How can I generate a Geo plot similar to the Wiki page about left- and right-handed traffic.


A direct way would be to make a list of countries that follow L/R traffic handedness and plot. I was wondering if there a way to get this information from the Entity system?

enter image description here

Attribution (link doesn't work): By Benjamin D. Esham (bdesham) - This W3C-unspecified vector image was created with Inkscape ., Public Domain, https://commons.wikimedia.org/w/index.php?curid=2653447

  • 2
    $\begingroup$ Download the .csv file from here and import it $\endgroup$
    – Bob Hanlon
    Commented Apr 3, 2023 at 18:10

1 Answer 1

countries = StringTrim[StringReplace[
        "HTML"], "\r" -> "\n"], "\n"], StringEndsQ[#1, "drives on the left"] & ], 
    {" drives on the left" -> "", RegularExpression["\\([^)]*\\)"] -> ""}]]
interpreter = Interpreter["Country"]
lefties = Sort[Union[Select[interpreter /@ countries,  !FailureQ[#1] & ]]]
all = interpreter /@ CountryData[]
righties = Select[all,  !MemberQ[lefties, #1] & ]
GeoGraphics[{EdgeForm[None], FaceForm[Red], (Polygon[#1, "Polygon"] & ) /@ 
    righties, Entity["AdministrativeDivision", {"Alaska", "UnitedStates"}][
    "Polygon"], FaceForm[Blue], (Polygon[#1, "FullCoordinates"] & ) /@ lefties}, 
  GeoBackground -> "CountryBorders", ImageSize -> Large]

Mathematica graphics

The reason for the special treatment of United States of America Alaska state is because it is missing from the map of the USA in the country data.

  • $\begingroup$ The line of code "righties = Select[all, !MemberQ[lefties, #1] & ]" can be replaced by the line "righties = Complement[all, lefties]". $\endgroup$
    – anon
    Commented Apr 6, 2023 at 14:07

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