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From a previous question, around 40% of the northern hemisphere is land. Would there be a plane splitting the earth into two equal parts, where in one part there are more land than ocean?

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  • $\begingroup$ From a quick visual inspection with Google Earth I think the most likely candidate is a hemisphere including most of Africa, most of Eurasia, and either (Greenland) or (Indonesia and part of Australia). But that might struggle to reach 50%, as the Indian Ocean takes up a lot of it, so I'll be interested to see if somebody has a more authoritative answer! Another candidate might be a polar(ish) view centred over north-west Russia. It includes all of Eurasia,a bit more than half of Africa, and most of Canada/Alaska. $\endgroup$ – Semidiurnal Simon Jun 20 at 22:06
  • $\begingroup$ @SemidiurnalSimon - A point centered over northwest Russia would capture too much of the Pacific and would not capture all of Africa and North America. A point in western France does a better job, capturing almost all of Eurasia, all of Africa and North America, and a good chunk of South America. $\endgroup$ – David Hammen Jun 22 at 12:59
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The total land area of earth is approximately 29%. So, in order to have a hemisphere with more land than water, out of 29% of total land area we need to have at least 25% of it concentrated in that hemisphere.

Now for the ease of understanding, what does 25/29 of total land area means? It approximates to 86% of the total continental surface area.

Area of percentage

Asia (including the Middle East)- 30.0%

Africa - 20.3%

North America - 16.3%

South America - 12.0%

Antarctica - 8.9%

Europe - 6.7%

Australia (plus Oceania) - 5.2%

Now on analyzing this, it's possible to conclude you won't be able to get such a hemisphere using a plane along the longitudes.

If you try to create a hemisphere using a plane that cuts through 60˚S and 60˚N latitudes, you might be able to have most the major land together areas except Antartica and Australia and some parts of Africa in it. Still, it won't be enough to have more than half of that hemisphere with land covering it.

So, my conclusion is it's not possible to come up with such a hemisphere. :)

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I wrote a little Matlab script to estimate this approximatively. Here is the result: colour denotes the total land area inside the hemisphere centred on a particular surface point. The red point is the maximum. enter image description here

This gives me a maximum for the hemisphere centred on 1.7582°W longitude and 40.7692°N latitude, roughly in Guadalajara, Spain. If I calculated right this is 81% of all land, with 23.37% land area on the hemisphere (and 5.83% on the other hemisphere). So the answer to the question is no, there is no hemisphere with more land than ocean. There isn't even one with more than half land.

enter image description hereenter image description hereenter image description here

(Updated 2019-06-23 with higher resolution estimation, which moved the point south a bit.)

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  • $\begingroup$ You 43°20′N 1°06′W point is a bit south of the point designated in the wikipedia article on the land and water hemispheres, 47°13′N 1°32′W. That point appears to be based on 1891 maps and was determined without the aid of computers. $\endgroup$ – David Hammen Jun 22 at 12:53
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    $\begingroup$ +1 for the interesting process and answer, but in order to answer the question the answer should include which percent of that hemisphere is actually land (that is, the area of 81% of all land divided by the area of an hemisphere). $\endgroup$ – Pere Jun 22 at 13:33
  • $\begingroup$ Added the answer and ran my model at a higher resolution. The centre is still in Spain rather than France. I think one can quibble a fair bit about the correct way of doing this: I count large lakes as not-land, for example. $\endgroup$ – Anders Sandberg Jun 23 at 11:30

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