Field, Backcountry, and SAR

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Pacing and Distance - Distance from pace count with terrain correction; reference table per stride length.
Magnetic Declination and Bearing Conversion - Magnetic-to-true and true-to-magnetic with east-is-least / west-is-best memo.
Slope Angle and Avalanche Risk Window - Slope angle, slope %, and 30-45 deg avalanche start-zone flag.
Backcountry Water and Caloric Requirement - Water (L) and kcal per person per day with trip totals.
UTM and Lat-Lon Conversion - Krueger / USGS deterministic forward and inverse formulas (WGS84).
Sunrise, Sunset, and Civil Twilight - NOAA solar-position algorithm: sunrise, sunset, civil / nautical / astronomical twilight, daylight minutes.
Lightning 30-30 Rule Countdown - NWS 30-30 rule: seconds between flash and thunder -> distance in miles and seek-shelter advisory.
Magnetic Declination (WMM2025) - Local magnetic declination, inclination, field intensity, and annual change from latitude, longitude, date.
Search Probability of Detection - Cumulative probability of detection across search passes.
Search Track Spacing and Coverage - Probability of detection from sweep width and track spacing, or the spacing for a target POD.
Sweat Rate and Fluid Replacement - Personal sweat rate and rehydration target from a weigh-in/weigh-out (loss = (pre-post) x 16 + fluid - urine).
Search Effort in Searcher-Hours - What sweeping a segment actually costs: track feet = 43,560 x acres / spacing.
Sweep Width Correction (Weather, Speed, Fatigue) - The effective sweep width the searchers actually have.
Area by Coordinates - Enclosed area, perimeter, and winding of a closed traverse by the shoelace method.
Traverse Closure and Adjustment - Latitude and departure misclosure, relative precision, and compass-rule adjusted coordinates.
Hiking Time (Naismith's Rule) - Backcountry / SAR trip-time estimate by Naismith's rule.
Two-Bearing Resection - Where you are standing, from bearings shot to two known points.
Slope Stake Catch Point on a Cross Slope - Where a design side slope actually meets the ground, once the ground's own cross slope is accounted for.
Grade Rod, Cut, and Fill from One Setup - The cut or fill at a shot, from one grade rod that carries the whole design for the instrument setup.
Map Scale: Distance, Area, and Representative Fraction - Ground distance and ground area from something measured off a map at a stated scale.
Slope and Grade from Contour Lines - The slope of a route read straight off a contour map, reported four ways.
Helicopter Landing Zone Size, Slope, and Approach - Whether a clearing will take a helicopter, from the three checks it has to pass together.
Litter Carry Team Size, Rotation, and Effort - What a litter carry-out actually costs in people and hours.
Differential Leveling (HI Method) and Loop Misclosure - Carries an elevation from a benchmark across a site.
Level-Loop Misclosure Distribution (Compass Rule) - Spreads a level-loop misclosure back across the benchmarks so the loop closes.
Stadia Tacheometry (Distance and Elevation) - The classic instrument method of reading a distance and rise off a rod interval, still used for topo checks.
Azimuth and Quadrant Bearing Conversion - Converts between an azimuth and a quadrant bearing, in either direction.
Normal Tension for a Suspended Steel Tape - The pull that makes taping-corrections unnecessary.
Steel Tape Distance Corrections (Temperature, Slope, Tension, Sag) - The difference between a rough measurement and survey-grade distance.
Distance-Distance (Swing-Tie) Intersection - Locates a point from two MEASURED DISTANCES to two known control points.
COGO Forward Locate (Bearing and Distance) - The single COGO step traverse-closure only ever sums over a loop.
Total-Station Slope-to-Horizontal Reduction - The right-triangle reduction of an EDM/total-station slope distance to horizontal distance and elevation.
State-Plane Grid-to-Ground Distance - The grid-to-ground scale factor: elevation factor EF = R/(R+h) with R = 20,906,000 ft.
COGO Inverse (Two Points to Bearing and Distance) - From two known points, the straight-line distance and the azimuth of the line between them.
Leveling Curvature-and-Refraction Correction - The curvature-and-refraction correction on a long level sight.

Field, Backcountry, and SAR

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