How do I remove certain results from CityData[{Large, "city"}]

Questions
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1

Following plots the population for cities above 100,000 residents.

Graphics[{Gray, CountryData["USA", "Polygon"], Opacity[0.5, Blue], 
  Tooltip[Disk[Reverse[CityData[#, "Coordinates"]], 
      CityData[#, "Population"]/10.^6], {CityData[#, "Name"], 
      CityData[#, "Population"]}] & /@ CityData[{Large, "USA"}]}, 
 ImageSize -> 900]

900×414 19.8 KB

How can I remove certain cities from the result?
(trying to delete the data from Anchorage and Honolulu, pointed by the two arrows in the above picture)

Also, is there a way to change the threshold for the CityData[{Large,“USA”}]? The option “Large” is set to 100,000.

Thank you in advance!

2

merely clicking the entity to delete and pressing the delete button is a one-time workaround. XD

But I’m looking for a solution that I could include in the code.

900×393 26.1 KB

3

I have two approaches:

The first (and I think best) is to replace

CityData[{Large, "USA"}]

with

DeleteCases[CityData[{Large, "USA"}], {_, "Alaska" | "Hawaii", _}]

to ignore cities in Alaska and Hawaii.

The second is to give a specific plot range to the graphic, such as:

PlotRange -> {{-127, -65}, {23, 51}}

that will roughly encompass the continental United States (plus the size of the disks.)

4

I realized I have not thanked you for the solution(s)!!

Thank you so much! :smiley:

5

{Large, country} syntax used by CityData has a fixed threashold of 100,000 people. Also, notice that

CountryData["USA", "LargestCities"]

is fixed at the top 100 cities by population.

To use your own population threshold, apply a filter to the list of fully quilified city names. Then use that new list for pulling up all the other properties. This particular approch is not the only way and it is not paritcularly fancy, but it does the job in stages, so we can see what is going on.

usCities = CityData[{All, "UnitedStates"}];
allUSPop = CityData[#, "Population"] & /@ usCities;
togehter = Transpose@{usCities, allUSPop};
threshold = 200000;
filterPop = Select[togehter, (#[[2]] >= threshold &)];
filterUSCities = filterPop[[All, 1]];

Either of these approches can be combined with the “Alaska” | “Hawaii” exclusion list given by Brett, directly in your existing code,

DeleteCases[CountryData["USA", "LargestCities"], {_, "Alaska" | "Hawaii", _}]
DeleteCases[filterUSCities, {_, "Alaska" | "Hawaii", _}]