micromapST-package: A graphics package to easily and quickly create linked micromaps for the U.S. States

Description

The micromapST package provides a means of creating multiple column graphics representing data from each US state and the District of Columbia. Columns may contain a US map, state ID and several types of charts/glyphs. Each state's graphical element is linked to a small map by means of color.

Arguments

Details

Package:

micromapST

Type:

Package

Version:

1.0.5

Date:

2015-01-21

License:

GPL-2

LazyLoad:

yes

Linked micromap plots link statistical graphs to an organized set of small maps, thus adding geographical context to the graphs. This version creates a linked micromap plot for the 50 U.S. states and the District of Columbia that fits on a single 8.5 inches by 11 inches page in portrait orientation. States are grouped into panels of 5 states each based on the sort variable, with the median-valued state set off in a separate panel in the middle of the page. For each group of states, there is a row of panels comprised of a U.S. map, a list of the state names, and one or more statistical graphics. The order of these panels is specified by the user. The statistical graphics implemented in this version are plots of dots, dots with confidence intervals, horizontal bars, arrows, time series with or without confidence bands, horizontal stacked (segmented) bar charts, scatter plots and boxplots.

The U.S. map of states is a generalized boundary map, based on Mark Monmonier's visibility map. This map is simplified to maximize the color areas shown for each state and to minimize the length of the boundary lines while still allowing identification of each state.

The sort order of the rows (states) is based one of the statistical data columns as specified by the user. Correlation between multiple statistical columns can be judged visually by comparing the pattern of one column's values from top to bottom of the page with that of the sorted column. Spatial clusters of states with similar values of the sorting variable can be identified on the 10 small maps that are linked to the graphics by color.

A state linked micromap plot is generated by 4 steps:

# load the package

library(micromapST)

# read, create or collect your data into a data.frame = stateFrame

stateFrame <- data.frame(a row per state and DC (51), column per variable to be ploted, rownames set to the state names or abbreviations)

# now set up a data frame that defines the labels, # panel and page layout

panelDesc<-data.frame(...)

# specify the data source, panelDesc, sorting variable and # order, and call the stateMicromap function

micromapST(stateFrame,panelDesc, title=c("title1","title2"), details=list(options=values))

The package contains a set of examples of how to produce linked state micromaps. The datasets used in each example are provided to help you learn how to use micromapST.

References

Daniel B. Carr and Linda Williams Pickle, Visualizing Data Patterns with Micromaps, CRC Press, 2010 Linda Williams Pickle, James B. Pearson Jr., Daniel B. Carr (2015), micromapST: Exploring and Communicating Geospatial Patterns in US State Data., Journal of Statistical Software, 63(3), 1-25., http://www.jstatsoft.org/v63/i03/