Calculating elevation gain.

[MadRiver]

Bowing my head slightly in a sheepish manner as I ask a really stupid question. How does one calculate elevation gain? Do you differentiate between total gain and net gain? Do you calculate regains after loss? I have never bothered to think about the elevation gain of a trail, I just know how long it will take me to hike to the summit. I’m just curious how one calculates the gain.

For instance, how would I calculate a Falling Waters to Old Bridal Path trip over the ridge?

 

[vegematic]

Do you calculate regains after loss?

Yes, if I'm climbing it, I include it. The WMG does the same. If you look at a trail description for, say, the Franconia Ridge Trail you will notice that the elevation gain going from Lincoln to Lafayette is greater than just the difference between the summit elevations. It is measured from the col between them.

If you look at the trail description in reverse you will see that it shows an elevation gain going from Lafayette to Lincoln, even though there is a net loss, because you must re-climb some of what you gave up descending Lafayette.

-vegematic

 

[MadRiver]

So I have to piece together the separate components, e.g. loss and gain to arrive at the overall gain similar to piecing together the mileage of a trip by adding each section? Example:

Point A to point B = 1,200 feet elevation gain

Point B to Point C = 800 feet elevation loss

Point C to Point D = 500 feet elevation gain

Point D to Point E = 200 feet elevation loss.

Is the elevation gain 700 feet? If so it doesn’t seem fair given I hiked up 1,200 initially.

 

[bikehikeskifish]

So I have to piece together the separate components, e.g. loss and gain to arrive at the overall gain similar to piecing together the mileage of a trip by adding each section?

The total elevation gained is the some of all the individual elevation gains (but not losses.) If doing a loop where the net gain is always zero then the gain = loss.

700 is the net gain, 1700 is the total gain.

Tim

 

[NH_Mtn_Hiker]

I always use Total Elevation Gain.

Net gain is pretty much meaningless.

 

[Nessmuk]

So.... is there a minimum dip resolution that doesn't count in the total gain calculation? If I descend 500 feet and climb back up 500 that's obvious. What if I descend into a 10 foot (or one foot) depression and climb back up? At what resolution does adding small gain segments become meaningless?

 

[dr_wu002]

So.... is there a minimum dip resolution that doesn't count in the total gain calculation? If I descend 500 feet and climb back up 500 that's obvious. What if I descend into a 10 foot (or one foot) depression and climb back up? At what resolution does adding small gain segments become meaningless?

When it becomes significant to you, I guess? If you're doing a hike with 2500' elevation gain and there are 7 x 10' ups and downs, that's only an additional 70' -- less than 3% of your entire hike (in terms of elevation gain).

-Dr. Wu

 

[vegematic]

As for "minimum dip resolution" I would say the contour interval on the map you're using. Around the Whites that might be 50-100 feet. If you are using a GPS to track your movement as you hike it will have some degree of uncertainty.

Personally I go with whatever I measure (or interpolate) from the contour map. This is usually pretty consistent with elevation gains listed in WMG. I find that on a mountain climb the little bumps (10-20 feet or so) that don't appear on the topo add up to a small fraction of the total climb. The "small bump" error would be comparable to the uncertainty due to interpolating on the map.

Occasionally, as on the Grafton Loop recently, I had what appeared on the map to be a gradual descent with lots of flat mixed in. However there were a lot of minor ups over the course of the 9 miles, so that they comprised a significant portion of the total effort for the day. It's times like those when the WMG says something like "...may take longer than anticipated due to numerous small ups and downs..."

-vegematic

 

[bignslow]

I have an unnecessarily complicated method for looking at total gain for a trip if it is not already in a guide book (this could be taken care of by buying software not using free online tools):

1) Map out route at www.gmap-pedometer.com (you can show the elevation profile map at the bottom)
2) Save route at gmap-pedometer
3) Import gmap-pedometer to www.mapmyride.com (it seems silly since they both do the same thing, but I find it easier to input routes on gmap-pedometer)
4) Export elevation profile to CSV file (because the total gain calculations on map my ride i've found are incorrect)
5) Import csv file into excel and sum all of the positive vertical gains

The easier version of this is to do segments at gmap-pedometer, for this method i'll only do changes of ~100 feet, anything smaller gets ignored.
My first segment will be from the trailhead to the first high point (whether this is a summit or a bump in between). From there I go to the next col and do the segment from the col to the next bump, and so on until I have all of the cols taken care of. On the elevation profile it shows a min and max elevation, so I subtract the two and continue. Most trips I can get an accurate elevation gain figure with no more than 5-6 segments.

 

[Oldsmores]

Bowing my head slightly in a sheepish manner as I ask a really stupid question. How does one calculate elevation gain? ...

However makes you happy , unless you're trying to set an official record of some sort.

 

[RoySwkr]

So.... is there a minimum dip resolution that doesn't count in the total gain calculation? ...At what resolution does adding small gain segments become meaningless?

As V says, it's harder to add climbs less than the contour interval of the map, in "50 Hikes" Dan Doan counted 20' contours for the Mahoosucs and felt it didn't necessarily get them all. Your GPS track log probably lots of the small bumps are jitter rather than true climbs.

One group I know counts only bumps of 80' or more with the thought than gains less than that are not enough to slow you down whereas longer gains may put you into chug mode.

Of course no numerical value can compare the relative difficulty of going up and down over little rocky bumps like the Mahoosucs with walking on a smooth path like an old logging road. Even stepping over fallen trees makes it notably harder, compare times for ordinary races vs hurdles.

 

[DougPaul]

Your GPS track log probably lots of the small bumps are jitter rather than true climbs.

Many GPSes also skip sections if they lose lock.

The underlying problem is the same as the "how long is a trail" problem. Both are fractals and the total climb is not well defined (ie there is no unique answer for either the climb or the length for objects like typical hiking trails).

Doug

 

[Rick]

I count it in the tally if, while I am hiking, I have to tilt my head up and say "Oh #$#$##$@$. Another frigging hill?!?!????"

 

[cushetunk]

Many GPSes also skip sections if they lose lock.

The underlying problem is the same as the "how long is a trail" problem. Both are fractals and the total climb is not well defined (ie there is no unique answer for either the climb or the length for objects like typical hiking trails).

Doug

Since they are both fractals, does that mean that I regularly hike infinite distances while gaining infinite elevation? Sweet... I knew I was hardcore!

 

[DougPaul]

Since they are both fractals, does that mean that I regularly hike infinite distances while gaining infinite elevation? Sweet... I knew I was hardcore!

Only if you take infinitely small steps...

Doug

 

[Nessmuk]

Only if you take infinitely small steps...

Doug

Sometimes on a long hot neverending climb it seems that my steps are infinitely small.

This all reminds me of Zeno's Paradox.