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Map Scale & Map Distance

The map scale is printed in the map legend. It is given as a ratio of inches on the map corresponding to inches, feet, or miles on the ground. For example, a map scale indicating a ratio of 1: 24,000 (in/in), means that for every 1 inch on the map, 24,000 inches have been covered on the ground. Ground distances on maps are usually given in feet or miles.

 Scale Rep. fraction Map (in/mi) Map (in/ch) Feet per map inch 1:253,440 253.44 0.25 0.0031 21120 1:126,720 126.72 0.50 0.0063 10560 1:63,360 63.36 1 0.0125 5280 1:62,500 62.5 1.01 0.0127 5188 1:31,680 31.68 2 0.025 2640 1:24,000 24 2.64 0.033 2000 1:21,120 21.12 3 0.0375 1760 1:15,840 15.84 4 0.05 1320 1:7,920 7.92 8 0.1 660

Slope Estimation

 Slope (Degrees) Slope (Percent) 10º 17.6 % 20º 36.4 % 30º 57.7 % 40º 83.9 % 45º 100 % 50º 119.2 % 60º 173.2 % 70º 274.7 % 80º 567.1 % 90º ∞

Standard LANDFIRE slope themes are represented in units of degrees (°).  Many locally produced landscapes over the year’s stored slopes in percent (%).  It is much easier to estimate slope in %, estimating the elevation change and the horizontal distance and calculating the ratio.  BehavePlus, and BEHAVE tools before that, default to slope input in %.

Firefighter Math Slope Percent and Slope Angle

To convert from slope in degrees (°) to slope in percent (%), a scientific calculator is needed.

1. Enter the slope in degrees
2. Press the Tangent button
3. Multiply the result by 100 to get slope in %

Unit Conversions

Online and downloadable apps are available from Apple (OSX & IOS), Google Play (Android), and MS Windows for making unit conversions for distance, temperature, area, volume, weight, time, energy and other items.

 Metric Unit Multiply by English Unit Multiply by Metric Unit Meters/min 3.28084 Ft/min 0.3048 Meters/min Meters/min 2.982582 Ch/hr 0.33528 Meters/min Meters/min 0.03728 Miles/hr 26.8224 Meters/min Kg/m3 4.460897 Tons/ac 0.22417 Kg/m3 Kg/m3 0.062 lb/ft3 16.129 Kg/m3 Tonnes/ha 0.44609 Tons/ac 2.2417 Tonnes/ha Kw/m 0.28909 BTU/ft/sec 3.4592 Kw/m Meters 0.049709 Chains 20.117 Meters Meters 0.3048 Feet 3.28084 Meters Millimeters 0.0393701 Inches 25.4 Millimeters kilometers 0.62137 miles 1.6093 kilometers hectares 2.4711 acres 0.40469 hectares

Firefighter Math Conversions reference provides several tables and conversion factors for the user.

Average Latitude for Each State

 Alabama 33 Louisiana 31 North Dakota 47 Alaska 65 Maine 45 Ohio 40 Arizona 35 Maryland 39 Oklahoma 35 Arkansas 35 Massachusetts 42 Oregon 44 California 38 Michigan 43 Pennsylvania 41 Colorado 39 Minnesota 46 Rhode Island 41 Connecticut 41 Mississippi 32 South Carolina 34 Delaware 39 Missouri 39 South Dakota 44 Florida 28 Montana 47 Tennessee 36 Georgia 33 Nebraska 41 Texas 32 Hawaii 21 Nevada 39 Utah 39 Idaho 45 New Hampshire 44 Vermont 44 Illinois 40 New Jersey 40 Virginia 37 Indiana 40 New Mexico 34 Washington 47 Iowa 42 New York 43 West Virginia 38 Kansas 39 North Carolina 35 Wisconsin 44 Kentucky 37 Wyoming 43

Declination

Global Reference: https://maps.ngdc.noaa.gov/viewers/historical_declination/

US/UK World Magnetic Model - Epoch 2015.0 Main Field Declination (D)

(East Declination in Red, West in Blue; subtract from true compass reading)