Track is changing colours when zooming.

ulmus shared this problem 5 years ago
Solved

I can color track according to altitude. But, try to zoom map when you have track coloured like that. I think the track should be coloured in one way, regardless of zoom scale. When I have zoom 10km (I mean the scale at the left bottom of map) my track is like a rainbow, when 5 km it is similar, when 1km then whole track is yellow, when I zoom closer then it gets colours back .

Comments (32)

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Update :

1km scale then whole track is yellow

400m scale then whole track is light green!


Edit: all the time I meant 'changes of altitude' not altitude.

Altitude colouring is fine.

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think it's more a setting problem

about simplification track points in zoomlevel...

because the color is computed from point to point.

zoom -> less/more points -> other color

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gynta wrote:

think it's more a setting problem

dataabout simplification track points in zoomlevel...

i think that rounding of calculations can make such things with colouring when zooming. Data of altitude are given but changes of altitude when zooming Locus has to calculate and that is the problem, Locus uses data jumping every some number of track points... and that's why coloring is different depending on zoom level.

But it is wrong when once i have full rainbow and then all is yellow and then all is green!

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agree it's little bit weird.


May you please share such track, because I'm not aware that any of my recorded tracks has similar behavior. Thanks.


To be true, I have currently no clear idea how to improve it, but it usually comes in time ...

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I think that could be more complex problem. Decreasing number of trackpoints should keep extremes in skipped set.


p.s. track will share asap.

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hmm extremes ... extreme speed, altitude, accuracy? There is a lot of extremes ... currently Locus simplify track by ignoring topology, just keep every Xth point. Not best approach, but fast and till then .. enough :)

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yes, it is good and enough for now:) but if it is implemented, then coloring should mean coloring :)

if normaly the track is paint from red to blue the it should not be painted whole in e.g. yellow (without any other color).

but ok, it is not annoying so much :) altitude and speed is fine.

so... maybe in the future, if you have more free time, for now it is just fine.

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as I discovered during last few years, there will never be a "free time". My head is exploding every day under amount of interesting ideas, so share your track and I'll check it tomorrow.


Maybe there will be a simple solution. if not, I'll be at least aware of this problem. And usually one day, solution comes ...

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Ok, here you have one of my tracks . When zoom is about 500m all is green.

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as i wrote...

problem is

simplification of trackpoints

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as i wrote...

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gynta wrote:

as i wrote...

problem is

simplification of trackpoints

Yes, you wrote. So? I have read.

Your post is bringing so much.

;-)

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simplification track points 0

see attached shots.


sorry for double post

useresponse and smartphone...

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gynta wrote:

simplification track points 0

see attached shots.


sorry for double post

useresponse and smartphone...

Remember, I am saying about 'altitude changes' not 'altitude' or 'speed'

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that IS alt.changes :)

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gynta wrote:

that IS alt.changes :)
If so, then colors in my locus are different. As i can see in yor screenshot, all is ok and i wouldnt be raise an error with it. Your screenshot is similar to my speed coloring, and that's why wrote "remember it is altitude change".

My coloring of altitude changes of track is quite different and has nothing to do with short sections which dissapear if zooming out, i am saying when whole track is changing its color! with far zoom out i can see few colors, in 1km zoom *whole* track has yellow color and in 500m zoom *whole* track is green. It is not similar to your screenshot when short section of track dissapear because of zooming.

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As I wrote in anstwer No2

In the conig.cfg are some settings what Locus allow to simplify track (points).

-> show less points on screen in low zoomlevel.


Try attached cfg and see the different presentation in Locus

(backup your orig. cfg)


@Menion i hate this UseResponse $#... B)

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I wanted to work on this issue, but am I blind or is attached track missing here?


@gynta: sorry, but you know. I was 4 years searching for best, use-friendly help-desk. And this is best what I may get. Still hope that new version will be better. Currently they have only 4 months delay :)

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I don't know why but zip disappeared. Here you have once more.

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Oki thanks.


I`m worried, I have no simple solution here.


Problem is, that your track is quite long compare to altitude changes. it`s almost 20 km long and difference between max and min elevation is only 50 m!!


Because as gynta wrote, track is simplified in some zoom levels and because coloring display values only between visible points, result is what you see.


EDIT: during last hour, I changed way how these values are computed. Now it`s sum of all points between two visible points. Never mind. Result is little bit better, but not best. And not best, because of altitude values on your track. Mainly on a

point 1464 is really high value that move min/max values a lot. And so on ...


So result > improved style in Locus. And it can`t be better in your case, because your track is too flat.

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I cannot agree completely with you. Look at my screenshots. First is whole track and it is from blue to red. Second and third is nearly the same zoom but have totally different colors.

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Maybe try to keep two values of extremes of whole track (min and max) and color points within that min max, no matter what zoom you have, then if some points skipped , then any of them would have the same color.

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and you do not agree with which part of what I wrote before?


Anyway as I wrote - "Result is little bit better" - so wait for next version please, thanks.

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Menion wrote:

and you do not agree with which part of what I wrote before?


...track is simplified in some zoom levels and because coloring display values only between visible points,...
I dont agree to calculate colors within only visible point.

If you calculate colors inbetween min and max of whole track then coloring would be independed of zooming.

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imagine that you see only every 50th point, so only point 1, 51, 101, ...


which color you want to select for coloring "change of elevation" when between all these points is exactly same change. Because sum of all changes between 1 - 51 is same as sum of all changes between 51 - 101 and so on.


And this is your case of flat track. All simplified segments has really similar change of elevation. That`s all ...

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I understand the problem, I know something about maths :-) if you skip something it doesn't mean that it doesn't exist. You have to weight the point you left to include information you have skipped. I know what problem you faced and it is difficult. When zooming then one point on the plot has to somehow fit set of points that are skipped and it may depends on extreme that was skipped... Yes, it is a little difficult problem...

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Think this option (altitude changes) is generally senseless - especially for flat tracks.

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gynta wrote:

Think this option (altitude changes) is generally senseless - especially for flat tracks.
:) no it is not senseless... it just tells that track is flat or... not, i think that's why it is, innit?

It tells what kind of track it is, hard or not. But wrong is that once whole flat track is yellow and another time the same whole track is green... so... how flat that track is? Whole track is a little uphill, whole track is a little more uphill or maybe downhill? Who knows?


edit:

If track is flat... i dont know what color tell that track has no uphill and downhill.

Whole track in yellow tells that all the time i will ride downhill? Whole track in green tells that i will ride *whole* track less down or what?

I dont know? I dont know, no color has any caption... i dont know if yellow differes from green for example, does it matter or not?

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ulmus, sorry, but I'll soon close this topic as this discussion leads to nowhere.


You wrote http://help.locusmap.eu/responses/track-is-changing-colours-when-zooming#comment-12662 something about min/max values. I wrote you then, how "elevation change" is computed. From my point of view, I don`t see better way. If you do, then write algorithm how to compute "elevation change" when you have "simplified track". DOT!


And yellow or green - colour are from blue (lowest value), over green, yellow, to red (highest value). Green and yellow are quite close, so it's not a big difference between them. Mainly in case of 20 km long track, where difference is 50 m!! End of discussion, sorry.

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Ok, ending this discussion i looked into my library in my firmwares for meters i am programming and want to share with you only some titles, if you want, just look into that sometime in the future:

mode median bucket, largest triangle dynamic and many others method for downsampling data for visual represanting.

I think that sum you did may be good enough, but not what i have now.

In my projects I am using some kalman filters and median downsampling for lcd representing measured data in meters i am programming for power engineering.

EOT

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Yeah! Now i can say that coloring is working almost perfect.


Hmmm... Had yet there was something wrong? :)

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Perfect, glad to hear it. I had some numerical issues in my own algorithm and fortunately more people complained about coloring, so I had a good reason to check it more precisely.