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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 Week of Remembrance

Date: June 27, 2024
Contact: 6 Minutes for Safety Subcommittee 

As we approach the 2024 Week of Remembrance (WOR), June 30 to July 6, we dedicate this time to thoughtfully reviewing and recognizing the events of the 2018 Mendocino Complex. As such, this year’s theme of “Learning From the Mendocino Complex” embodies a longstanding hallmark of WOR, honoring through learning.

Throughout the week, our energy will be directed toward fostering generative conversations in briefing rooms and at tailgates.

References:

6 Minutes for Safety - 2024 Week of Remembrance

Wildland Fire Lessons Learned Center

Updated NWCG Wildland Fire Risk and Complexity Assessment, PMS 236

Date: June 24, 2024
Contact: Incident and Position Standards Committee 

The June 2024 update of the NWCG Wildland Fire Risk and Complexity Assessment, PMS 236, is now available to meet the current needs for incident management typing.

The NWCG Wildland Fire Risk and Complexity Assessment should be used to evaluate firefighter safety issues, assess risk, and identify the appropriate incident management organization based on incident complexity. Assessing risk, determining incident complexity, and identifying an appropriate incident management organization is a subjective process based on examining a combination of indicators or factors, which can change over time.

References:

NWCG Wildland Fire Risk and Complexity Assessment, PMS 236

Operations Branch Director (OPBD) Next Gen PTB Available

Date: June 10, 2024
Contact: NWCG Feedback 

The NWCG Position Task Book for Operations Branch Director (OPBD), PMS 311-109 is now available for use within the OPBD position qualification pathway. As part of the transition to Complex Incident Management (CIM), the OPBD Next Gen PTB was developed and the position qualification pathway updated.

More information about the Next Gen PTB format can be found on the NWCG Position Task Book webpage.

References:

Operations Branch Director Position Page

Operations Branch Director Next Gen PTB

NWCG Position Task Books

Updated NWCG Standards for Interagency Incident Business Management, PMS 902

Date: June 5, 2024
Contact: NWCG Incident Business Committee 

The 2024 revision of the NWCG Standards for Interagency Incident Business Management, PMS 902 is now available. The uniform application of interagency incident business management standards is critical to interagency fire operations. PMS 902 assists NWCG agencies in constructively working together to provide effective execution of each agency's incident business management program.

References:

PMS 902