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Chapter 2 Where in the Geospatial World Are You?
From 7.5 degrees west longitude to 7.5 degrees east longitude is one time zone,
7.5 to 22.5 degrees longitude is a second time zone, and so on. Following these
sections of longitude around the world, the east coast of the United States is five
time zones to the west of the Prime Meridian, thus making the time in places
like New York or Boston five hours behind the time in Greenwich. America’s
west coast lies in the region eight time zones to the west of the Prime Meridian
(and three to the west of the United States east coast), thus making the time in
San Francisco eight hours behind Greenwich (or three hours behind New York).
However, take a closer look at Figure 2.3 and you’ll see that time zones
don’t exactly follow the lines of longitude. Some political or geographic
boundaries cause some areas to entirely be in one time zone when the area
may straddle two zones, or some areas may be in one zone or another despite how the lines of longitude lie. Other countries, such as China, adopt one
time measurement for the entire country, despite China’s geography crossing
multiple time zones. The International Date Line marks the division between
24-hour periods and splits one day from another, but it also bends to accommodate some geography and islands to be in one time zone or another, rather
than strictly follow the line of the 180th meridian.
How Can Real-World Data Be Translated
onto a Two-Dimensional Surface?
All of these measurements are being done on a three-dimensional world
but are somehow being translated onto a two-dimensional surface (like a
piece of paper or a computer screen) for ease of use. A map projection is a
translation of coordinates and locations from their places in the real world
to a flat surface, and it is necessary to be able to use this geospatial data.
The biggest problem with a map projection is that not everything is going
Let’s face it, these days we’re living in a digital
world—road maps, road directions, and property
maps are all available with a few clicks of a mouse in
digital form. With everything available digitally (and
more portable and accessible with wireless Internet
access via laptops and phones), is there a need for
printed maps? Do you really need to carry around a
paper map version of the road network in Los Angeles,
California, or will a mapping app on your smartphone
suffice to find where your location is and get you
where you want to go? In the same vein, are paper
map collections at universities or libraries relics of
the past or still useful resources? When would having access to such a collection be necessary?
When driving a long distance is it necessary to
have a printed map of the area you’re traveling
through when you’ve got GPS, satellite maps, and
Internet mapping capabilities? If yes, what’s a situation in which it would be necessary, and if no, why
are printed maps still available?
Do You Really Need Printed Maps in a Digital World?
Thinking Critically with Geospatial Technology 2.1
map projection the
translation of locations
on a three-dimensional
(3D) Earth to a twodimensional (2D)
surface.
Chapter 2 Where in the Geospatial World Are You?
From 7.5 degrees west longitude to 7.5 degrees east longitude is one time zone,
7.5 to 22.5 degrees longitude is a second time zone, and so on. Following these
sections of longitude around the world, the east coast of the United States is five
time zones to the west of the Prime Meridian, thus making the time in places
like New York or Boston five hours behind the time in Greenwich. America’s
west coast lies in the region eight time zones to the west of the Prime Meridian
(and three to the west of the United States east coast), thus making the time in
San Francisco eight hours behind Greenwich (or three hours behind New York).
However, take a closer look at Figure 2.3 and you’ll see that time zones
don’t exactly follow the lines of longitude. Some political or geographic
boundaries cause some areas to entirely be in one time zone when the area
may straddle two zones, or some areas may be in one zone or another despite how the lines of longitude lie. Other countries, such as China, adopt one
time measurement for the entire country, despite China’s geography crossing
multiple time zones. The International Date Line marks the division between
24-hour periods and splits one day from another, but it also bends to accommodate some geography and islands to be in one time zone or another, rather
than strictly follow the line of the 180th meridian.
How Can Real-World Data Be Translated
onto a Two-Dimensional Surface?
All of these measurements are being done on a three-dimensional world
but are somehow being translated onto a two-dimensional surface (like a
piece of paper or a computer screen) for ease of use. A map projection is a
translation of coordinates and locations from their places in the real world
to a flat surface, and it is necessary to be able to use this geospatial data.
The biggest problem with a map projection is that not everything is going
Let’s face it, these days we’re living in a digital
world—road maps, road directions, and property
maps are all available with a few clicks of a mouse in
digital form. With everything available digitally (and
more portable and accessible with wireless Internet
access via laptops and phones), is there a need for
printed maps? Do you really need to carry around a
paper map version of the road network in Los Angeles,
California, or will a mapping app on your smartphone
suffice to find where your location is and get you
where you want to go? In the same vein, are paper
map collections at universities or libraries relics of
the past or still useful resources? When would having access to such a collection be necessary?
When driving a long distance is it necessary to
have a printed map of the area you’re traveling
through when you’ve got GPS, satellite maps, and
Internet mapping capabilities? If yes, what’s a situation in which it would be necessary, and if no, why
are printed maps still available?
Do You Really Need Printed Maps in a Digital World?
Thinking Critically with Geospatial Technology 2.1
map projection the
translation of locations
on a three-dimensional
(3D) Earth to a twodimensional (2D)
surface.