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If I add the WaterArea and the LandArea 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 LandArea 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?

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

up vote 4 down vote accepted

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.

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Great! Lets reevaluate those commands in a year to see if they change. –  Gustavo Delfino Oct 3 '12 at 14:01
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