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Mapping: Map and Field Measurements

  1. Map Scale & Map Distance
  2. Slope Estimation
  3. Unit Conversions
  4. Average Latitude for Each State
  5. Declination

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 62.50 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

Firefighter Math Map Scale; Firefighter Math Spread/Map Distance

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Slope Estimation

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

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 percent, estimating the elevation change and the horizontal distance and calculating the ratio. BehavePlus, and BEHAVE tools before that, default to slope input in percent.

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 percent.

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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.

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Average Latitude for Each State

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

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Declination

Global Reference

Calculator

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

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

Image
Recent map of magnetic declination for field navigation.

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NWCG Latest Announcements

2024 Wildland Fire Emergency Medical Service Awards

Date: May 22, 2025
Questions?  Please contact:
Emergency Medical Committee

The NWCG Emergency Medical Committee (EMC) is proud to announce the recipients of the 2024 Wildland Fire Emergency Medical Service Awards. Each year, EMC recognizes individuals and groups who have demonstrated exceptional actions or accomplishments that go above and beyond their normal mission or job duties.

Congratulations to all the awardees and nominees. Through leadership and initiative, they have made significant contributions to the safety and well-being of the wildland fire community. These honors are well deserved.

References:

2024 Wildland Fire EMS Awards

NWCG Emergency Medical Committee

NWCG Welcomes the Incident Management Teams Association as an Associate Member

Date: May 21, 2025
Questions?  Please contact:
https://www.nwcg.gov/contact-us

The NWCG Executive Board is honored to announce that the Incident Management Teams Association (IMTA) has joined the National Wildfire Coordinating Group as an associate member.

IMTA is a dedicated group of incident management professionals committed to enhancing the profession by promoting standards and fostering collaboration across federal, state, local, Tribal, and private sector partners throughout all phases of incident management.

“Joining NWCG aligns with our mission to elevate incident management professionals nationwide,” said Dr. Randal Collins, President of IMTA. “This is a proud moment for all of us committed to advancing public safety.”

References:

Incident Management Teams Association

National Wildfire Coordinating Group

Updated NWCG Guide for Wildland Fire Modules, PMS 431

Date: May 14, 2025
Questions?  Please contact:
Fire Use Subcommittee

The updated NWCG Guide for Wildland Fire Modules, PMS 431 serves as a supplemental resource for wildland fire module operations, providing information frequently used in the field.

PMS 431 defines the organizational structure, staffing, and qualifications for Type 1 and Type 2 Wildland Fire Modules, outlining their roles in wildland fire suppression, prescribed fire, and resource management. The NWCG Guide for Wildland Fire Modules, PMS 431, should be used in conjunction with the NWCG Standards for Wildland Fire Module Operations, PMS 430.

References:

NWCG Guide for Wildland Fire Modules, PMS 431

NWCG Standards for Wildland Fire Module Operations, PMS 430

Updated NWCG Standards for Wildland Fire Resource Typing, PMS 200 Now Includes Off-Highway Vehicle Typing Standards

Date: May 13, 2025
Questions?  Please contact:
Mobile Fire Equipment Subcommittee 

The NWCG Standards for Wildland Fire Resource Typing, PMS 200 has been updated to include newly developed Off-Highway Vehicle (OHV) typing standards. These standards organize OHV information into logical categories and outline key safety requirements for occupants.

NWCG Standards for Wildland Fire Resource Typing, PMS 200 establishes minimum typing standards for aircraft, crews, and equipment used in national mobilization to wildland fire incidents. Typing designations are assigned based on measurable capability and performance criteria.

References:

NWCG Standards for Wildland Fire Resource Typing, PMS 200