17
$\begingroup$

If I add the water area and the land area of the world, I get the same number as if I asked for the total area of the world in the first place:

In[1]:= {CountryData["World", "WaterArea"] + CountryData["World", "LandArea"],
         CountryData["World", "Area"]}

Out[1]= {5.10066*10^8, 5.10066*10^8}

Now, if I add the area of all the countries, it does not add up to the total land area of the world:

In[2]:= {Total[CountryData[#, "Area"] & /@ CountryData[]], 
         CountryData["World", "LandArea"]}

Out[2]= {1.35936*10^8, 1.4912*10^8}

So my question is: are some countries missing? Are the ice caps to blame?

Improve this question
$\endgroup$
  • 5
    $\begingroup$ "Are the ice caps to blame?" - in a sense, yes; note that Antarctica is not in the list returned by CountryData[]. $\endgroup$ – J. M.'s ennui♦ Sep 4 '12 at 21:55
  • $\begingroup$ @J.M. Curiously CountryData["World", "LandArea"] - CountryData["Antarctica", "Area"] < Total[CountryData[#, "Area"] & /@ CountryData[]] $\endgroup$ – Dr. belisarius Sep 4 '12 at 21:56
  • $\begingroup$ Antarctica is not a sovereign country, but it is part of the world $\endgroup$ – rm -rf♦ Sep 4 '12 at 21:57
  • $\begingroup$ @belisarius: compare as well the output of Total[Flatten[CountryData[#, "Area"] & /@ CountryData["Continents"]]] with CountryData["World", "LandArea"]. Curious indeed. $\endgroup$ – J. M.'s ennui♦ Sep 4 '12 at 22:01
  • 2
    $\begingroup$ @wxffles No, we are still around and listed in CountryData. We are not part of Australia yet. :-) $\endgroup$ – Matariki Sep 5 '12 at 1:31
4
$\begingroup$

So both

CountryData["World", "LandArea"] - 
(CountryData["Antarctica", "LandArea"] +
 Total[CountryData[#, "LandArea"] & /@ CountryData[]])

and

CountryData["World", "LandArea"] - 
  Total[Flatten[CountryData[#, "LandArea"] & /@ CountryData["Continents"]]]

give $3.42636\times10^6 \text{ km}^2$ of area missing. That is approximately the area of current Arctic ice (I Googled it).

Also, there are some places that occupy a land area, but are not within any country (about maybe $10^4 \text{ km}^2$ in total); e.g., the Saudi–Iraqi neutral zone.

Improve this answer
$\endgroup$
  • $\begingroup$ Great! Let's reevaluate those commands in a year to see if they change. $\endgroup$ – Gustavo Delfino Oct 3 '12 at 14:01

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.