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posted 06/05/07 by Ove Cervin Regression Analysis
Hi again,
It was a long time ago - sorry   ;-)
I've been doing a lot (in my garden...) but finally I have now went through the new feature "Regression Analysis", or at least a bit of it...

Below I'll try to explain how to use it when designing an Alignment.
It's a lot of pictures below, but as they say, a pitures tells more than...

If you for example have a bunch of measured points, like on a centerline, this is a good way to find the most correct approximation of where the line really is.
Here's a set of Points, ordinary ACAD Points.
14-1.png

The new command is found under the menu "Lines/Curves".
I'll start of by creating the line our of the Points.
14-2.png

Select "From AutoCAD points"
14-2b.png

When selecting - don't say you have missed the Selection method "WP" for Window Polygon, or "CP" for Crossing Polygon.
They have been here for ages...  an excellent way to select the Points. It also gives you an idea of which points that are "in a line" when you draw the Polygon.
14-3.png

When you have done that - hit Enter. Then you'll see a red line presenting the approximation of the Centerline. Also a bunch of black/white crosses presenting which Point that have been used.
14-4.png

In the Panorama window (make sure you have it open) you get all data and also a graph presenting how the line is drawn and how far from each selected Point it is.
14-5.png

Here in the Panorama window you also have the option to mark a specific point (3) where the Line actually have to pass through.
14-6.png

When you select a Point to pass through the grapichs in the drawing presents the new position.
14-7.png

From the Panorama window you can also export the data to an ASCII-file or to Clipboard.
14-8.png

You can also Add or Remove Points from the Analysis.
14-9.png

When you close the Panorama window Vista the Line is drawn as an AutoCAD Line.
14-10.png

Do the same for the rest of the Points.
14-11.png
14-12.png

...and also for the ARC Points...
14-13.png

This gives you an ARC
14-13b.png

Open the command "Create Alignment by Layout".
Use the command "Convert AutoCAD Line and Arc" to create the first Subentities of the Alignment. Use "Reverse subentity direction", if necessary, on some of the Subentities.
14-14.png

Now they are almost in place
14-15.png

Finally - add an Curve - done!
14-16.png

I'm pretty sure you find it useful also when doing design in other kind of projects - not only roads. As you saw there are more ways to do this, not only from Points.

Try it out!   Cheers!  / Ove C

Here are the sample files;
one to start with and one complete

Start:
Download file

Done:
Download file

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