GIS Shapefile - Analysis of potential stewardship in support of BES research, residential.

Potential stewardship for Residential parcels in Baltimore City summarized by block group. Residential was defined as those parcels with a land use code of residential, residential commercial, residential condominium, or apartments based on the 2003 Maryland Property View A&T database. PRIZM 5, 15, and 62 classes are also present. PRIZM is the Potential Rating Index by Zip code Markets produced by the Claritas Corporation - (http://www.clusterbigip1.claritas.com/claritas/Default.jsp). Total Potential stewardship is that land within a parcels not occupied by buildings, that is land that could potentially support vegetation, regardless of whether or not any vegetation is present. Realized Potential Stewardship is land that is currently occupied by vegetation. Not Realized Potential Stewardship is the land not occupied by buildings or existing vegetation, and is thus the land that is potentially available for "greening" initiatives. Normalization for realized and not realized potential stewardship is carried out by dividing by the total potential stewardship. The potential stewardship was calculated using parcel data, building footprints, and GDT census block groups. Building footprints were erased from the parcel area, resulting in a layer indicating the potential stewardship for each parcel. The potential stewardship layer was then unioned MD DNR's 2001 SUFA vegetation layer. All polygons corresponding to water features were deleted since water features cannot undergo "greening." All polygons that did fall in the potential stewardship area were deleted. This resulted in a layer in which the polygons represented the potential stewardship land along with the potential stewardship land occupied by either grass or trees. This layer was then intersected with the census block group layer resulting in a layer that had the potential stewardship land, potential stewardship vegetation, and block group IDs. All attributes were then summarized at the block group level. A cursory analysis of the parcel data indicated that parcel data was outdated for the following block groups: 245102503031, 245102503032, and 245102503033. Certain block groups with very high Normalized Total Potential Stewardship values may be indicative of the fact that building footprint data was missing, although the extent of this problem is unknown. Note: transportation networks are not part of the parcel data, and thus were appropriately not part of this analysis.

本数据集为巴尔的摩市按普查街区组（census block group）汇总的住宅地块潜在管护用地情况。本数据集中的住宅地块，指基于2003年马里兰州物业视图A&T数据库（Maryland Property View A&T database），土地使用代码为住宅、住宅商业、住宅共管公寓（residential condominium）或公寓的地块。本次数据同时包含PRIZM分类体系中的5、15、62三类；PRIZM是克拉丽塔斯公司（Claritas Corporation）推出的基于邮编市场的潜力评级指数（Potential Rating Index by Zip code Markets），相关链接为http://www.clusterbigip1.claritas.com/claritas/Default.jsp。总潜在管护用地（Total Potential Stewardship）指地块内未被建筑物占用、可潜在用于植被培育的土地，无论当前是否已有植被覆盖；已实现潜在管护用地（Realized Potential Stewardship）指当前已被植被覆盖的土地；未实现潜在管护用地（Not Realized Potential Stewardship）指未被建筑物或现有植被占用的土地，即潜在可用于“绿化”行动的土地。已实现与未实现潜在管护用地的归一化处理，通过将其数值除以总潜在管护用地数值完成。本次潜在管护用地的计算依托地块数据、建筑占地面积（building footprints）及GDT普查街区组数据完成：首先从地块面积中扣除建筑占地面积，生成表征单块地块潜在管护用地的图层；随后将该图层与马里兰州自然资源部（MD DNR）2001年SUFA植被图层进行融合；删除所有对应水体特征的多边形（因水体无法开展绿化行动），同时删除所有落入潜在管护用地范围内的多边形，最终得到同时涵盖潜在管护用地及被草本或木本植被覆盖的潜在管护用地的图层；将该图层与普查街区组图层进行空间相交，得到包含潜在管护用地、潜在管护植被及街区组ID的新图层，并对该图层的所有属性按街区组维度进行汇总统计。对地块数据的初步分析显示，以下普查街区组的地块数据已过时：245102503031、245102503032及245102503033。部分归一化总潜在管护用地数值极高的街区组，可能存在建筑占地面积数据缺失的情况，但该问题的影响范围尚不明确。注：交通路网不属于地块数据范畴，因此未纳入本次分析。