As mentioned on Slack, an undo feature would be incredibly difficult to build, and would most likely need to be written for each specific kind of edit action. (Although if I did go ahead with building it, I’d very much hope to come up with a solution that could be generalised to all kinds of edits!)

What that means is that it would be very time consuming to build, so will require a lot of votes before it can be moved from “suggestion” to “planned”. I’m certainly not against the idea! It will just be a very big task, so needs a lot of people wanting it, to justify the time spent on it.

Another important question is how large you would need/want the undo queue to be… Unlimited undo is not feasible IMO, so there would need to be a different approach.

I just confirmed a 2-hour bike ride, not realizing that Arc identified a 1hr 50min stop at the end of said ride as part of the ride. I’ve definitely lost other locations as well (usually short visits, today was an anomaly) due to confirming transit mode before realizing that it was swallowing up a visit. Undo would definitely help me!

It sounds like an option to remove a confirmed activity type might capture these use cases without requiring a complicated generalized undo feature. What do you think?

This feature request is technically near on impossible, no matter what way you look at it. I’m only leaving it under “Suggestions” instead of “Rejected” because technically I’m not rejecting it, I’m saying “it’s not possible to do”.

When you make an edit in Arc, the processing engine is then triggered and does its own work on the timeline data, making any edits of its own that it now thinks are appropriate, based on the now changed data.

So to get the data back to the state it was in before the user edit would mean also rolling back all changes that the processing engine made too. And the processing engine doesn’t work in single passes, it works in iterative loops until no more possible cleanups are found.

So that means that one edit by the user can potentially result in tens or hundreds of edits, all of which would need to be rolled back.

Then add on top of that the fact that the recording engine may also still be awake and doing its thing, adding new data to the timeline, potentially into the timeline item that was edited. The processing engine will then also be responding to that new data.

Adding an undo feature to what’s essentially a live data stream is … well, I won’t say it’s impossible, but it’s near enough to impossible that it’s just not feasible.

My goal is to add the “Segment Splitting” feature instead, which will take care of the overwhelming majority of cases where people want to undo an edit they made, and also undo an edit that the processing engine made. Once that feature is built, the demand for (and need for) specifically an Undo feature should be much less.

Aye, thanks for the response Matt! I think what I am suggesting is that although “undo” would be pretty technically challenging, removing a confirmed type from an event and re-segmenting and re-classifying the samples, even under the new model, might address some of the issue that happen when we accidentally classify a whole segment incorrectly. It’s not an undo, since the original segmentation is lost and the model has probably incorporated new data, but it may functionally allow us to re-label different parts of a activity correctly.

Does that make sense as a separate feature suggestion perhaps?

I’ve been on holidays in Japan for the last two weeks and Arc has been extremely useful. The biggest problem I’ve had though is either Arc adding the wrong things when something is confirmed, or I’ve accidentally hit the wrong activity; wiping out a significant amount of walking (usually).

The funniest was when Arc added the walk from the Shinkansen train to the hotel to the train activity, so now I have the bullet train stopping at the hotel reception instead of the station. Because we had travelled hundreds of kms, the short bit at the end went unnoticed. It also affected the average speed of the train I think?

Maybe you should have an “Are you sure?” option in the settings? Or some way to visualise what is about to change before pressing the button?

Gordon, for what you describe there (I get the same kinds of problems!) the best solution will be the Segment Splitting feature, which I will be adding in hopefully Arc 3.2.

https://changemap.co/bigpaua/arc-app/task/3205-split-a-segment/

Adding Undo to Arc would be such a monumentally difficult (and potentially impossible) task that it’s very unlikely to ever happen. But segment splitting is very possible, and very much going to happen (and hopefully soon). So that’ll be the saviour in these cases.

Basically what it’ll mean is that if either Arc has joined something together that it shouldn’t have, or we’ve got into that situation by an accidental edit action, it will be easy to extract out the correct segments again, by being able to either tapping on the exact starts and ends of a segment while zoomed in on the map, or giving explicit start/end times for a new segment to extract, then saying “this bit here that I’ve chosen, that should be extracted out as walking/train/etc”.

So that’ll give us the power to make very exact edits, for all those cases where either Arc hasn’t been able to identify the transport mode change accurately enough, or we’ve got into that situation by mistake.

I think ultimately that will be much more useful than an Undo feature anyway, given that it will be applicable to many more situations. Undo would only be useful for our own mistakes, but Arc makes mistakes too (especially when you’re in an area that it hasn’t seen you travel in before, so it’s making less educated guesses). Being able to very exactly correct Arc’s mistakes as well as our own will be great!

I’ve moved this one to Rejected now, given that the new Split Segment feature has been a success, and deals well with probably almost all of the cases where an Undo feature would have been warranted.

Split should do the work here, yes. Maybe some refinement since I still struggle with the usage of split. :) …but please priority to dark mode first. :))

The problem with ARC is that confirming activities and locations is by description and not visual. MoveX has a visual confirm which is much more intuitive. I’m thinking what would be more visual in ARC but I can’t think of something that would fit in existing UI.