Elevation data

So you do one ride a week, and what was the total elevation for each of the 2 weeks ? 

50 meters is a lot , if it's 300 hm, but insignificant if it's 2500 hm in my opinion. And you'll get the same kind of difference on other brands of bike computers .

I have just submitted a support case for the same reason. Had the 1040 since August, and recently have discovered the following:

• Elevation recorded for any ride with friends are 10-30% LOWER when compare with their records for the same route
• Compare to the exact same routes that I ride daily before using the edge, these routes all have a10-30% LOWER elevation from the Edge device
• When trying to record the same ride using both my Edge device and my phone, the difference is between 20-50%, with the rides recorded from edge always being LOWER

As a workaround, Strava has a feature that allows you to adjust elevation as per their map data, and the elevation appears to be more realistic after that.

I've had many "support case" over the years and not one has resulted in a solution. I always figure it out myself by trial and error or many times it turns out the feature in question does not function as the owner's manual describes. Garmin sucks

Actually, I am on two rides per week, but the duplicated one is once per week. The difference I`ve got in 600mh was close to 100m. And that's a lot.

If there is a huge change in air pressure it happens. Repeat this experiment several times under different climate condition and then make complain to garmin if the results are same. 

Mine has a “known” altitude (my front door) so the barometric pressure sensor can calibrate it self during the start up. This gets around the variances caused by the weather. 

I do not fully agree because variances may occur during the ride itself.

Change in the weather during a ride can occur and will affect the elevation data... But not very much. A change of 1hPa equels ~ 8 meters . From the YR weather service you can see the pressure, and for my location it changes ~ 3hPa from now until midnight, giving around  24 meters of difference.

JoMiSan-Tokage said:

So the crazy thing is that Garmin shows that this week total elevation is lower than previous week, but it should be 50m more.

So, what is the total elevation for the week?

You have to treat this as an estimate. Not only is elevation gain harder to measure, the variation is much closer to the data values people care about. (You wouldn't really notice or care about a 50m difference in horizontal distance.)

JoMiSan-Tokage said:

So, I am wandering… if there is a way to use just map data to get elevation on Garmin? I tried the elevation correction, but it is even worst. Much lower elevation on both rides and the first one is higher. Crazy.

The "elevation correction" uses map data. (It's provided for devices that don't have barometers, which means Garmin rates barometric data as better.)