cities: Distances between 11 US cities
In psychTools: Tools to Accompany the 'psych' Package for Psychological Research

cities

R Documentation

Distances between 11 US cities

Description

Airline distances between 11 US cities may be used as an example for multidimensional scaling or cluster analysis.

Usage

data(cities)

Format

A data frame with 11 observations on the following 11 variables.

ATL: Atlana, Georgia
BOS: Boston, Massachusetts
ORD: Chicago, Illinois
DCA: Washington, District of Columbia
DEN: Denver, Colorado
LAX: Los Angeles, California
MIA: Miami, Florida
JFK: New York, New York
SEA: Seattle, Washington
SFO: San Francisco, California
MSY: New Orleans, Lousianna

Details

An 11 x11 matrix of distances between major US airports. This is a useful demonstration of multiple dimensional scaling.

city.location is a dataframe of longitude and latitude for those cities.

Note that the 2 dimensional MDS solution does not perfectly capture the data from these city distances. Boston, New York and Washington, D.C. are located slightly too far west, and Seattle and LA are slightly too far south.

Source

https://www.timeanddate.com/worldclock/distance.html

Examples


data(cities)
city.location[,1] <- -city.location[,1] #included in the cities data set
plot(city.location, xlab="Dimension 1", ylab="Dimension 2",
   main ="Multidimensional scaling of US cities")
#do the mds   
city.loc <- cmdscale(cities, k=2) #ask for a 2 dimensional solution  round(city.loc,0) 
city.loc <- -city.loc  #flip the axes
 city.loc <- psych::rescale(city.loc,apply(city.location,2,mean),apply(city.location,2,sd))
points(city.loc,type="n") #add the date point to the map
text(city.loc,labels=names(cities))

## Not run:    #we need the maps package to be available
#an overlay map can be added if the package maps is available
if(require(maps)) {
  map("usa",add=TRUE)
}

## End(Not run)

psychTools documentation built on May 29, 2024, 9:47 a.m.