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It seems to be an easy task as all the related functions GeoNearest and EntityList["City"] are close at hands.

However, for example, if we use

GeoNearest["City", Entity["Ocean", "PacificOcean"], 30]

to retrieve some cities, as the query size could be huge, we will always get such error: enter image description here

So, what would be the sensible/feasible approach to get a global list of coastal cities using the Entity framework?

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  • $\begingroup$ I think that the first thing I would try if I was on a machine with Mathematica installed would be to get a list of cities with elevations less than some threshold, say 50m, and see what pops out. I suspect selecting cities on a simple criterion like the value of a property will be a lot less computationally burdensome than the GeoNearest[ ... theOcean] approach. $\endgroup$
    – High Performance Mark
    Jan 6, 2022 at 17:08
  • $\begingroup$ Well, I just tried my previous suggestion in MMA online, got a list of ~28,000 cities! $\endgroup$
    – High Performance Mark
    Jan 6, 2022 at 17:16
  • $\begingroup$ @HighPerformanceMark it would also be possible to filter those after the fact, since 28K is much easier to work with $\endgroup$
    – b3m2a1
    Jan 6, 2022 at 17:24
  • $\begingroup$ Yes, that's rather the way I was suggesting OP goes. $\endgroup$
    – High Performance Mark
    Jan 6, 2022 at 18:53

1 Answer 1

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As a workaround you can use the ocean polygon instead, e.g.:

GeoNearest[
    "City",
    Entity["Ocean","PacificOcean"]["Polygon"],
    30
]

{Entity["City", {"Avera", "Tubuai", "FrenchPolynesia"}], Entity["City", {"Niusuatia", "Tuamasaga", "Samoa"}], Entity["City", {"Uturoa", "IlesSousLeVent", "FrenchPolynesia"}], Entity["City", {"Fakahima", "TuamotuGambier", "FrenchPolynesia"}], Entity["City", {"Salesatele", "Atua", "Samoa"}], Entity["City", {"Sapulu", "FaAsaleleaga", "Samoa"}], Entity["City", {"Samamea", "VaAOFonoti", "Samoa"}], Entity["City", {"Tafagamanu", "AAna", "Samoa"}], Entity["City", {"Vailoa", "Tuamasaga", "Samoa"}], Entity["City", {"Anaa", "TuamotuGambier", "FrenchPolynesia"}], Entity["City", {"Ofu", "Manua", "AmericanSamoa"}], Entity["City", {"Papeete", "IlesDuVent", "FrenchPolynesia"}], Entity["City", {"SalelavaluTai", "FaAsaleleaga", "Samoa"}], Entity["City", {"Paepaeala", "AigaILeTai", "Samoa"}], Entity["City", {"Afega", "Tuamasaga", "Samoa"}], Entity["City", {"Faleu", "AigaILeTai", "Samoa"}], Entity["City", {"Taahuaia", "Tubuai", "FrenchPolynesia"}], Entity["City", {"Asaga", "FaAsaleleaga", "Samoa"}], Entity["City", {"Tufutafoe", "Vaisigano", "Samoa"}], Entity["City", {"ApolimaIsland", "AigaILeTai", "Samoa"}], Entity["City", {"SiumuUta", "Tuamasaga", "Samoa"}], Entity["City", {"Faleseela", "AAna", "Samoa"}], Entity["City", {"Maupiti", "IlesSousLeVent", "FrenchPolynesia"}], Entity["City", {"Mauga", "GagaEmauga", "Samoa"}], Entity["City", {"Apia", "Tuamasaga", "Samoa"}], Entity["City", {"IslandViewPiosBeach", "BayOfPlenty", "NewZealand"}], Entity["City", {"Mutis", "Choco", "Colombia"}], Entity["City", {"Kavieng", "NewIreland", "PapuaNewGuinea"}], Entity["City", {"Pimentel", "Lambayeque", "Peru"}], Entity["City", {"Palestina", "Guayas", "Ecuador"}]}

Since you're interested in the coastline, the following might be better:

GeoNearest[
    "City",
    Line @@ Entity["Ocean","PacificOcean"]["Polygon"],
    30
]

{Entity["City", {"IslandViewPiosBeach", "BayOfPlenty", "NewZealand"}], Entity["City", {"Mutis", "Choco", "Colombia"}], Entity["City", {"Kavieng", "NewIreland", "PapuaNewGuinea"}], Entity["City", {"Pimentel", "Lambayeque", "Peru"}], Entity["City", {"Palestina", "Guayas", "Ecuador"}], Entity["City", {"Cabra", "Panama", "Panama"}], Entity["City", {"Aberpura", "Papua", "Indonesia"}], Entity["City", {"AlvaroObregon", "Chiapas", "Mexico"}], Entity["City", {"Acacoyagua", "Chiapas", "Mexico"}], Entity["City", {"Santiago", "Veraguas", "Panama"}], Entity["City", {"BuenosAires", "Puntarenas", "CostaRica"}], Entity["City", {"Courtenay", "BritishColumbia", "Canada"}], Entity["City", {"Salem", "Oregon", "UnitedStates"}], Entity["City", {"Damascus", "Oregon", "UnitedStates"}], Entity["City", {"Roxana", "Limon", "CostaRica"}], Entity["City", {"LosChiles", "Alajuela", "CostaRica"}], Entity["City", {"Gizo", "Western", "SolomonIslands"}], Entity["City", {"Barranco", "BocasDelToro", "Panama"}], Entity["City", {"Limon", "Limon", "CostaRica"}], Entity["City", {"Karuizawa", "Nagano", "Japan"}], Entity["City", {"Cabanas", "Zacapa", "Guatemala"}], Entity["City", {"LeGrand", "California", "UnitedStates"}], Entity["City", {"Suwa", "Nagano", "Japan"}], Entity["City", {"WhiteRock", "BritishColumbia", "Canada"}], Entity["City", {"Ambato", "Tungurahua", "Ecuador"}], Entity["City", {"Buritica", "Antioquia", "Colombia"}], Entity["City", {"Oluta", "Veracruz", "Mexico"}], Entity["City", {"Abejorral", "Antioquia", "Colombia"}], Entity["City", {"Wasco", "Oregon", "UnitedStates"}], Entity["City", {"BarraDeSantaAna", "Tabasco", "Mexico"}]}

Since the Polygon and Line versions work, it might be worthwhile asking support why the plain Entity version doesn't work

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