SCALE "Ratio of the distance between two points on a map and the earth distance between the same two points"

Map Scale can be expressed in three ways: word statement, arithmetic ratio (representative fraction), or as a graphic symbol Word Scale: "1 inch to 2 miles" One inch is represented for every 2 miles on a map Representative Fraction (RF): 1:100,000 1 unit on the map represents 100,000 units of actual ground measurement *Units must be equal cm=cm, mi=mi when complete to have accurate results Graphic Symbol: Bar Scale Allows a distance measured on a map to be translated directly into the correct earth distance by comparing it to the scale or vice versa

Large and Small Scale Large scale maps are 1:50,000 or larger Ex: City Map (1:1,000) Small scale maps are 1:250,000 or smaller Ex: map of the United States (1:1,000,000) Helpful Reminder "The smaller the number in the denominator, the larger the scale" *Look under Visuals and Diagrams

Before we proceed keep this in mind: Every map is to some extent simplified or generalized because it is impossible to show every detail of the real world it represents. The content must be adjusted to make it useful and recognizable representation of the real world, within the limits of the space available and the scale of the map.

Basic Unit Conversions We will only focus on linear measurement for this lesson 1 inch = 2.54 cm 10 mm = 1 cm 100 cm = 1 m 1000 m = 1 km 100,000 cm = 1 km 3.28 ft = 1 m 1 miles = inches or 5280 ft or m or km

Watch an example of an introductory form of map scaling by clicking on Map Scale Proportion Map Scale Proportion

Let's Practice Scaling... Let's say you are measuring from point A to point B in cm and need to convert to inches. How do you do this? 6 cm = ___ inches 1. Look up the cm to inches ratio 2. Set up your equation 3. Divide 2.54cm by 6cm to find inches

Example feet = ___ inches 1. Look up the unit conversion 2. Set up your equation 3. Multiply 100 ft by 12 inches

Finding scale using representative fractions (RF) (Written to RF) Let's look at an example...RF is 1:108,000 … 4 inches = 36,000 ft 1. Find your unit conversion Get the units the same on both sides 3. rewrite 4 inches = 432,000 inches 4. drop your units 4 in = 432,000 in 5. get 1 on the left side of the equation (in this case divide both sides by 4) 6. RF is 1:108,000

Practice! Written 1 inch equals 100 feet... RF is 1:______? 1. Find your unit conversion 2. Equal Units 3. Rewrite 4. Drop 5. Get 1 on the left 6. RF is 1: 1200in

Now lets convert from a RF to a written scale RF 1:250,000 = 1 inch = _____ feet 1. Plug the units from the left side of the written scale into the RF 1 inch = 250,000 inches 2. Convert to the desired units (in this case, inches to feet) 3. 1 inch = 20,833ft

Practice this example on your own piece of paper. RF is 1:250, inch = ____ miles 1. Unit Conversion = 63,360inches in a mile 2. 1inch = __?__ miles 3. 1in = 250,000inches 4. 1 inch = 3.95 miles when the RF is 1:250,000

CONGRATULATIONS! YOU NOW KNOW HOW TO MEASURE LINEAR DISTANCE BASED ON SCALE