# Elevation and Distance Question

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Hello all,

I can't find this information in my manual. Are the elevation changes added to the trip distance. For example, if I climb up a 2000' vertical cliff, and go straight back down. Would my trip distance be 4000', or would the distance be 0?

Thanks for the help

Flap

0. To the best of my knowledge.

Zero, I also believe. But why trust us? Test it. Tie a long line to your GPS lanyard, drop it down from a bridge, bring it back up and check! Shouldn't have more then a few random feet from signal drift.

I have a similar type question that i have been wondering. Lets Assume the triangle below is a profile view of a mountain or hill.

You start at "A"

Is the distance to waypoint on GPS "c" or "b"

I am going to guess it has to be "b" because the GPS waypoint wouldn't have the elevation.

I answered my own question but will still post since i typed this mess up.

Hmmm.

If the waypoint "B" has an elevation saved- then what would the distance be? ("c" or "b")

Dont say "d - all of the above"

Good question. I do know that most Garmin units will show a vertical speed in ft/min although it's not very accurate.

Gps track points do have the elevation, at least on Garmins. I use them all the time while download tracks of my bicycle rides. I can even use a spread sheet to show the elevation graph of my ride from the GPS.

However, since the most I ever ride is a 6 degree climb, using trigometry, I can't tell if it is accounting for elevation in determining distance or not since a 6 degree climb makes a very small difference in total distance versus a flat ride.

Magellan MapSend topo will give the straight distance and the terrain distance. The terrain distance will also be broken into rising and decending elevation changes.

The straight distance is what all GPS's should give as they are programmed to the spherical model WGS84 and do not take elevation into consideration.

An even simpler experiment is to program your current location, and a location exactly 10 miles away at some bearing. Then edit that waypoint and give it an elevation higher than Mt Everest and see if it is farther away, noop, nada, no change right?

Edited by trainlove

You are right in that Garmin's units tell you the 2 dimensional distance only. But, as said above, for any reasonable hill, the difference is very small.

Yes but I live in Montana and there are lots of unreasonable hills! I would like to know how far I am hiking. Is the distance adjusted for the terrain? It just seems that my Garmin 60CSx should be doing this.

Flap

Hello all,

I can't find this information in my manual. Are the elevation changes added to the trip distance. For example, if I climb up a 2000' vertical cliff, and go straight back down. Would my trip distance be 4000', or would the distance be 0?

Thanks for the help

Flap

To my knowledge, the distance would be zero

Yep, 2D...

When you are climbing a steep hill, you'll see..... It seems like forever to get there.

So for an out and back you get a horizontal distance of 5.78 km. A total distance of 6.09 km, with a difference of 0.31 km. So you actually hiked 5.36% longer in the above example.

The distance between two waypoints is a great circle distance without regard to elevation...that's the way it is in aviation anyway.

Hello all,

I can't find this information in my manual. Are the elevation changes added to the trip distance. For example, if I climb up a 2000' vertical cliff, and go straight back down. Would my trip distance be 4000', or would the distance be 0?

Thanks for the help

Flap

I just drew a track from the top of one of the nearby 14,000 ft peaks in NG TOPO software. I started drawing on a flat spot on top and I went down off a steep cliff. Track length was 1140 ft. Terrain distance (including elevation change) was 1536, so it shows both distances.

Edited by Grasscatcher

Hello all,

I can't find this information in my manual. Are the elevation changes added to the trip distance. For example, if I climb up a 2000' vertical cliff, and go straight back down. Would my trip distance be 4000', or would the distance be 0?

Thanks for the help

Flap

I just drew a track from the top of one of the nearby 14,000 ft peaks in NG TOPO software. I started drawing on a flat spot on top and I went down off a steep cliff. Track length was 1140 ft. Terrain distance (including elevation change) was 1536, so it shows both distances.

I think you mean the horizontal distance is 1140ft and the track length is 1536ft. In any case, your test is invalid because you are using map (DEM) data not satellite data.

Track length (as seen from space by the satellite) was 1140 and track length as measured on the ground was 1536 which includes the changes in elevation.

Yes the elevation data came from DEM map data , but that does NOT make the test invalid. In fact it may actually be more valid.

If you were to physically travel the exact path that I hand drew on the map, then downloaded that track data to your PC, and analyzed the data, the results would be as previously stated. The DEM data is probably more accurate than the GPS data due to that data axis (z) in the GPS being the least accurate (between x,y,& z) due to satellite positioning.

Track length (as seen from space by the satellite) was 1140 and track length as measured on the ground was 1536 which includes the changes in elevation.

Yes the elevation data came from DEM map data , but that does NOT make the test invalid. In fact it may actually be more valid.

If you were to physically travel the exact path that I hand drew on the map, then downloaded that track data to your PC, and analyzed the data, the results would be as previously stated. The DEM data is probably more accurate than the GPS data due to that data axis (z) in the GPS being the least accurate (between x,y,& z) due to satellite positioning.

But the question is does the GPSr do it? The answer is no. As the original post suggests jumping up and down will result in a dot on your map and a zero length track (however you want to define "track")

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