Communities of Concern - SCAG Region

Using data from the 2009-13 ACS 5 Year Estimates at the Census Designated Place level (CDP), calculate total percentage of minority population and total percentage of households in poverty for each CDPAlso using census tract data from the 2009-13 ACS 5 Year Estimates, tabulate percentage of minority population and total percentage of households in poverty for each City of Los Angeles Community Planning Area (CPAs)Intersect CPAs with Census Tracts and tabulate new totals for partial CPA/Census Tracts based on spatial interpolationSum total Poverty, households, minority, and population values for each CPAMerge CDPs and City of Los Angeles Community Planning Areas to create a single “Place” file for the entire SCAG region. Remove the City of Los Angeles CDP from layer. Tabulate % of households in poverty and % of minority population for each “Place”Using ranked sorting, select the places that are in the upper third in the SCAG region for both % of households in poverty (x > 0.169156) and% minority (x > 0.768549)Identify those places and export to new shapefile – “Communities_of_Concern”Union “Communities_of_Concern” shapefile with Tier2 TAZ file and tabulate % of each tract that falls in “Communities_of_Concern”Calculate total square meters in Tier2 TAZ shapefileUnion shapefile with “Communities_of_Concern”Tabulate new square meters in Tier 2 TAZ shapefileExport attribute table to DBFLoad DBF in excel and use pivot tables to tabulate total acreage by TAZ only for tracts that intersect with “Communities_of_Concern”. Create new DBF with results and load into ArcMapJoin new DBF with Tier2 TAZ shapefile and calculate % of TAZ that falls in “Communities_of_Concern” only for the records that join. All other TAZs remain 0%, if they do not intersect.

本研究采用2009-2013年美国社区调查（American Community Survey, ACS）5年估算数据集的普查指定地点（Census Designated Place, CDP）层级数据，计算每个普查指定地点的少数族裔人口占比与贫困家庭占比。同时采用同期普查街区（Census Tract）层级的ACS 5年估算数据，统计洛杉矶市各社区规划区（City of Los Angeles Community Planning Area, CPAs）的少数族裔人口占比与贫困家庭占比。将社区规划区与普查街区进行空间相交分析，并基于空间插值法统计部分重叠的社区规划区-普查街区组合的新汇总值。汇总每个社区规划区的贫困家庭数、总家庭数、少数族裔人口数与总人口数。将普查指定地点与洛杉矶市社区规划区进行要素合并，为整个南加州政府协会（Southern California Association of Governments, SCAG）区域生成单一的"Place"图层；从该图层中移除洛杉矶市对应的普查指定地点，并统计每个"Place"的贫困家庭占比与少数族裔人口占比。通过排序筛选，选取SCAG区域内贫困家庭占比（x > 0.169156）与少数族裔人口占比（x > 0.768549）均处于前三分之一区间的地点。提取符合条件的地点并导出为新的shapefile文件，命名为"Communities_of_Concern"。将"Communities_of_Concern" shapefile与二级交通分析区（Tier2 Traffic Analysis Zone, Tier2 TAZ）文件进行空间融合分析，统计每个普查街区落入"Communities_of_Concern"的面积占比。计算二级交通分析区shapefile的总面积（单位：平方米）。将二级交通分析区shapefile与"Communities_of_Concern"进行空间融合。统计融合后二级交通分析区shapefile的新增面积（单位：平方米）。将要素属性表导出为DBF格式文件（dBase File, DBF）。将DBF文件导入Excel，通过数据透视表仅统计与"Communities_of_Concern"存在空间相交的交通分析区的总占地面积（单位：英亩）；将统计结果生成新的DBF文件并导入ArcMap。将新生成的DBF文件与二级交通分析区shapefile进行属性连接，仅对成功连接的记录计算其落入"Communities_of_Concern"的面积占比；未发生空间相交的交通分析区占比保持为0%。