Kayak Lake Mead's Map & Compass
Estimating Distance, Time
The ability to estimate distance, a good watch, and awareness of your pace are the MOST important fundamentals of navigation.
The estimation of distance is all you need most of the time.
1. Linear distance vs. terrain distance:
At left is a map with the UTM grid
superimposed; 1000 meter squares. So, it is
1.4 km from “A” to “B”; that is easy enough to
measure; just use the scale provided with each
map. (Also, the diagonal of a square is 1.4
times the side.)
2. Actual Path: If you walk from “A” to “B” your path across the ground will not look like this,
but instead will look something like this,
as you walk around all the obstructions
you’ll encounter such as shrubs, trees, rocks, etc. How much further? Well, that depends upon the terrain and the vegetation, but usually is at least 15% more, even if the vegetation is only moderately dense.
The principal is this; walking the hypotenuse of a triangle is a longer walk than walking the base.
Which, is about 200 meters, or 14% further; this is the terrain distance.
3. Actual Distance: So, do you do a bunch of lengthy calculations? No. Take any map measured distance, as in the case above, 1.4 km, figure the actual distance is going to be about 30% more, so multiply 1.4 km by a factor of 1.3. You’ll get something just under 2 km. Call it 2 km; that is the distance that you are actually hiking. If the vegetation is particularly dense, but not so dense you have to crawl, maybe use a multiplier of 1.5 instead. You’ll develop your own “fudge” factor with experience.
4. Elevation Gain: Again, looking at the elevation profile from "A" to "B"...
When you get to “B” you will be about 20’ higher than when you were at “A”, but you will have hiked
up about 200 feet worth of hills. This is the total elevation gain, which takes into consideration all
the ups and downs. This does not properly figure into the determination of distance, but you do
have to figure the addition of this extra ”20 story building”, that’s in the middle of your hike,
somewhere. I usually figure total elevation gain into my estimation on how much time this is going to
ESTIMATING TIME to GET THERE:
Time equals distance divided by your pace. Usually this is the estimated distance divided by your anticipated pace. Ask yourself two questions. More or less how for is it? And how fast do I plan on going? Some examples:
1. Mountain Biking on a Road:
At left is a map with 1000 m grid squares. How long
is it going to take to bike over to WP 1?
Distance: Count the number of grid squares the
road travels through. I count 3. Multiply that by a “fudge” factor of 1.5, you get 4.5 km. If you measure it carefully you still get 4.5 km. After you ride it; your odometer will show 4.5 km. 1.5 seems to be a good “fudge” factor for unimproved roads and trails.
Pace: You figure you’ll ride at 10 km/hr (6.25 mph).
Time: 4.5 km divided by 10 km/hr equals a little
under one-half hour. ( 0.45 hr is 4 and ½ tenths of
an hour or 27 min.) A little under 30 min is a good
Additional Map Analysis: For the 1st two-thirds of
your ride you are going generally northwest. The
terrain is draining generally to the northeast. This
means you’ll be crossing a lot of gullies; i.e. a lot of
up and down.
2. Hiking Cross Country:
How long will it take us to get from “C” to “F”?
Distance: Count the 1 km squares (4.25 + 1.5 + 2 = 8, if you round up ). Multiply by a “fudge” factor of 1.25
(here the vegetation is very sparse). 8 x 1.25 = 10 km
Pace: You have been, up to this point in your hike, hammering out 1 km every 10 min.
Time: Then ten more kilometers will take 100 min or 1 hr 40 min.
Note: When I count the squares in cases like this I’m just estimating 4.25; I am not measuring.
3. Hiking Up and Down a Steep Mountain:
How long to get from WP 2 up to WP 4? It
is only about 3 km. But this terrain is so steep; I would throw out the concept of distance divided by pace. I suggest using, on extremely steep
terrain, the 1000’ of gain per hour concept:
The elevation at WP 2 is about 6920’.
The elevation at WP 4 is about 9960’.
The difference is about 3000’.
Therefore, the time up will be about 3 hr.
NOTE: The time down steep terrain is usually two-thirds of the time up. So, the time down should be 2 hr.
Or if you’re strong on hills; use the 1000’ per 30 min concept:
@ 1000’ per 30 min the time up there will be about 1 hr 30 min and time down 60 min.
Or if you are stronger than that …RIGHT ON!
4. Combining Trail Run and Steep Mountain:
That high terrain on the left is Mt. Wilson. How long will it take to get up to WP7? From the START it looks like trail to probably the letters “ee” in the word “Creek” , that is about 2.5 km squares X 1.5 “fudge” factor for trails = about 3.5 km. If you are trail running 8 min miles uphill that’s about 20 min. Now, from WP 1 to the summit it is extremely steep, technical terrain (very serious for the novice climber and semi-serious for anybody). It is about 5000’ el. at WP 1 and 7000’ at the summit. That is a 2000’ elevation gain and at 1000’ per hour that section will take 2 hr. Total time will be about 2 hr 20 min up. How much time to get back? Usually the time down is 2/3’s of the time up so about 1 hr 30 min down. Or 3 hr 50 min round trip…that’s cookin! NOTE: The time down of 2/3’s the time up does NOT apply to down-climbing rock but to hike/running.
But several important considerations are:
If you walk from “A” to “B” the profile of your
walk, in terms of elevation change, will not look
the linear distance. Instead your walk will look something like this...