# problem with bisections limiting circumferences

geouser shared this question 12 years ago

Hi,

I've built the attached file for showing the coverage of four anthens. In fact they are circumferences delimited by the bisections of the anthens (a Voronoi diagram).

If you push the "play" button (at the bottom of the file) you'll see there is just a moment when the circumferences are not limited and overlap the wrong area. I don't know how to solve this problem...

I know it's a hard question, and I'll understand if I don't get an answer.... :wink:

Anyway, thank you in advance!

Virginia

https://ggbm.at/544543

1

hello

after a lot of tests i have seen the problem are in c3 and b3

it is possible bad definition, perhaps the order of extreme points is erroneus

saludos

1

Thank you, Mathmagic, you were right.

I don't know why, but when I activated the trace of arcs b3 and c3 and play the animation, they became visible just during a millisecond, when the radius of b3 was a little bigger (maybe a pixel bigger) than the setting I defined for it.

So what I've done is setting the same radius multiplied by 0.99, and this way it doesn't appear (I know, it's a very rough solution, but it works, at least...) :flushed:

Anyway, I haven't figured out why it works like this, maybe it's a problem of resolution of distances in Geogebra.

Thanks again!

https://ggbm.at/544581

1

Hello,

Just I thought you might be interested to know this "GeoGebra-elegant-way" to create both the Voronoi diagram and farthest-point Voronoi diagram. (Just use key - on slider, + in farthest case.)

Regards,

Rafa

https://ggbm.at/544693

1

Thanks for your files, they're amazing!

However, I still have the same question: how could we do it for the circumferences not overlap themselves? I mean, how can we achieve that they "respect" the field of the neighbour point? In my file there's something not working, although mathematically it should work....

I don't understand what's happening :cry:

Thanks,

Virginia

1

Hello, Virginia

I agree with Mathmagic, I think you set something wrong in that construction. See what happens when we set the value a = 3.03 or close values. That should not happen, I think.

Till next time!

Rafa

https://ggbm.at/544767

1

Yes, I solved the problem you mention in the second file I attached, but it still has a problem, some arcs overlap.

I'm beginning to think that maybe it's a problem of the graphic card resolution in my computer (do you remember I didn't see correctly your "pop-art" locus maps?).

I don't know if other people has the same problem with animated sliders...

Thanks again and see you soon (maybe in Salamanca?),

Virginia

https://ggbm.at/544777

1

Yes, almost certainly is some of that. Maybe the lack of fit in the responses of the microprocessor and graphics card are reflected in a mismatch between the trace and the visibility condition. In fact, I can reproduce this error on my computer if I increase the speed of the slider (from 0.9 to 3). Have you tried to reduce this speed in your computer? (I know it decreases quite "the grace" of construction...)

Speaking of pop-art, do you know the new ultrafast technique I designed?

You can see in this video: http://www.youtube.com/watch?v=Uj2K_-0gPxQ

See you in Salamanca!

Rafa

1

Hello, Virginia

I agree with Mathmagic, I think you set something wrong in that construction. See what happens when we set the value a = 3.03 or close values. That should not happen, I think.

Till next time!

Rafa

Yeah, maybe you set something value wrong, I have a test, if you set the value a=3.05, it works well. Of course, the problem may be a bug in Geogebra, if true, we'd make a report to the productor

1

Brian, thanks for your contribution. I guess that the problem is within my 4-years-old computer, rather than a bug, but I don't know exactly how geogebra works, so I can't tell for sure....

Rafa, I'd seen your colour maps before...as always, fantastic!

As a geologist, they have remind me a lot the interference figures you can observe at a microscope when looking a crystal: http://www.angelfire.com/ms...

Have you think about coloring fractals with geogebra? maybe it's not difficult with your technique.

Regards,

Virginia

1

Of course, Virginia. In fact, the first figure made (albeit slowly) by the technique of automatic scanning was the Mandelbrot set.

Regards,

Rafa