Arc Consistently Gets Certain Locations Wrong

I’ve been using Arc since Moves shut down, and an issue I’ve seen it consistently have is that it’ll get certain locations wrong, over and over, no matter how many times I correct it.

A previous apartment I lived in was maybe 1/4 a mile from a bar I visited maybe once a month. The entire time I lived there, Arc would always think when I got home I was at the bar. I’d correct it, but it never learned.

Where I currently live the same thing happens, only with a coffee shop I visited once before COVID killed it (RIP). Similarly, the coffee shop is about 1/4 of a mile away, and after correcting Arc hundreds of times, it still nearly always thinks I’m there when I get home.

It does this locations other than home as well. For example, whenever I’m within about 1/2 a mile of a former apartment, it thinks I’m there, even for locations I frequently visit (like a grocery store).

I mentioned this in a review a year or two back, and the developer responded that these issues are fixable. I emailed him a months ago and didn’t hear anything for months. Then he asked me join this forum and ask here. So here I am. I’d really like to fix this issue as Arc is, for the most part, a solid app and the best replacement I’ve seen for Moves.

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Unfortunately I can’t keep up with the number of emails I get these days. There’s just too much work for one person :persevere:

For fixing this problem, you need to search for the place that it’s mistakenly picking, then go through the visits to that place and fix any that are incorrectly assigned to it. If there’s any previous visits assigned to the wrong place, it’ll think that that’s still good information. So it’s those older visits that need to be fixed, to clear up that previously learnt bad information.

I’ve found the quickest fix, to stop it happening repeatedly, is to find the shortest visits that are assigned to the wrong place, and fixing those. You can find these by going into the “Common duration” view of the wrong place, then tapping on the leftmost graph bar, then tap on the “Visits” row below, to see a list of all visits for that duration (ie the shortest duration).

The reason why fixing those ones first solves the problem the fastest is because Arc assigns a place to visits when the recording engine goes into sleep mode. If you arrive home, then don’t move about at all, so the recording engine goes into sleep mode, your current visit (ie home) will be only ~2 minutes long, and the Machine Learning classifier will try to match it up with other short visits that match that location and arrival time. If there’s no short visits assigned to that annoying wrong place, then it won’t be a viable choice, and won’t get picked.

Let me know if that helps!


Matt - to be honest, this explanation is chilling.
I have the same problem as the op and I went to check the other place’s visits and they’re all legit, I can’t just delete them to appease the ML gods.

If the ML algorithm first tags a visit with the closest short visit place, then it should also update the tag when the final visit time balloons to hours, that’s it. Your reliance on the first tag is clearly screwing things up as I have to DAILY fix a tag. I’d rather have to tag manually everything at this point.

My other place is almost a km away too, that’s even more infuriating.

Also bear in mind that the ux flow for fixing stuff is almost unusable so don’t ask us to go around fix shit because hell naw.
I fixed the place for today. Now how do I find the wrong place again to check for other visits? Go figure. I have no answer to that, there is no place where I can see all the tagged places, all of my recent stuff, my private places or confirmed places.

Hi @Amidee!

I recommend taking a different approach in how you engage with me. I am a solo developer, earning barely enough to pay for rent and food, and with a workload suitable for a team of 2+ engineers and 2+ support staff.

If you want me to care for your concerns above those of others with more pressing issues, then your attitude is not a winning one.

So to be honest, I’m not interested in whether you’re chilled, or infuriated, or whether you think I’m screwing things up. Treat me kindly, and you’ll get all the assistance and consideration I can physically give. Treat me poorly and you’ll get told to fuck off.

Now what you’re getting here is a very personal response, from the person who actually builds the app you’re asking about. That’s something you won’t get from Facebook or Google or Apple, if you can even get any reply at all. How you deal with that is up to you, but if you want positive results, then please keep all of the above in mind.


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An update on this: the latest version, 3.6.0, seems to have greatly improved this for me.

Arc was still consistently thinking I was at the cafe that closed at the beginning of COVID when I was home, and making a number of similar consistent mistakes.

Since 3.6.0, that seems to have stopped! Thank you for fixing it.

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Glad to hear that @paulmrest!

I did find a related bug, to do with match scoring for places based on how recently the last visit was. In a bunch of cases that check wasn’t happening. Good to have it fixed!

I’m still having this problem with a couple of locations.
One is a hamburger place in an area where I go often (near my office, near where I might go out at night). Every stop will be marked as that place, even if I’m hundreds of meters away (and the track correctly shows it). I haven’t been at that particular place in a year or so, I correct the issue every time I see it (which is not all the time, since I do not open Arc more than weekly), and yet all visits in a 1km radius are set to that place.

Another is a theater near another area where I go often. If I go in a nearby shop, pass under it with the metro, etc. they’re all applied to that theater. I haven’t been there since 2020 and I keep correcting it.

Please consider investigating this, as this makes place detection completely unreliable in those two areas (at least)

Hi @Aragost!

On any of the visits to these places, have a look at the map and look for the orange circle. If the orange circle is abnormally large or centred in the wrong location (or likely both), that will mean that there’s some visits that have been incorrectly assigned to the place that are far away, and are causing the place’s calculated centre and radius to be quite wrong.

The way to fix this is to tap into the “Total visits” list from the Place view, and scroll down until you find the visits that show up on the map as being far away. That will help you to quickly identify which visits have been incorrectly assigned. You can then tap through to those visits (either from the map or the list), then tap Edit, and correct the visit to its appropriate place.

That will then result in the hamburger place’s data getting updated, and its centre and radius corrected. Once that’s done, the place classifier will stop incorrectly choosing it.

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