convertUSCensusStates: Convert US Census state shapefile
In MazamaScience/MazamaSpatialUtils: Spatial Data Download and Utility Functions

convertUSCensusStates

R Documentation

Convert US Census state shapefile

Description

Create a simple features dataframe for US states

The full resolution file will be named "USCensusStates". In addition, "_05", _02" and "_01" versions of the file will be created that that are simplified to 5%, 2% and 1%. Simplified versions will greatly improve the speed of both searching and plotting.

Usage

convertUSCensusStates()

Details

A US state borders shapefile is downloaded and converted to a simple features dataframe with additional columns of data. The resulting file will be created in the spatial data directory which is set with setSpatialDataDir.

The source data is from 2021.

Value

Name of the datasetName being created.

Note

From the source documentation:

Cartographic Boundary Files

The cartographic boundary files are simplified representations of selected geographic areas from the U.S. Census Bureau's Master Address File / Topologically Integrated Geographic Encoding and Referencing (MAF/TIGER) Database (MTDB). These boundary files are specifically designed for small-scale thematic mapping. When possible, generalization is performed with the intent to maintain the hierarchical relationships among geographies and to maintain the alignment of geographies within a file set for a given year. To improve the appearance of shapes, areas are represented with fewer vertices than detailed TIGER/Line equivalents. Some small holes or discontiguous parts of areas are not included in generalized files. Generalized boundary files are clipped to a simplified version of the U.S. outline. As a result, some offshore areas may be excluded from the generalized files.

Limitations

Geographic areas may not align with the same areas from another year. Some geographies are available as nation-based files while others are available only as state-based files.

States and equivalent entities are the primary governmental divisions of the United States. In addition to the fifty states, the Census Bureau treats the District of Columbia, Puerto Rico, and each of the Island Areas (American Samoa, the Commonwealth of the Northern Mariana Islands, Guam, and the U.S. Virgin Islands) as the statistical equivalents of states for the purpose of data presentation.

"Island Areas" are removed in the MazamaSpatialUtils version.

These files were specifically created to support small-scale thematic mapping. To improve the appearance of shapes at small scales, areas are represented with fewer vertices than detailed TIGER/Line Shapefiles. Cartographic boundary files take up less disk space than their ungeneralized counterparts. Cartographic boundary files take less time to render on screen than TIGER/Line Shapefiles. You can join this file with table data downloaded from American FactFinder by using the AFFGEOID field in the cartographic boundary file. If detailed boundaries are required, please use the TIGER/Line Shapefiles instead of the generalized cartographic boundary files.