Sit. Rep. #163: Map Distance vs Hiking Distance

1- Several years ago I was teaching Map & Compass to a group of adults and I stated that map distance was only accurate if the ground was perfectly flat.  And therefore map distance was always less than ground or hiking distance.  The question came from one of the students on “Well how far is it?”  I did not know the answer.  Let me share the method that works on how to answer that question and give you a good estimate of hiking distance.

First:  Measure the map distance with your string as covered in Sit. Rep. #104.  The details matter a lot!  Reminder to mark your strings in the measure that is used for the elevation changes or contour intervals.  One string for FEET/MILES of measure and one string for METERS/KILOMETERS.  (There is a cheat sheet in the table below.)

Second:  The map or horizontal measure and the vertical measure MUST, MUST, MUST (hint) be measured in the same units of measure.  The chart below is done using percentages and works for all units of measure.  (Change mileage to feet, kilometers to meters.)

Examples:
A string measure of 3,500 feet and an elevation change of 30 feet.   (feet vs feet) GOOD.
A string measure of 3,000 meters and an elevation change of 50 feet.  (meters vs feet) BAD.
A string measure of 3 kilometers and an elevation change of 10 meters.  (kilometers vs meters) BAD.
A string measure of 3,000 meters and an elevation change of 60 meters.  (meters vs meters) GOOD.

Third: Every undulation peak and valley must be measured and calculated separately to get a better estimate.  That means more calculating.

Fourth: All distances are positive.

Note: Rounded up
Notes:
Altitude
change
Percentage ChangeMultiply By:
1
kilometer
1,000 Meters
100141.421.42
90134.541.35
0.4 mile2,112 feet
80128.061.2810.3 mile1,584 feet
70122.071.2210.2 mile1,056 feet
60116.621.170.1 mile528 feet
50111.801.120.25 mile1,320 feet
40107.701.080.5 mile2,640 feet
30104.401.0440.75 mile3,960 feet
20101.981.021 mile5,280 feet
10100.501.005

Fifth: Here is a worksheet that you can use to calculate before your trip.

Segment 1Segment 2Segment 3Segment 4Segment 5Subtotal
Map
Distance
Vertical / Altitude
Distance
Estimate
Distance
Segment 6Segment 7Segment 8Segment 9Segment 10Subtotal
Map
Distance
Vertical / Altitude
Distance
Estimate
Distance
Totals

Examples:

10′ rise over 550′ of map distance gives us: 550′ * 1.005 = 552.75′ of hiking distance
30′ vertical drop over 2250′ of map distance gives us: 2250′ * 1.044 = 2,349′ of hiking distance

80 meter rise over 0.8 kilometers gives us: 800 * 1.2806 = 1,024.48 meters of hiking distance

Download the table and worksheet: Hiking Distance change per 100 slope.

I: When you get to the top, what do you think of the view?
J: It is all downhill from here.

K: Did you hear ever hear about Mt. Mitchell.  The tallest mountain in North Carolina?
L: I never could get over it.

M: What kind of coat do you wear while hiking?
N: A trailblazer of course.

O: New Patrol Leader what if a new Scout is annoying you on a camping trip.
P: Can I tell that Scout to take a hike?

Semper Paratus,
Gaither

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