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PMS 437

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.

ScaleRep. fractionMap (in/mi)Map (in/ch)Feet per map inch
1:253,440253.440.250.003121120
1:126,720126.720.500.006310560
1:63,36063.3610.01255280
1:62,50062.501.010.01275188
1:31,68031.6820.0252640
1:24,000242.640.0332000
1:21,12021.1230.03751760
1:15,84015.8440.051320
1:7,9207.9280.1660

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 UnitMultiply byEnglish UnitMultiply byMetric Unit
Meters/min3.28084Ft/min0.3048Meters/min
Meters/min2.982582Ch/hr0.33528Meters/min
Meters/min0.03728Miles/hr26.8224Meters/min
Kg/m34.460897Tons/ac0.22417Kg/m3
Kg/m30.062lb/ft316.129Kg/m3
Tonnes/ha0.44609Tons/ac2.2417Tonnes/ha
Kw/m0.28909BTU/ft/sec3.4592Kw/m
Meters0.049709Chains20.117Meters
Meters0.3048Feet3.28084Meters
Millimeters0.0393701Inches25.4Millimeters
kilometers0.62137miles1.6093kilometers
hectares2.4711acres0.40469hectares

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

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Average Latitude for Each State

StateAverage Latitude
Alabama33
Alaska65
Arizona35
Arkansas35
California38
Colorado39
Connecticut41
Delaware39
Florida28
Georgia33
Hawaii21
Idaho45
Illinois40
Indiana40
Iowa42
Kansas39
Kentucky37
Louisiana31
Maine45
Maryland39
Massachusetts42
Michigan43
Minnesota46
Mississippi32
Missouri39
Montana47
Nebraska41
Nevada39
New Hampshire44
New Jersey40
New Mexico34
New York43
North Carolina35
North Dakota47
Ohio40
Oklahoma35
Oregon44
Pennsylvania41
Rhode Island41
South Carolina34
South Dakota44
Tennessee36
Texas32
Utah39
Vermont44
Virginia37
Washington47
West Virginia38
Wisconsin44
Wyoming43

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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)

Recent map of magnetic declination for field navigation.

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NWCG Latest Announcements

NEW! S-231, Engine Boss Course Available Now

Date:  March 6, 2026
Questions? 
Please contact: Incident Operations Subcommittee

NWCG is pleased to announce the new S-231, Engine Boss (Single Resource) course is now available on the Wildland Fire Learning Portal (WFLP). Developed through the Incident Performance and Training Modernization (IPTM) effort, this training supports individuals working towards Engine Boss, Single Resource (ENGB) incident qualifications. 

This is a performance-based instructor-led training (ILT) that focuses on the application of ENGB responsibilities during wildland fire operations, emphasizing readiness, information gathering, risk management, engine tactics, and Wildland Urban Interface (WUI) operations. Trainees apply these skills through scenario-based group work and an optional field day that reinforces hands-on engine operation tasks. 

References:

S-231, Engine Boss (Single Resource) (Instructor-led)

NWCG Engine Boss, Single Resource (ENGB) Position Page

Wildland Fire Learning Portal

NWCG Celebrates 50 Years!

Date:  March 6, 2026
Questions? 
Please contact: NWCG Executive Secretary

NWCG is proud to celebrate 50 years of service to the wildland fire community. Beginning in 1976 with an interagency agreement between the Department of Interior and Department of Agriculture, NWCG has grown to include additional member agencies and is recognized as the standard-setting leader in wildland fire operations.

To honor where we’ve been and highlight where we are going, the NWCG team has created a video showcasing our history and accomplishments. The video is now available on the NWCG website.

References:

NWCG 50 Year Anniversary Video

NEW! S-131, Firefighter Type 1 Course Available Now

Date:  March 6, 2026
Questions? 
Please contact: Incident Operations Subcommittee

NWCG is pleased to announce the new S-131, Firefighter Type 1 course is now available on the Wildland Fire Learning Portal (WFLP). Developed through the Incident Performance and Training Modernization (IPTM) effort, this course is a performance-based instructor-led training (ILT) that focuses on the application of situational awareness and decision making, building on the knowledge and concepts introduced in previous required courses. Using a threaded fictitious fire, each unit focuses on a performance-based activity in which students practice applying their decision-making and problem-solving skills.

The S-131, Firefighter Type 1 course is required for individuals seeking qualifications to be a Firefighter Type 1 (Squad Boss) (FFT1) or an Incident Commander Type 5 (ICT5).

References:

S-131, Firefighter Type 1 (Instructor-led)

NWCG Firefighter Type 1 (Squad Boss) Position Page

NWCG Incident Commander Type 5 Position Page

Wildland Fire Learning Portal

2026 Professional Reading List

Date: March 4, 2026
Questions? 
Please contact: WFLDP Curriculum Management

The Wildland Fire Leadership Development Program (WFLDP) is announcing the 2026 Professional Reading List.  The goal of the annual reading list is to promote the reading and discussion of the selected books throughout the year. 

The six books chosen for this year are: How to Win Friends and Influence People by Dale Carnegie; Leadership Strategy and Tactics by Jocko Willink; Meditations by Marcus Aurelious; Quiet by Susan Cain; The Little Book of Stoic Quotes by Phil Van Treuren; and The Confident Mind by Nate Zinsser.

References:

Professional Reading Program

Wildland Fire Leadership Development Program