1
00:00:00,000 --> 00:00:01,933
♪

2
00:00:01,933 --> 00:00:03,263
Alright, here we go!

3
00:00:04,064 --> 00:00:07,198
If I want to turn this globe 
into a flat map,

4
00:00:07,198 --> 00:00:09,250
I’m going to have to cut it open.

5
00:00:17,008 --> 00:00:21,512
In order to get this globe to look 
anything close to a rectangle lying flat,

6
00:00:21,512 --> 00:00:24,032
I've had to cut it in several places.

7
00:00:24,032 --> 00:00:28,256
I've had to stretch it so the 
countries are starting to look all wonky.

8
00:00:28,256 --> 00:00:34,034
And even still, it's almost impossible 
to get it to lay flat.

9
00:00:34,034 --> 00:00:37,294
And that right there is the eternal 
dilemma of map makers.

10
00:00:37,904 --> 00:00:39,989
The surface of a sphere cannot be

11
00:00:39,989 --> 00:00:43,017
represented as a plane without some form
of distortion.

12
00:00:43,017 --> 00:00:46,239
That was mathematically proved,
by this guy, a long time ago.

13
00:00:46,239 --> 00:00:47,578
Since around 1500s,

14
00:00:47,578 --> 00:00:50,687
mathematicians have set about
creating algorithms that

15
00:00:50,687 --> 00:00:53,100
would translate the globe 
into something flat.

16
00:00:53,100 --> 00:00:55,723
And to do this, they use a 
process called projection.

17
00:00:56,173 --> 00:00:58,862
Popular rectangular maps use a cylindrical
projections.

18
00:00:59,042 --> 00:01:03,401
Imagine putting a theoretical cylinder
over the globe and projecting each of the

19
00:01:03,401 --> 00:01:07,360
points of the sphere onto 
the cylinder’s surface.

20
00:01:07,036 --> 00:01:10,595
Unroll the cylinder, and you have a flat,
rectangular map.

21
00:01:10,975 --> 00:01:13,939
But you could also project the globe onto
other objects,

22
00:01:13,939 --> 00:01:16,974
and the math used by map makers 
to project the globe

23
00:01:16,974 --> 00:01:20,440
Will effect what the map
looks like once it’s all flattened out.

24
00:01:20,161 --> 00:01:25,027
And here’s the big problem: Every one of
these projections comes with trade offs in

25
00:01:25,081 --> 00:01:28,426
shape, distance, direction and land area.

26
00:01:28,425 --> 00:01:30,719
Certain map projections can 
be either misleading

27
00:01:30,719 --> 00:01:32,901
or very helpful 
depending on what

28
00:01:32,901 --> 00:01:34,280
you are using them for.

29
00:01:34,028 --> 00:01:35,067
Here’s an example.

30
00:01:35,067 --> 00:01:37,833
This map is called the 
Mercator projection.

31
00:01:38,013 --> 00:01:41,031
If you’re American, you probably studied 
this map in school.

32
00:01:41,031 --> 00:01:43,336
It’s the projection Google Maps uses.

33
00:01:43,336 --> 00:01:46,408
The Mercator projection is popular 
or a couple of reasons.

34
00:01:46,438 --> 00:01:49,179
First, it generally preserves the 
shape of the countries.

35
00:01:49,179 --> 00:01:53,707
Brazil on the globe has the same shape as
Brazil on the Mercator projection.

36
00:01:53,707 --> 00:01:54,707
[Ding]

37
00:01:54,707 --> 00:01:58,100
But the real purpose of the Mercator
projection was navigation --

38
00:01:58,100 --> 00:02:01,418
it preserves direction,
which is a big deal if you are

39
00:02:01,418 --> 00:02:03,749
trying to navigate
the ocean with only a compass.

40
00:02:03,749 --> 00:02:06,364
It was designed so that a line drawn 
between two points

41
00:02:06,364 --> 00:02:08,138
on the map 
would provide the exact

42
00:02:08,138 --> 00:02:11,869
angle to follow on a compass to 
travel between those points.

43
00:02:12,039 --> 00:02:15,967
If we go back to the globe, you can 
see that this line is not shortest route.

44
00:02:15,967 --> 00:02:20,235
But it provides a simple, reliable way to
navigate across the ocean.

45
00:02:20,371 --> 00:02:23,698
Gerardus Mercator, who created the 
projection in the 16th century,

46
00:02:23,698 --> 00:02:27,189
was able to preserve direction 
by varying the distance between

47
00:02:27,189 --> 00:02:29,852
the latitude lines 
and also making them straight.

48
00:02:30,002 --> 00:02:32,079
Creating a grid of right angles.

49
00:02:32,519 --> 00:02:34,294
But that created some other problems.

50
00:02:34,354 --> 00:02:37,277
Where Mercator fails is its representation
of size.

51
00:02:37,277 --> 00:02:39,856
Look at the size of Africa
as compared to Greenland.

52
00:02:39,856 --> 00:02:42,321
On the Mercator map they look 
about the same size.

53
00:02:42,321 --> 00:02:45,393
But if you look at a globe for 
Greenland’s true size,

54
00:02:45,393 --> 00:02:48,001
you’ll see it’s way 
smaller than Africa

55
00:02:48,431 --> 00:02:51,266
By a factor of 14 in fact.

56
00:02:52,196 --> 00:02:55,594
If we put a bunch of dots, on the globe, 
that are all the same size,

57
00:02:55,594 --> 00:02:58,125
and then we projected that 
onto the Mercator map

58
00:02:58,125 --> 00:02:59,388
we would end up with this.

59
00:02:59,388 --> 00:03:02,315
The circles retain their round shape, 
but are enlarged

60
00:03:02,315 --> 00:03:04,043
as they get closer to the poles.

61
00:03:04,043 --> 00:03:08,053
One modern critique of this is that the 
distortion perpetuates imperialist

62
00:03:08,053 --> 00:03:11,612
attitudes of European domination 
over the southern hemisphere

63
00:03:11,612 --> 00:03:16,008
"The Mercator projection has fostered 
European imperialist attitudes for centuries

64
00:03:16,008 --> 00:03:18,554
and created a ethnic bias 
against the third world."

65
00:03:18,964 --> 00:03:19,833
"Really?"

66
00:03:19,894 --> 00:03:23,162
So if you want to see a map that more 
accurately displays land area,

67
00:03:23,162 --> 00:03:26,540
you can use the Gall-Peters projection,

68
00:03:26,540 --> 00:03:27,674
this is called an equal-area map.

69
00:03:28,244 --> 00:03:29,819
Look at Greenland and Africa now.

70
00:03:29,819 --> 00:03:31,390
The size comparison is accurate.

71
00:03:31,395 --> 00:03:33,198
Much better than the Mercator.

72
00:03:33,198 --> 00:03:37,098
but it’s obvious now that the country 
shapes are totally distorted.

73
00:03:37,098 --> 00:03:41,016
Here are the dots again so we can see how
the projection preserves area

74
00:03:41,016 --> 00:03:43,835
while totally distorting shape.

75
00:03:45,034 --> 00:03:47,191
Something happened in the late 60s

76
00:03:47,191 --> 00:03:49,449
that would change the whole 
purpose of mapping

77
00:03:49,449 --> 00:03:51,325
and the way we think about projections.

78
00:03:51,325 --> 00:03:55,320
Satellites orbiting our planet started 
sending location and navigation data

79
00:03:55,320 --> 00:03:57,923
to little receiver units all 
around the world.

80
00:03:57,927 --> 00:03:58,957
[Rocket blasting off]

81
00:03:58,957 --> 00:04:02,369
"Today orbiting satellites of the 
Navy Navigation Satellite System

82
00:04:03,332 --> 00:04:07,612
provide round the clock, ultra precise 
position fixes, from space,

83
00:04:07,612 --> 00:04:11,109
to units everywhere in 
any kind of weather."

84
00:04:12,935 --> 00:04:16,406
This global positioning system 
wiped out the need for paper maps

85
00:04:16,406 --> 00:04:18,168
as a means of navigating

86
00:04:18,168 --> 00:04:19,488
both the seas and the sky.

87
00:04:19,488 --> 00:04:23,684
Map projection choices became less about 
navigational imperatives and more about

88
00:04:23,684 --> 00:04:25,820
aesthetics, design,and presentation

89
00:04:26,076 --> 00:04:30,521
The Mercator map, that once vital tool of 
pre-GPS navigation,

90
00:04:30,521 --> 00:04:32,539
was shunned by cartographers who

91
00:04:32,539 --> 00:04:33,980
now saw it as misleading.

92
00:04:34,074 --> 00:04:38,296
But even still, most web mapping tools 
like Google Maps, use the Mercator.

93
00:04:38,731 --> 00:04:42,609
This is because the Mercator’s
ability to preserve shape and angles makes

94
00:04:42,609 --> 00:04:46,789
close-up views of cities more accurate -- 
a 90 degree left turn on the map

95
00:04:46,789 --> 00:04:50,000
is a 90 degree left turn on 
the street you’re driving down.

96
00:04:50,168 --> 00:04:52,945
The distortion is minimal when 
you are close up.

97
00:04:52,965 --> 00:04:57,062
But on a world map scale, 
cartographers rarely use the Mercator.

98
00:04:57,610 --> 00:04:59,576
Most modern cartographers have 
settled on a

99
00:04:59,576 --> 00:05:02,229
variety of non-rectangular 
projections that

100
00:05:02,229 --> 00:05:05,380
split the difference between distorting
either size or shape.

101
00:05:05,380 --> 00:05:09,215
In 1998 The National Geographic Society 
adopted The Winkel-Tripel projection

102
00:05:09,215 --> 00:05:10,910
because of it’s pleasant balance

103
00:05:10,910 --> 00:05:12,866
between size and shape
accuracy.

104
00:05:13,155 --> 00:05:16,043
But the fact remains, that there is 
no one right projection.

105
00:05:16,043 --> 00:05:19,536
Cartographers and mathematicians have 
created a huge library

106
00:05:19,536 --> 00:05:21,230
of available projections.

107
00:05:21,230 --> 00:05:23,446
Each with a new perspective on the planet.

108
00:05:23,446 --> 00:05:25,207
And each useful for a different task.

109
00:05:25,207 --> 00:05:27,649
The best way to see the Earth
is to look at a globe.

110
00:05:27,649 --> 00:05:31,670
But as long we use flat maps, 
we'll have to deal with the trade-offs

111
00:05:31,670 --> 00:05:32,276
of projections,

112
00:05:32,276 --> 00:05:33,652
And just remember:

113
00:05:33,652 --> 00:05:35,050
there’s no right answer.

114
00:05:37,609 --> 00:05:40,538
If you yourself want to poke fun at 
the Mercator projection

115
00:05:40,538 --> 00:05:44,350
You can do so, 
by going to thetruesize.com

116
00:05:44,350 --> 00:05:48,364
Which is a fun tool that allows you to 
drag around whatever country you want

117
00:05:48,364 --> 00:05:51,758
around the map and see how it 
is distorted depending on where it is.

118
00:05:51,758 --> 00:05:54,700
I also want to say a big thanks, 
to Mike Bostock

119
00:05:54,700 --> 00:05:56,342
who's open source project 
on map projections,

120
00:05:56,342 --> 00:05:57,996
was a huge help in this video.

121
00:05:57,996 --> 00:06:02,436
I'll put a link to both of those things 
down in the description.