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Shortest Paths

Finding your way through countries.

    
Construct a country graph of Africa:
Wolfram Language code: africa = CountryData["Africa"];
Wolfram Language code: borderQ[cont1_, cont2_] := MemberQ[CountryData[cont1, "BorderingCountries"], CountryData[cont2]];
Wolfram Language code: dist[u_, v_] := GeoDistance[CountryData[u, "CenterCoordinates"], CountryData[v, "CenterCoordinates"]][[1]];
Wolfram Language code: wmat = Table[If[borderQ[u, v] || borderQ[v, u], dist[u, v], ∞], {u, africa}, {v, africa}];
Wolfram Language code: coord = Reverse[CountryData[#, "CenterCoordinates"]& /@ africa, 2];
Wolfram Language code: g = WeightedAdjacencyGraph[africa, wmat, VertexCoordinates -> coord, EdgeStyle -> White, Prolog -> {Hue[.15, .5, .9], CountryData[#, "Polygon"] & /@ africa}, ImagePadding -> 30];
Find a path from Swaziland to Western Sahara:
Wolfram Language code: FindShortestPath[g, CountryData["Swaziland"], CountryData["WesternSahara"]]
Wolfram Language code: HighlightGraph[g, PathGraph[%], GraphHighlightStyle -> "Thick"]