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Locus Map - help desk Topic Problem Locus Map (Android)

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Category Locus Map (Android)

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Inserting trackpoints: Timestamps sometimes way off

Ingo Rau shared this problem ago

Solved

While on holiday, I often used the ability to insert trackpoints into a track (for example, when there was no GPS fix for a while, but later I still knew where I went).

As far as I can see, the idea is that intermediate trackpoints get intermediate timestamps:

TP1: 12.23.20

TP2: 12.23.50

-> TP1.5 gets timestamp 12.23.35

Usually that's what happens, but quite often it's way off and the new trackpoint gets timestamps before TP1 or after TP2, which makes the track inconsistent. I don't have a reproducible example right now and perhaps I'm understanding something wrong - but perhaps it's an obvious bug that you can spot right away?

The same problem 0

Replies (7)

Menion ●

I also noticed similar issue with speed values and forget to check it. Thanks for "reminder".

Indeed I found one possible issue in interpolation of new values for trackpoints. So it should be solved in next Locus version.

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Ingo Rau ●

Thx, will check it then (I still have some tracks from the holidays which I wanted to "improve")

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Ingo Rau ●

Hi Menion!

Unfortunately, this is still not fixed. I've attached three files:

The original track
A copy where I moved/inserted some trackpoints at the end (I initially selected the second-but-last point). As you can see (already in the GPX), the timestamps are wrong, some are after the last point
The screenshot shows some other strange problem: The track is not drawn completely. Is this due to wrong timestamps perhaps? I have to say I never had that before,..

Could you please try to reproduce this?

Files:

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Menion ●

Thank you for your patience Ingo! You are of course right, another small issue that caused this mess found in interpolation mechanism. Fixed! So, next version.

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Ingo Rau ●

3.9.1: Works :) Only tried the above track yet, but that's like it should be. Will test more, but I'm sure it's ok now.

Now if only there was a way to insert points before/after the first/last trackpoint - well, probably will have to make an idea of it... ;)

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Menion ●

Good to hear it.

About inserting points.. just move first or last point to where you need and use smaller red buttons to insert some middle buttons.

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Ingo Rau ●

Yeah, tried that too. However, in this case the timestamp interpolation is a disadvantage: The first/last point keeps its old timestamp and the ones in between get interpolated ones.

Let's assume my GPS got first fix only some 300m after I started. I want to add the beginning of the track, but now my speed in the first 300m is, well, amazing :)

I'd rather have some timestamp-less points in that case that get ignored by statistics/chart, but still have the complete track.

Couldn't you just add "Insert before" / "Insert after" in long-click menu one first/last point? Or do I have to gather votes first ;)

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Menion ●

Understand.

Another buttons, heh ... :). Probably possible, but then it will need a complete new bottom menu with edit options, because there is already too much of them.

Also, this options really isn't so easy to do correctly, so if you really wants this, then it will need a new idea I'm worried.

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Ingo Rau ●

Understand. I was talking about the menu you get when long pressing on a point (green dot) in edit mode - only has two options so far (Edit and Delete), so that wouldn't be overcrowded. But I get that that's not a one-liner ;) Will write it down as idea...

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Ingo Rau ●

Sorry I have to get back to this, but it happened to me again.

I can't really give you the example, it was a long track where I added a lot of points (GPS was picky that day), and when I went through them, they were all fine until a sudden jump back in time. After that timestamps where linear again.

I'm not sure, but I think the jump came after the initial "middle point". I mean, when you start editing, three points are green, and the jump came around the middle one. It may also have been the second (later) initial red point (I inserted points on both sides of the middle point.

Could you please look at your algorithm again?

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Menion ●

Hmm, whole algorithm is quite complex and one tiny issue may cause such troubles. So I see only solution to be able to really precisely simulate this problem.

I'll be careful during editing and when I find something, be sure I'll try to fix it immediately. Same for you please, if you find useful steps that always make this problem. Thanks

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Menion ●

Hello Ingo,

during last four months, I was not able to simulate same problem and I also do not get any report from other people, so I'm marking problem as "solved". If same issue happen again, feel free to continue here. Anyway please be aware, that I really need exact steps to simulate same issue on my device. Thanks for understanding.

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