Power adjusted for altitude

[Mike_Hardy]

Hey Nick - I’ve asked for exactly this thing here Fitness Charts using alternative W, specifically based on W:alt

…for exactly the reasons you mention, except my altitude hit is around ~15%! (2500m to sea level) and it makes my charts pretty difficult to interpret that’s for sure

[david]

That’s a good idea but quite tricky to get done. The power-duration and other related curves (power vs HR) are computed for each activity and stored. So I need to store a whole new set of altitude adjusted curves. I have added this to the todo list.

[Mike_Hardy]

One thing maybe worth noting is that the actions->fix data->altitude offset change is always applied after activity initial processing so the ability to reprocess whatever is precomputed, ideally in a batch would be great. I can theory craft features for others to implement all day long tho of course. Thanks for even considering this

[david]

You can do that from the activity list view unless I have misunderstood?

[Nick_van_Dyke]

Ah, I had hoped it could be applied as a layer between the source activities and the PD curve. But that does sound more involved.

Somewhat related, it’s amazing how performant intervals.icu is with all the data it handles!

Thanks for the consideration David!

[evanc]

I know this probably isn’t the intended use of this feature (also googling and searching the forms I havnt found anything) – but I am going to be at 7k feet/ 2100m the next month or so and wondering if there is a way I can override the altitude from zwift to use something like this so I can compare to my otherrides while I am back at sealevel?

[david]

You should be able to use this feature to adjust the Zwift altitude. Also you can now filter for activities by altitude:

Standardize Power Across Elevation

The altitude adjusted power is calculated on the fly for the chart so can’t use that for this. I have added average altitude, min altitude and max altitude to activity. You can see these on the list view and filter there and on the /power page etc.. I have started a job to compute this for everyone but it will take a very long time. If you want to use this on old activities you need to re-analyse them on the activity list page. [Screenshot 2024-05-31 at 08.20.54] [Screenshot 2024-05-31 at 08.…

[ArHu74]

@david

If you want to see all 3 together click Charts → Paste and copy in this code for the custom chart:

Where/how do I do this?

[WindWarrior]

Fields are available:

• power adjusted for altitude (un-acclimitized, first 1-7 days)
• power adjusted for altitude acclimatized

A couple charts, at the bottom of activity click on Charts

then at the bottom of the pop-up ^^ click on chart search

and you’ll find some pre-made charts.

Here is an HC climb where I removed the line for adjust power acclimatized:

You can make your own with the fields available.

Hope that helps.

[ArHu74]

Thanks, that will do. Odd that these didn’t show up yesterday when I searched for altitude

[Bodypilot]

Okay, digging this one up once again…
I’m trying to add the altitude corrected power values to the activity summary (like “normalized power alt.” and “average power alt”) but these fields seem to missing for the summary?
Am I missing something here? If not, can these fields please be added to the activity summary?

Cheers,

[R2Tom]

You can search for Custom Fields Avg Power Alt and Norm Power Alt and add them to your summary.

[Bodypilot]

Thanks @R2Tom , I’ve added your fields.
For anyone trying to this: go to Settings>Sport Settings and add R2Tom’s custom fields. Then go to the activity and choose Actions > Edit Summary. Edit the panel and add the custom fields you’ve just added under Sport Settings. The final step is re-analyzing the activity for the custom fields to be populated (Actions > Analyse)