Maps and Map Projections

Map Scale: Types

1. Fraction (Graphic) Scale: 1//24,000 2. Ratio: 1:24,000 3. Written (Verbal) Scale*: "I inch equals 1 mile." *This is safest because the map will "shrink" or "grow" if it is altered. For example, if you photocopy a map and increase or decrease its size when copying, the printed scale will not be accurate any longer.

Map Projections

A map projection is a way to represent the round earth on a flat surface. Maps are used as reference and communication tools. Note: No map projection is as accurate as a globe.

Mashup

A mashup is a combination of vector and raster data. Examples of useful mashups include traffic tie-ups, gas prices in an area, or current location of commercial flights

Raster Data

A representation of a pixelated area divided into cells or squares wherein each unit is filled in with landform information, such as agricultural land, forest areas, marshes, mountains, and etc.

Vector Data

A representation of the world using points, such as cities, or lines, such as borders, waterways or roadways.

Global Information System (GIS)

GIS is a system designed to capture, store, manipulate, analyze, manage, and present all types of spatial or geographical data. This type of satellite-driven analysis can show spatially display, for instance, environmental erosion, drought, famine, and etc.

Types of Map Projections: Conic Projection

Imagine a cone placed over part of the globe. This shows small east-west areas in the middle latitudes. Distance and direction are fairly accurate.

Map Scale

In cartography (science of map making), scale refers to the ratio between the size of area on a map and the actual size of that same area on earth's surface. In more general terms, scale refers to the size of the area studied, from local to global.

Types of Map Projections: Sinsuoidal Projection

Parallels and central meridians are straight lines. Shapes are accurate in the center but distorted toward the edge. There are no lines of true distance.

The difference between place and location

Place: a specific point on earth distinguished by particular characteristics (think: NorCal or the "South") Location: position that something occupies on the earths surface (latitude and longitude)

Types of Map Projections: Robinson Projection

Shapes near the North and South poles are flattened. Continents appear similar to a globe projection.

Types of Map Projections: Azimuthal or Polar Projection

These are most commonly used for air navigation. Size can be distorted, but they are fairly accurate with distance and direction, particularly when passing through the North or South Pole.

Global Positioning System (GPS)

This global navigation system provides location and time information.

Types of Map Projections: Fuller-Dymaxion Projection

This map attempts to display the entire world at once with minimal distortion.

Types of Map Projections: Van Der Grinten Projection

This map attempts to flatten a globe but display it in a circle. Areas around the equator in this map look smaller than they really are, and the polar regions are extremely distorted.

Types of Map Projections: Gall-Peters Projection

This map has inaccurate shapes in many areas. Area is inaccurate. This type of map is used primarily by governments to study geopolitical relationships.

Types of Map Projections: Mollweide Projection

This map shows equal area proportions, but in doing so it distorts angular conformity. Notice: The northern and western hemispheres are parallel to one another, when in reality they are angled away from each other.

Types of Map Projections: Goode's (Broken) Projection

This map shows true sizes and shapes but distance is distorted.

Types of Map Projections: Mercator Projection

This map uses a cylinder to warp around the globe. The shape of boundaries are accurate, but the size of places and their distances are distorted. For example: Greenland is bigger than South America. A Mercator projection is useful for true directions (navigating or sea travel).

Three ways geographers identify location

Toponym: a place name as determined by a person's name (Pennsylvania), the origins of settlers (New Amsterdam), or physical environment (Tahoe) Site: physical characteristics of a place such as: climate, water sources, topography, soil, vegetation, latitude, and elevation Situation: the location of a place relative to other places (someone from Lynwood, CA will say they are from Los Angeles).

Map Projections and Distortion

Types of Distortion: 1. Distance -places can be farther apart or closer together 2. Direction -places can be oriented incorrectly 3. Space -places may appear more elongated than normal 4. Scale -areas are altered and some objects may appear bigger or smaller Note: Some distortions/inaccuracies are evident in ALL map projections.