United States History Student Edition

Reading Maps An important step in reading a map is to study the map key. It explains the lines and colors used on a map. It also explains any symbols, or signs and pictures, used on a map. The map scale is a measuring line that tells you the distances represented on the map. A symbol called a compass rose tells you the position of the cardinal directions —north, south, east, and west. They help you explain the relative location of any place on Earth. Some maps also have a locator map, a small inset map. This shows where the region on the large map is located. 7 CHECK FOR UNDERSTANDING Describing Why is reading the map key important when looking at a map? Using Charts, Graphs, and Diagrams GUIDING QUESTION What are the uses of charts, graphs, and diagrams? Charts, graphs, and diagrams are tools for showing information. The first step to understanding these visual aids is to read the title. This tells you the subject. Charts show facts and numbers in an organized way. They arrange data in rows and columns. To interpret a chart, look at the labels at the top of each column and on the left side of the chart. The labels explain what the data is measuring. Graphs summarize and present information visually. Bar graphs use thick, wide lines to compare data. They are useful for comparing amounts, such as the population of different cities or countries. Line graphs show changes over a particular period of time. A line graph could be used to show the growth of population of a country over 50 years. cardinal direction one of the four main compass points: north, south, east, or west

Occupations of the Constitution’s Framers

Lawyers

31

Others*

12

8

Merchants

4

Politicians

To analyze a bar graph or line graph, look at the labels along the side and bottom. The vertical line along the left side of the graph is the y -axis. The horizontal line along the bottom is the x -axis. One axis tells what is being measured. The other axis tells what units of measurement are being used. Circle graphs show how the whole of something is divided into parts. Each “slice” shows a part or percentage of the whole circle. The entire circle totals 100 percent. Diagrams are special drawings. They show steps in a process, illustrate parts of an object, or explain how something works. 7 CHECK FOR UNDERSTANDING Identifying What type of graph shows change over time? APPLYING WHAT I LEARNED 1. Informative/Explanatory Writing Choose two of the map projections from this lesson Source: Fifty-Five Fathers: The Story of the Constitutional Conversion A circle graph is used to show parts of a whole. Analyzing Visuals What group made up more than half of the founders? *Judges, Physicians, Planters, Philosopher, Professor, Surveyer

and write a short explanation of why one type of projection is better for showing particular features of Earth than another.

2. Collaborating Work with a partner to create a special-purpose map of your community. Be sure to focus on one aspect of your community to show on the map, such as schools, banks, or grocery stores. Include a title, a key with symbols, and a compass rose.

HT32