These are non-directed dyad-year data for the minimum distance between states in the Gleditsch-Ward state system from
1946 to 2015. The data are generated from the cshapes package.
gw_mindistA data frame with 868813 observations on the following 4 variables.
gwcode1the Gleditsch-Ward state system code for the first state
gwcode2the Gleditsch-Ward state system code for the second state
yearthe year
mindistthe minimum distance between states on Dec. 31 of the year, in kilometers
The data are generated from the cshapes package. The package authors purport that the data
are generated to be compatible with the Gleditsch-Ward system. I trust them on this; indeed, Gleditsch is one of the
authors of the cshapes package. However, I'm not sure how exhaustive the coverage is. For example,
Tibet is missing in these data and it should not be. I do not use Gleditsch-Ward codes for my own research, so my
quality control here for functions using these data will be minimal. I can only confirm there are no duplicates in the
data.
Data are automatically generated (by default) as directed dyad-years. I elect to make them non-directed for space considerations. Making non-directed dyad-year data into directed dyad-year data isn't too difficult in R. It just looks weird to see the code that does it.
Most of the data I prove elsewhere in this package are to be understood as the data as they were at the *start* of
the year. This is how I process, for example, the capitals data as they get merged in the add_capital_distance()
function. However, the script that generates these data are set at Dec. 31 of the year and not Jan. 1. I do this for concerns
of maximizing data coverage. If you wanted the same effect, just lag the data a year.
Weidmann, Nils B. and Kristian Skrede Gleditsch. 2010. "Mapping and Measuring Country Shapes: The cshapes Package." The R Journal 2(1): 18-24