Introduction to Maps

Cartography The art and science of making maps, including data compilation, layout, and design. Also concerned with the interpretation of mapped patterns. A stone tablet found in a cave in Abauntz in the Navarra region of northern Spain is believed to contain the earliest known representation of a landscape.

How do we make maps? Satellite Images Aerial Photographs - vertical - oblique Sonar Surveying Field Study

oblique vertical

Why Make Maps?

Maps A map is a two dimensional description of a specific area of land Maps describe in a visual or graphic format certain key features of the territory being examined Examples: A road map of Nova Scotia shows many of the important roads and how they interconnect, as well as the locations of towns and cities, and other popular destinations Other maps might show the distribution of birds along the wetlands of the Great Lakes, or the distribution of human populations throughout the world

Maps Maps are important tools and are indispensable to geographers They help geographers understand in a visual way important things about the surface of the Earth Examples of how Geographers use Maps: Where do evergreens grow, where are volcanoes actively erupting, and where are trout most likely to be found

What are the key components of a map? Legend Scale Bearing Grid References Contour Lines Land/Water distinction

Maps Are Not Perfect Maps have been used by humans for hundreds of years. As technology has improved, so have the quality and accuracy of maps. Ancient maps were usually drawn by explorers. It was impossible at that time for anyone to leave the Earth and look down at the huge continents below. All they could do was walk around the different land formations, and then do their best to draw what they thought the land probably looked like

The Earth is ROUND!

Maps Are Not Perfect In the modern world, our ability to view and map the Earth is much improved However, even today it is impossible to draw a flat map that is 100% accurate This is due to the impossibility of recreating the surface of a round planet on a flat map The smaller an area that a map represents, the more accurate that map will be

Cylindrical Projection A cylindrical projection map is the most common type of map that we see. Imagine placing the movie screen around the globe in a cylinder shape. The projection that results is depicted in this image. Notice that areas close to the equator have very little distortion. However, the closer to the poles that one travels, the more distorted the map becomes

Cylindrical Projection In this example, Greenland appears to be many times larger than it really is.

Conic Projection A conic projection map is created by placing a cone shaped screen on a globe The resulting projection is more accurate than the cylindrical projection map discussed above However, the further we travel down the map, the more distorted and less accurate the map becomes

Plane Projection A plane projection is created by placing an imaginary screen directly above or below a globe The image that would result is called a plane projection This type of map projection is not commonly used

Interrupted Projection There are many different types of interrupted projection maps. These types of maps try to depict the continents as accurately as possible by leaving blank space in the less important areas of the map, such as in the oceans

Shape Versus Size – Conformality Versus Equivalency All map projections must consider which of these two factors are more important: Depicting the accurate sizes of objects on the map Depicting accurate shapes of these objects? The challenge is that you cannot have both. The more accurately you depict shape, the less accurate will be your depiction of size, and vice versa.

A map which portrays shape accurately is called a conformal map Conformal maps are useful in that they help us understand the true shape of the items on the map. A drawback of a conformal map is that it tends to get quite distorted, especially towards the top and bottom of the map This creates problems with scale; it may be accurate near the equator, but the further one travels form the equator, the less accurate the scale becomes

A map which portrays size accurately is referred to as an equivalent map Equivalent maps are very useful because they accurately show the size of objects on the map This means that no matter what part of the map we examine, the scale will remain accurate However, the drawback of equivalent maps is that the shape of objects is distorted

Hybrid Maps Many maps are neither entirely conformal nor entirely equivalent By blending both conformality and equivalency, we can create a map that balances the distortion of both size and shape Some map projections are entirely conformal, while others are entirely equivalent It is impossible for a map to be both conformal and equivalent but many maps are a hybrid between conformal and equivalent

Mercator Projection Cylindrical map projection Useful for navigation because it maintains accurate direction Famous for their distortion in area that makes landmasses at the poles appear oversized

Mercator Projection

Peters Projection Cylindrical map projection Attempts to retain all the accurate sizes of all the world’s landmasses Sometimes used as a political statement- that we should refocus our attention to the tropics, home to large landmasses and many of the world’s poorest countries.

Peters Projection

Fuller Projection Maintains the accurate size and shape of landmasses Completely rearranges direction such that the four cardinal directions (north, south, east, and west) no longer have any meaning.

Fuller Projection

Robinson Projection Attempts to balance several possible projection errors. Does not maintain completely accurate area, shape, distance, or direction, but it minimizes errors in each. Used by National Geographic

Robinson Projection

Azimuthal Projection Planar Formed when a flat piece of paper is placed on top of the globe and, as described earlier, a light source projects the surrounding areas onto the map. Either the North Pole or South Pole is oriented at the center of the map which gives the viewer the impression of looking up or down at the earth.

Azimuthal Projection