seg&subcat=segprizm。

住宅中位房龄数据按街区组从美国人口普查资料中汇总得到。
致谢