Human Factors of XR: Using Human Factors to Design XR Systems
Cartography
1. Ca rto g ra p he rs
a ffe c t ho w we
p e rc e ive
o ur
wo rld
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2. Representing the earth
A geographical map is a two-dimensional,
geometrically accurate representation of a three-
dimensional
space. Inevitably,
however,
distortion is
introduced when
a globe is made
to lay
flat.
This teacher uses a physical map
of Europe to explain his point.
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4. • A map projection is
Map any method used in
Projection
___________________
(mapmaking) to
represent the curved
surface of the earth on
a flat surface.
• This cannot be done
without some
___________________
• The mapmaker must
select the one best
suited to the needs,
reducing distortion of
the most important
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6. Mapmaker • Mapmakers and
mathematicians
s have devised almost
________________
ways to project the
image of the globe
onto paper.
• Every projection has
its own set of
advantages and
disadvantages.
There
is no
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“______________"
7. • Flat maps can be more
Good Uses useful than globes in
many situations:
of Flat Maps
• Maps are more
compact and easier to
store.
• They are viewed easily
on computer displays.
• Maps can show larger
portions of the earth's
surface at once.
• These useful traits of
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flat maps motivate the
development of map
8. The Problem • Every flat map
misrepresents the
with Flat surface of the Earth in
Maps some way.
• No map can rival a
_______________in
truly representing the
surface of the entire
Earth
• Since the world is a
sphere, and a globe is
a sphere, a perfect
representation can be
made.
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10. Types of map projections
Each introduces some error inherent when three-
dimensional sphere is flattened into two dimensions.
• Mercator
• Mollweide
• Robinson
• Peters
• Polar
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11. Which projection?
The earth is
round. The
challenge of
any world map
is to represent
a round earth
on a flat
surface.
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12. Globes and Map Projections
• Projection: a way of showing the earth
on a flat surface.
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14. Cylindrical Projection: is based on a cylinder
tangent to the equator. Good for equatorial
regions but greatly distorted at high latitudes.
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15. Mercator projection
Though the Mercator projection is particularly
good for navigation, it becomes increasingly distorted
toward the poles, resulting in areas appearing much
larger than they actually are.
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16. • This map makes areas
Mercator
Projection near the ____________
look bigger than they
really are.
• Example, Greenland
looks bigger than it
really is. Here, it is
larger than S.
America, but in real
life, it is less than half
the size.
• This is because, on a
globe, the lines of
longitude meet at the
poles, but on this type,
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21. • The Peters
Peter’s Projection was
created in
Projection ______________ by
Dr. Arno Peters to
address some of
the distortions of
existing maps
• Problem: One
square inch
anywhere on this
map represents an
equal number of
square miles.
Distorts the shape
in some cases.
• Example: Africa
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22. The Robinson projection is based on tables
of coordinates. The projection distorts shape,
area, scale, and distance in an attempt to
balance the errors of projection properties.
The Robinson projection
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23. Robinson • Presented by Dr.
Projection Arthur H. Robinson in
__________________.
• Today, many
geographers believe
this to be the best
world map available. It
has been called so by
National Geographic
• While the Robinson
projection does distort
the globe a little,
(Check out
Antarctica), it shows
the sizes and shapes
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of most countries
25. • By creating
Interrupted
Projection _____________ in the
picture of the world,
mapmakers showed
the size and shape of
most of the land quite
accurately.
• Problems:
• The gaps make it
impossible to figure
distances correctly
• You could not use
this kind of map to
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chart a journey
across the ocean.
43. Prime Meridian:
• 0° longitude line that runs from the
north pole to the south pole
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44. Different types of Maps
• Political Map: shows location of
countries, states, and provinces and
boundary lines separation
governments
• Physical Map: shows physical features
of an area
• Mountains, plains, valleys, etc
• Economic map: can see that locations
of natural resources, industrial areas,
farmlands, and fishing areas
• Travel or transportation map: also
known as a road map
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45. Landsat
A series of satellites that
can photograph the
entire earth in 16 days.
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46. Global Positioning Systems (GPS)
This system uses a series of 24 satellites called
the Navstars to beam information to earth about
an object and its location of the earth’s surface.
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47. Atlas technology
“Like a huge piece
of orange peel that
refuses to be
flattened without
tearing at the
edges, the globe
cannot be forced
into two
dimensions
without distortion.
But that distortion
can now be
minimised “
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There are literally thousands of map projections. Each has certain strengths and corresponding weaknesses. Choosing among them is an exercise in values clarification: you have to decide what's important to you.
This one of the oldest and most common projections
The Mollweide Equal Area projection preserves the relative area of landforms.
but it looks like someone hung their laundry out to dry
A great circle path is the shortest path on the surface of a sphere between two points on that sphere.