The Geographers Tools

The Geographers Tools

by Spencer Clark

​Terms and Names

globe a three-dimensional representation of the earth

​map two-dimensional graphic representations of selected parts of the earth’s surface

cartographer a mapmaker

​map projection a way of drawing the earth’s surface that reduces the distortion caused by converting three dimensions to two dimensions

​topographic map a representation of natural and man-made features on earth

​Landsat a series of satellites that can photograph the entire earth in 16 days

​Geographic Information Systems (GIS) a system that uses digital map information to create a databank to produce specialized maps

​Maps and Globes

​A geographer’s tools include maps, globes, and data. A map’s purpose is to show locations of places on the earth. Maps also show where places are in relation to other places around them.

​Maps and Globes

​A globe is a three-dimensional representation of the earth. It provides a way to view the earth as it sits in space. Because the earth is round, we can see only one-half of it at a time. Globes are not always practical because they are not easily portable.

​Maps and Globes

​People often prefer to use maps, which are two-dimensional representations of selected parts of the earth’s surface. Maps are portable and can be drawn to any scale needed.

​Maps and Globes

​The disadvantage of a map is that distortion occurs when a three-dimensional image is converted to two dimensions. A cartographer, or mapmaker, solves this problem by using different types of map projections. A map projection is a way of drawing the earth’s surface that reduces distortion.

Multiple Choice

Why do cartographers need to use projections when drawing maps?

• Cartographers need to use projections to correct for the distortion that occurs as the earth’s flat surface is flattened to make a map

• Cartographers need to use projections to correct for the distortion that occurs as the earth’s curved surface is flattened to make a map

• Baseball players need to use projections to correct for the distortion that occurs as the earth’s curved surface is flattened to make a map

​TYPES OF MAPS

​The three types of maps are general reference, thematic, and navigational. A general reference map is sometimes called a topographical map. It shows natural and man-made features on the earth. Thematic maps focus on specific kinds of information, such as climate or population density. Navigational maps are used by sailors and pilots to plot a course to sail or fly.

Multiple Choice

What are thematic maps used for?

• Thematic maps focus on specific kinds of information.

• Thematic maps focus on globes.

• Navigational maps focus on roads.

• Thematic maps do notfocus on specific kinds of information.

​The Science of Mapmaking

​The first step in making a map is to complete a field survey. Surveyors observe, measure, and record what they see in a specific area. Today, the observing, measuring, and recording are done by aerial photography or by satellites. Cartographers then use this information and computers to construct maps.

​The Science of Mapmaking

​The best known satellites that provide geographic data, are Landsat and GOES. Landsat is actually a series of satellites that can photograph the entire earth in 16 days. GOES—Geostationary Operational Environmental Satellites—is a weather satellite. It maintains a constant view of the same area of the earth. GOES gathers images that are useful in forecasting the weather.

Multiple Choice

What kind of information does GOES collect?

• GIS collects images that are used for forecasting the weather.

• GOES collects images that are used for forecasting the traffic.

• GOES collects images that are used for forecasting the weather.

​GIS/GPS

​A familiar tool of geographers is the Geographic Information System (GIS). This system uses digital map information to produce a specialized map. GIS provides specialized information to solve problems. For example, it may help builders find a suitable site to build an airport.

​GIS/GPS

​Another tool of geographers is the Global Positioning System (GPS). The system uses a series of 24 satellites called Navstars. They send the exact latitude, longitude, altitude, and time to a handheld receiver

Multiple Choice

What would you use a GPS for?

• to find a precise location on the earth

• to find a precise location on the moon