Can anybody help with this problem. After i have finished a long hike i save the track on my 450T and then later send to basecamp and also Garmin Connect. which one displays the correct elevation gain, for instance when i load the track back into the Garmin it says total elevation gain is nearly 3000ft, but basecamp when i select get info states about 1570ft this is also the same with Garmin correct. which one should i take to be the correct info ?.
I don't know anything about the 450t but it sounds like it is showing you Total Elevation Gain = Ascent + Decent, where BaseCamp shows Ascent and Decent numbers?
It turns out that GPS tracks have a fair amount of noise in the elevation values. Both BaseCamp and Garmin Connect smooth the tracks that are sent by the GPS, creating smaller probably better ascent and descent values.
Ground position depending on signal strength varies from 10 ft to 40 ft with a Oregon or Dakota. The blocking of signal by trees, buildings, etc introduces noise. Noise is what you hear on a radio when no or a weak radio station is heard.
GPSs are much more accurate on ground position than elevation. In fact if you have a topo map, you have an option to set track to map elevation. By converting to the map elevation you will increase the accuracy as much as 5 times.
I am just guess but BC is probable smoothing by an average or similar function. For example most GPS's used for geocaching have a average function. The user stands still for several over the geocache they want to hide and the gps automatic takes an average and the gps jumps 2 or 10 or 15 feet.
Take you gps indoors after it has locked onto the satellite and zoom to maximum. Remain in one position and watch the noise.
As an old engineer, I think it is beneficial to explain those technical terms that we tend to use everyday when answer a question. Good answer PSEABOLT.
As an old engineer, I think it is beneficial to explain those technical terms that we tend to use everyday when answer a question. Good answer PSEABOLT.
I couldn't agree more...but we often are asked exactly what smoothing algorithm we are using.
In fact if you have a topo map, you have an option to set track to map elevation. By converting to the map elevation you will increase the accuracy as much as 5 times.
Can you please tell me how you do it? I am using Basecamp, Garmin Etrex (without altimeter) and the map is Topo france.
I am disappointed that currently : - when I import a track from the Etrex to BaseCamp, BaseCamp calculates the elevation from the <ele> in the gpx file; - when I create a track directly with BaseCamp, it takes the elevation from some source looking like SRTM-3, wildly different from the right contour lines of the map.
So that I wondered why BaseCamp could not use the elevation info from the TOPO map, since it apparently contains good DEM info, that BaseCamp is able to display correctly when I click on the map near a contour line.
So please tell me if I can I take the map elevation info into account : - in my GPS unit - in BaseCamp
Actually, when I can create a route on my Etrex Legend with TOPO France V2 loaded, I can display the profile of this route, which must take into account the DEM of the map.
And a new test now gives accurate elevations when I create a route directly in BaseCamp...
BUT : when I walked along the same route and recorded it with my GPS unit, it recorded different, much less accurate elevations in the GPX file!
So :
- how can I make my Etrex record the elevations from the map and not from its own calculation from satelites?
- or, if I cannot, how can I replace, in BaseCamp, the elevations of the GPX file with the elevations from the TOPO map?
