Author Topic: Triangulation (re-visited)  (Read 310569 times)

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ymg

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Re: Triangulation (re-visited)
« Reply #480 on: November 26, 2015, 09:22:21 AM »
Rick,

The Voronoi does not need to be created and is not a requirement.

ymg

rw2691

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Re: Triangulation (re-visited)
« Reply #481 on: November 26, 2015, 02:25:25 PM »
YMG,

Using PROF I snapped to a TIN frame on one side of the net, then snapped to another on the farther side.

It built the profile, but it always starts at 0+20. The elevation for 0+20 is also not the start of the polyline for the selection.

I drew a circle with the radius of 20' with its center at the start of the polyline. I checked the elevation where the circle intersects the TIN and near the polyline... it was the elevation posted for 0+20.

This happens with every profile. It appears that the 0+00 station is not being posted.

Rick
Hippocrates (400BC), "Life is short, craft long, opportunity fleeting, experiment treacherous, judgment difficult."

ymg

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Re: Triangulation (re-visited)
« Reply #482 on: November 26, 2015, 03:30:57 PM »
Rick,

Thanks! for the testing, I did fid this bug also and it is corrected
in Version 0.7.0 (not posted yet).

This version will extract section also.

Will post as soon as sections are completed.

ymg

rw2691

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Re: Triangulation (re-visited)
« Reply #483 on: November 26, 2015, 04:12:48 PM »
YMG,

I did contours at all settings for rounding. I found that there are minimal differences between the settings. In particular there are always the same number of vertices. I wonder if you couldn't increase the vertices per the greater roundings. As is, roundings are less extreme paths, but it is not smoothing the course beyond their deflections. Actually, I would prefer to see more vertices and less distortion from the NONE setting.

Rick
Hippocrates (400BC), "Life is short, craft long, opportunity fleeting, experiment treacherous, judgment difficult."

ymg

  • Guest
Re: Triangulation (re-visited)
« Reply #484 on: November 26, 2015, 07:14:04 PM »
Rick,

This is opening a big can of worms.

The method I use is Christensen's, If you look at the litterature
you will find that many other ways have been tried, but none surpass this.

The biggest hurdles is preventing contour from crossing.

I agree with you that the setting changing the degree of smoothing
does not change much of anything.

See here: http://www.theswamp.org/index.php?topic=9042.msg501947#msg501947

ymg
« Last Edit: November 26, 2015, 07:25:20 PM by ymg »

rw2691

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Re: Triangulation (re-visited)
« Reply #485 on: November 27, 2015, 09:25:23 AM »
YMG,

I see you have had to work through a lot scenario's, and have chosen a best solution. If I need "good looks" for a presentation I can always turn them into quadratics.

Rick
Hippocrates (400BC), "Life is short, craft long, opportunity fleeting, experiment treacherous, judgment difficult."

ymg

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Re: Triangulation (re-visited)
« Reply #486 on: November 27, 2015, 11:22:26 AM »
Rick,

If you spline them, you are bound to get crossing contours.

ymg

rw2691

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Re: Triangulation (re-visited)
« Reply #487 on: November 27, 2015, 01:41:36 PM »
YMG,

I have tried it with PEDIT SPLINE, which makes it a quadratic and not a spline. It hugs the lines and stays near the vertice points. I get nearly the same results smoothing at NONE and MAX. The MAX as quadratic keeps it near your pattern. The NONE as quadratic doesn't look bad. I haven't tested it on lines that are very close to each other. I have noticed that it is something I would have to do by copying the contours before converting them. It makes your functions fail. At least the labeling functions, and expect the PROF will crash as well. They aren't type of objects that you are looking for.

I read that your routines won't work without Express Tools installed. Would it be too much to ask what commands you are using that are Express Tools?

Rick

Hippocrates (400BC), "Life is short, craft long, opportunity fleeting, experiment treacherous, judgment difficult."

rw2691

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Re: Triangulation (re-visited)
« Reply #488 on: November 27, 2015, 03:25:00 PM »
YMG,

Can ask what ** does in the following... 

** (princ (strcat  "Minimum Z value: "

...at about line 3924.

The line will be off because I have been adding my own comments.

Rick
Hippocrates (400BC), "Life is short, craft long, opportunity fleeting, experiment treacherous, judgment difficult."

rw2691

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Re: Triangulation (re-visited)
« Reply #489 on: November 27, 2015, 03:31:21 PM »
YMG,

Never mind... I see that it is a variable. I've never seen anyone use *'s as a name before.

Rick
Hippocrates (400BC), "Life is short, craft long, opportunity fleeting, experiment treacherous, judgment difficult."

ymg

  • Guest
Re: Triangulation (re-visited)
« Reply #490 on: November 28, 2015, 09:50:31 AM »
Rick,

I use it as a temporary variable whose value I don't really need.

Most of the times so that I can wrap everything into a "setq" and
eliminates a "progn".

ymg

rw2691

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Re: Triangulation (re-visited)
« Reply #491 on: November 28, 2015, 04:04:39 PM »
YMG,

You do clever programming. Things that I never imagined. I have been unaware that many of the things are even possible. Kudo's!

Rick
Hippocrates (400BC), "Life is short, craft long, opportunity fleeting, experiment treacherous, judgment difficult."

rw2691

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Re: Triangulation (re-visited)
« Reply #492 on: November 29, 2015, 09:12:05 AM »
YMG,

I would like to revisit quadratics. It is a very conservative model for curvature. Its weakness comes by a lack of data. When applied to your own contours, you have developed a control rib with your MAX resolutions. The lack of data has been reduced.

I haven't created any quadratics that have been unfaithful to those enhanced vertices's. In actual application I would always review your MAX conditions, and probably edit them manually... I would do the same after converting them to quadratics. For myself, it's no different than deleting bogus (exterior) TIN's.

In summary, quadratics do introduce a risk that requires a critical review. Nevertheless, as a practitioner and professional, my client always expects a refined product. For them, that is visual. Smoothness. For me it is a practical accuracy. I think that your MAX contouring, combined with quadratic's, makes that happen.

It's an argument. But also only a suggestion. I think it would be nice to have Quadratic Conversion available as an automated "last step" option to production. The contours could be placed on a new layer (having a different color), and comparisons and manual editing would be easy.

In fact a greater tool for analysis would be to have a Tin-Cntr layer, and also an Avg-Cntr (for the MAX values), and a Qdr-Cntr layer (built from the MAX/AVG) which can all be reviewed to aid any manual editing that you might do to the quadratic later... or opt for using any of the others.

Rick
« Last Edit: November 29, 2015, 12:02:22 PM by rw2691 »
Hippocrates (400BC), "Life is short, craft long, opportunity fleeting, experiment treacherous, judgment difficult."

ymg

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Re: Triangulation (re-visited)
« Reply #493 on: November 29, 2015, 03:00:47 PM »
Rick,

I have nothing against quadratics per se, just warning you about the caveat.

Another consideration  is how accurate will be the final contours.

For now, I am concentrating on finalizing the Cross-Sections extractions.
Might  add an option to annotates the alignment.

Also looking, as per your suggestion, into updating the contours as we flip
triangles.

That should bring me to Christmas.

ymg

« Last Edit: November 30, 2015, 02:13:49 PM by ymg »

rw2691

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Re: Triangulation (re-visited)
« Reply #494 on: November 30, 2015, 08:29:35 AM »
YMG,

Good deal... don't let me overload you, and don't let me get away with being dumb. Happy Holidays to you.

Rick
Hippocrates (400BC), "Life is short, craft long, opportunity fleeting, experiment treacherous, judgment difficult."