2010-2014 ACS Transportation to Work Variables - Boundaries

This layer contains 2010-2014 American Community Survey (ACS) 5-year data, and contains estimates and margins of error. The layer shows workers' place of residence by mode of commute. This is shown by tract, county, and state boundaries. There are also additional calculated attributes related to this topic, which can be mapped or used within analysis. This layer is symbolized by the percentage of workers who drove alone. To see the full list of attributes available in this service, go to the "Data" tab, and choose "Fields" at the top right. Vintage: 2010-2014 ACS Table(s): B08301 (Not all lines of this ACS table are available in this feature layer.) Data downloaded from: Census Bureau's API for American Community Survey Date of API call: November 28, 2020 National Figures: data.census.gov The United States Census Bureau's American Community Survey (ACS): About the Survey Geography & ACS Technical Documentation News & Updates This ready-to-use layer can be used within ArcGIS Pro, ArcGIS Online, its configurable apps, dashboards, Story Maps, custom apps, and mobile apps. Data can also be exported for offline workflows. For more information about ACS layers, visit the FAQ. Please cite the Census and ACS when using this data. Data Note from the Census: Data are based on a sample and are subject to sampling variability. The degree of uncertainty for an estimate arising from sampling variability is represented through the use of a margin of error. The value shown here is the 90 percent margin of error. The margin of error can be interpreted as providing a 90 percent probability that the interval defined by the estimate minus the margin of error and the estimate plus the margin of error (the lower and upper confidence bounds) contains the true value. In addition to sampling variability, the ACS estimates are subject to nonsampling error (for a discussion of nonsampling variability, see Accuracy of the Data). The effect of nonsampling error is not represented in these tables. Data Processing Notes: This layer has associated layers containing the most recent ACS data available by the U.S. Census Bureau. Click here to learn more about ACS data releases and click here for the associated boundaries layer. The reason this data is 5+ years different from the most recent vintage is due to the overlapping of survey years. It is recommended by the U.S. Census Bureau to compare non-overlapping datasets. Boundaries come from the US Census TIGER geodatabases. Boundary vintage (2014) appropriately matches the data vintage as specified by the Census. These are Census boundaries with water and/or coastlines clipped for cartographic purposes. For census tracts, the water cutouts are derived from a subset of the 2010 AWATER (Area Water) boundaries offered by TIGER. For state and county boundaries, the water and coastlines are derived from the coastlines of the 500k TIGER Cartographic Boundary Shapefiles. The original AWATER and ALAND fields are still available as attributes within the data table (units are square meters). The States layer contains 52 records - all US states, Washington D.C., and Puerto Rico Census tracts with no population that occur in areas of water, such as oceans, are removed from this data service (Census Tracts beginning with 99). Percentages and derived counts, and associated margins of error, are calculated values (that can be identified by the "_calc_" stub in the field name), and abide by the specifications defined by the American Community Survey. Field alias names were created based on the Table Shells file available from the American Community Survey Summary File Documentation page. Negative values (e.g., -4444...) have been set to null, with the exception of -5555... which has been set to zero. These negative values exist in the raw API data to indicate the following situations: The margin of error column indicates that either no sample observations or too few sample observations were available to compute a standard error and thus the margin of error. A statistical test is not appropriate. Either no sample observations or too few sample observations were available to compute an estimate, or a ratio of medians cannot be calculated because one or both of the median estimates falls in the lowest interval or upper interval of an open-ended distribution. The median falls in the lowest interval of an open-ended distribution, or in the upper interval of an open-ended distribution. A statistical test is not appropriate. The estimate is controlled. A statistical test for sampling variability is not appropriate. The data for this geographic area cannot be displayed because the number of sample cases is too small.本图层包含2010-2014年美国社区调查（American Community Survey, ACS）5年期数据，涵盖估算值与误差边际。本图层以人口普查区（tract）、县（county）及州（state）界为范围，展示了通勤方式对应的劳动者居住地分布情况。此外还包含与该主题相关的额外计算属性，可用于制图或分析工作。本图层以独自驾车通勤的劳动者占比作为符号化依据。如需查看本服务中可用属性的完整列表，请切换至「数据」选项卡，并点击右上角的「字段」选项。 数据年份：2010-2014年；ACS表编号：B08301（本要素图层未涵盖该ACS表的全部条目。） 数据来源：美国人口普查局美国社区调查API API调用日期：2020年11月28日 全国统计数据：data.census.gov 美国人口普查局美国社区调查（ACS）：调查简介、地理信息规范、ACS技术文档及最新动态 本图层为即用型数据，可在ArcGIS Pro、ArcGIS Online及其可配置应用、仪表盘、故事地图（Story Maps）、自定义应用及移动应用中使用。数据亦可导出用于离线作业流程。 如需了解ACS图层的更多信息，请访问常见问题解答（FAQ）页面。使用本数据时，请注明引用美国人口普查局与ACS。 美国人口普查局数据说明：本数据基于抽样调查，存在抽样变异性。由抽样变异性导致的估算值不确定程度通过误差边际体现。此处展示的为90%置信水平的误差边际。误差边际可理解为：估算值减去误差边际与估算值加上误差边际所构成的区间（即置信上下限）有90%的概率包含真实数值。除抽样变异性外，ACS估算值还存在非抽样误差（关于非抽样变异性的讨论，请参阅《数据精度》文档）。本表格未体现非抽样误差的影响。 数据处理说明：本图层附带关联图层，包含美国人口普查局发布的最新ACS数据。点击此处可了解ACS数据发布的更多详情，点击此处可访问关联的边界图层。本数据与最新数据年份相差5年以上，系因调查年份存在重叠。美国人口普查局建议使用非重叠数据集进行对比分析。 本图层的边界数据源自美国人口普查局TIGER地理数据库。边界数据年份（2014年）与普查局指定的数据年份完全匹配。为满足制图需求，普查边界已裁剪掉水域及海岸线部分。对于人口普查区，水域裁剪范围源自TIGER提供的2010年水域面积（AWATER）边界子集；对于州和县界，水域及海岸线数据源自50万比例尺TIGER制图边界Shapefile的海岸线数据。原始水域面积（AWATER）与陆地区域面积（ALAND）字段仍作为属性保留在数据表中（单位：平方米）。 州图层共包含52条记录，涵盖美国全部州、华盛顿哥伦比亚特区及波多黎各。 位于海洋等水域区域的无人口普查区已从本数据服务中移除（即编号以99开头的普查区）。 占比、衍生计数及关联误差边际均为计算所得值（可通过字段名中的"_calc_"前缀识别），且符合ACS的规范要求。字段别名基于美国社区调查摘要文件文档页面提供的表框架文件生成。 原始API数据中的负值（如-4444...）已被设置为空值，其中-5555...除外，已被设置为0。原始API数据中的负值用于表示以下情形： 1. 误差边际列表示：无有效样本观测值或样本观测值过少，无法计算标准误及误差边际，此时不适合进行统计检验。 2. 无有效样本观测值或样本观测值过少，无法计算估算值；或因其中一个或两个中位数估算值落在开放式分布的最低区间或最高区间，无法计算中位数比值。 3. 中位数落在开放式分布的最低区间或最高区间。 4. 不适合进行统计检验。 5. 估算值为受控值，此时不适合针对抽样变异性进行统计检验。 6. 样本量过小，无法展示该地理区域的数据。