Quirks in Mathematica’s administrative division data for Mexico

If you ask Mathematica for a list of Mexican states via

 CountryData["Mexico", "RegionNames"]

you will get a list of strings:

 "Aguascalientes", "Baja California", ..., "Zacatecas"}

However, when you try to turn this into a list of objects representing these states via

 states = Entity["AdministrativeDivision", {#, "Mexico"}] & /@ CountryData["Mexico", "RegionNames"]

something strange happens. Some items in the list are turned into useful objects, and some are uninterpreted symbols.

For example, Aguascalientes is recognized as an administrative division, but Baja California is not. It recognizes Oaxaca but not Nuevo Leon. The pattern is that states with a space are not recognized. There is an inconsistency in Mathematica: output names do not always match input names. To create the object representing Baja California, you need to pass in the string BajaCalifornia with no space.

 Entity["AdministrativeDivision", {"BajaCalifornia", "Mexico"}]

OK, so let's remove spaces before we try to create a list of geographic objects.

 names = StringReplace[#, " " -> ""] & /@ CountryData["Mexico", "RegionNames"]

This mostly works, but it trips up on Mexico City. The output name for the region is Ciudad de Mexico, but Mathematica does not recognize CiudaddeMexico as an administrative division. Mathematica does recognize MexicoCity as the name of a city but not as the name of an administrative division.

Changing CiudaddeMexico to MexicoCity in the list of names did not fix the problem. But when I directly edited the list of state objects by replacing the uninterpreted value with the output running

 Entity["AdministrativeDivision", {"MexicoCity", "Mexico"}]

by itself everything worked. Then I was able to find a Traveling Salesman tour as in earlier posts (Africa, Americas, Eurasia and Oceania, Canada).

Traveling Salesman tour of Mexico

The tour is

1. Baja California
2. Baja California Sur
3. Sinaloa
4. Durango
5. Zacatecas
6. Aguascalientes
7. Nayarit
8. Jalisco
9. Colima
10. Michoacan
11. Mexico
12. Mexico City
13. Morelos
14. Guerrero
15. Oaxaca
16. Chiapas
17. Tabasco
18. Campeche
19. Quintana Roo
20. Yucatan
21. Veracruz
22. Puebla
23. Tlaxcala
24. Hidalgo
25. Queretaro
26. Guanajuato
27. San Luis Potosi
28. Tamaulipas
29. Nuevo Leon
30. Coahuila
31. Chihuahua
32. Sonora

The tour is 8,343 kilometers.

The post Quirks in Mathematica's administrative division data for Mexico first appeared on John D. Cook.