!!

Guests can now post!

Welcome to Intelligent Answers.  As a guest, you are now able to post a question, subject to getting through our spam-bot filters.  However, if you want to answer any questions, you will need to register.  Thanks for visting!  (BTW - guests cannot post links, and if you post spam, we will block your IP and report you to every spam protection site we can find - we work hard to keep this site spam free for the benefit and enjoyment of our members!)

Author Topic: If, as I have been told, Africa represents over 20% of the world's land area, th  (Read 1470 times)

Offline P-Kasso2

  • Awaiting inspiration.
  • PK unique
  • University Councillor
  • *
  • Thank You
  • -Given: 55
  • -Receive: 164
  • Posts: 12325
  • Helpfulness: 214
  • January 2011 prize-quiz winner.



If, as I have been told, Africa represents over 20% of the world's land area, then why doesn't Africa look larger on a world map? Is this Western capitalist plot?
"I live in hope"

Offline siasl

  • Founder member who you can't insult as I'm too ignorant.
  • Administrator
  • Chancellor
  • *****
  • Thank You
  • -Given: 122
  • -Receive: 85
  • Posts: 5306
  • Helpfulness: 129
  • Intelligence is soluble in alcohol <hic>
The answer is probably both yes and no, but the roots of the answer lie in these things called "projections".

Now, maps are flat pieces of paper (generally) and while everyone believed that the world was flat, this would have been hunky dory. If this had been true, then presumably someone would have eventually discovered the edge of the world, and we could have a piece of paper precisely the same shape as the world to colour in with blues & greens & browns, and we'd have a nice precise map.

Unfortunately, the world is more like a squished sphere, and this doesn't unravel into a flat rectangle like the paper-mills produce and is nice and convenient for sticking in books. Instead, you either have to cut it into funny shapes (and you'll still have issue, but they will result in less glaring errors), or you have to stretch it out.

The typical projection is to make a cut in a straight line fro,mm the north pole to the south pole and call that cut the left and right edge of your sheet of paper. The top and bottom edge become the poles - along their entire edge as we are stretching a "point" along these edges.

The impact of this is that all the stuff close to the poles gets stretched out of proportion in terms of physical size if you were to assume a constant scale across the sheet of paper. To "fix" this, you have to have a variable scale across the map.

This can be demonstrated in reverse with a simple balloon and marker pen experiment. Inflate the balloon, draw a square on it near the "equator" where the material is stretched the most and another one the same size near the "pole" where the material is not stretched much. Then slowly deflate the balloon (or pop it, but you may lose the pieces). Now are the squares the same size/shape?

In reality, there's a standards body that has chopped up the world map into different regions of latitude and longitude, and defined a mathematical equation that maps the lat/long to an x/y coordinate in metres. And this equation is accurate to a given tolerance (typically a metre or two across a reasonably large swathe of the map), but is only valid for that zone.

Offline antonymous

  • Perpendicular Galileo Galilei
  • Founder
  • Marie Curie
  • *
  • Thank You
  • -Given: 92
  • -Receive: 133
  • Posts: 2016
  • Helpfulness: 168
  • "We're all bankers now!"
    • Antonymous2011 Flickr Page
Following Siasls excellent answer,

Here is a more realistic view of the world which gets round the distortion of themercator projection. It is a polar projection centred on the North pole.
You can clearly see the huge (20/25% of total land mass) size of Africa.
                                                                             
« Last Edit: 24 April, 2015, 03:41:57 PM by antonymous »
“Sometimes the questions are complicated and the answers are simple. Sometimes it'svice versa"

Offline P-Kasso2

  • Awaiting inspiration.
  • PK unique
  • University Councillor
  • *
  • Thank You
  • -Given: 55
  • -Receive: 164
  • Posts: 12325
  • Helpfulness: 214
  • January 2011 prize-quiz winner.
Thanks both of you. Two excellent answers. I see what you mean.

But also look how small the USA has become in Ant's more accurate polar projection map! Only a quarter of the size bigger than Australia.

I told you so, our current maps, where the USA looks enormous....it's all a diabolical Western capitalist plot to keep down the oppressed African nations!
« Last Edit: 24 April, 2015, 05:19:42 PM by P-Kasso2 »
"I live in hope"