<p>A rough idea, using the Lambert Conformal image at the <a href="http://scitools.org.uk/cartopy/docs/v0.15/index.html" rel="nofollow noreferrer">Cartopy projection list</a> and Gimp:</p>

<p><a href="https://i.sstatic.net/Dxmj9.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/Dxmj9.png" alt="enter image description here"></a></p>

<p>The gold area should be the overlap.  So basically parts of South America with Indonesia and SE Asia... and Antarctica with the far northern islands of the northern hemisphere, plus a few smaller areas from islands like New Zealand and Hawaii and even smaller.</p>

<p>That assumes I did properly invert it.  To do so, I just vertically flipped the image, and offset it by 180 degrees.  Thinking that should be all that is needed.</p>

<p>So in the end it looks like it's not a lot of area at all.  Further exact statistics would take some GIS work (probably quicker than GIMP in the end!)  A central starting guess would be 8.5% (the 29% land cover squared), but particulars will make it a bit higher or lower.</p>

CC BY-SA 4.0
2018-05-14T01:32:21.613Z
Nice illustration! Clear and to the point.
Daniel Griscom
CC BY-SA 4.0
2018-05-14T07:12:31.077Z
Thanks a lot, this is very much what I was looking for but wouldnt have known how to achieve. (The now obviouse didn't occur to me: Staring out with the appropriately projected 2D map.)
BmyGuest
CC BY-SA 4.0
2018-05-15T21:49:10.040Z
keep in mind the areas in appear far larger than they really are as you get near the poles.
John
CC BY-SA 4.0
2018-05-15T23:23:51.153Z
@John, chose the map I did because I believe the listed file there is the [lambert cylindrical equal-area](https://en.wikipedia.org/wiki/List_of_map_projections) (though it wasn't absolutely clear... I'd rather have found a better image quality/reference, but was tough).  If it is equal area, believe those concerns shouldn't be an issue (note how the latitude lines are squished at the top/bottom, so it's not like Mercator, distorting polar areas), and thus those areas should prove directly proportional to the rest of the map.
JeopardyTempest
CC BY-SA 4.0
2018-05-17T01:21:11.707Z
Here's another: https://www.nzherald.co.nz/technology/news/article.cfm?c_id=5&objectid=11892400
Keith McClary
CC BY-SA 4.0
2018-05-17T04:38:58.680Z
@KeithMcClary Drat, where were you Saturday!!  Figured such much exist, but had no luck finding it.  Great link, much nicer detail... but glad at least to see it's at least confirmation.  Thanks!
JeopardyTempest
CC BY-SA 4.0
2022-12-03T11:40:40.063Z
@JeopardyTempest may I use your map overlay image as a header image for a social media account?
Lori
CC BY-SA 4.0
2022-12-04T02:30:38.920Z
@Lori absolutely :)  Keep in mind the original image is from https://scitools.org.uk/cartopy/docs/v0.15/index.html, so I don't know what attributions they require :)
JeopardyTempest
CC BY-SA 4.0
2018-05-13T20:41:41.993Z
2018-05-15T09:23:08.027Z
2018-05-15T09:23:08.027Z
JeopardyTempest
<p>Using the site <a href="https://www.antipodesmap.com/" rel="nofollow noreferrer">antipodesmap</a> one can quickly explore what the opposite point of the earth to any location would be. That is, the surface point connected to this point by a straight line through the centre of the earth.</p>

<p>It is easy to see that <em>most</em> land points have antipodes which lie somewhere in water, which made me wonder:</p>

<p><strong>How much land area (as a fraction of total land area) has antipodal land area?</strong> </p>

<p>And how would I best find this out? Can somebody produce a map of those areas, e.g. highlight those areas on a world map?</p>

<geography><mapping><cartography>
How much of Earth's land area has antipodal land area?
BmyGuest
# How much of Earth's land area has antipodal land area?

(Asked by: username_0 on 2018-05-13)

Using the site [antipodesmap](https://www.antipodesmap.com/) one can quickly explore what the opposite point of the earth to any location would be. That is, the surface point connected to this point by a straight line through the centre of the earth.

It is easy to see that *most* land points have antipodes which lie somewhere in water, which made me wonder:

**How much land area (as a fraction of total land area) has antipodal land area?**

And how would I best find this out? Can somebody produce a map of those areas, e.g. highlight those areas on a world map?

**Tags:** geography, mapping, cartography


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## 1 answers

### Answer by username_1 on 2018-05-13. Score: 8 | Accepted answer

A rough idea, using the Lambert Conformal image at the [Cartopy projection list](http://scitools.org.uk/cartopy/docs/v0.15/index.html) and Gimp:

[![enter image description here](https://i.sstatic.net/Dxmj9.png)](https://i.sstatic.net/Dxmj9.png)

The gold area should be the overlap. So basically parts of South America with Indonesia and SE Asia... and Antarctica with the far northern islands of the northern hemisphere, plus a few smaller areas from islands like New Zealand and Hawaii and even smaller.

That assumes I did properly invert it. To do so, I just vertically flipped the image, and offset it by 180 degrees. Thinking that should be all that is needed.

So in the end it looks like it's not a lot of area at all. Further exact statistics would take some GIS work (probably quicker than GIMP in the end!) A central starting guess would be 8.5% (the 29% land cover squared), but particulars will make it a bit higher or lower.

> **Comments:**
> **username_2**: Nice illustration! Clear and to the point.  
> **username_0**: Thanks a lot, this is very much what I was looking for but wouldnt have known how to achieve. (The now obviouse didn't occur to me: Staring out with the appropriately projected 2D map.)  
> **username_3**: keep in mind the areas in appear far larger than they really are as you get near the poles.  
> **username_1**: @username_3, chose the map I did because I believe the listed file there is the [lambert cylindrical equal-area](https://en.wikipedia.org/wiki/List_of_map_projections) (though it wasn't absolutely clear... I'd rather have found a better image quality/reference, but was tough).  If it is equal area, believe those concerns shouldn't be an issue (note how the latitude lines are squished at the top/bottom, so it's not like Mercator, distorting polar areas), and thus those areas should prove directly proportional to the rest of the map.  
> **username_4**: Here's another: https://www.nzherald.co.nz/technology/news/article.cfm?c_id=5&objectid=11892400  
> **username_1**: @username_4 Drat, where were you Saturday!!  Figured such much exist, but had no luck finding it.  Great link, much nicer detail... but glad at least to see it's at least confirmation.  Thanks!  
> **username_5**: @username_1 may I use your map overlay image as a header image for a social media account?  
> **username_1**: @username_5 absolutely :)  Keep in mind the original image is from https://scitools.org.uk/cartopy/docs/v0.15/index.html, so I don't know what attributions they require :)  

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