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Ellipses' properties and areas of polygons and circles

Posted: Tue Mar 02, 2010 4:48 pm
by andre anckaert
Here is a link to an image showing an ellips and its properties:

http://fotoalbum.seniorennet.be/seniora ... to=1305678

The values of the "Major Point" (which one is that?) are confusing me. The X-value is, as far as I can see, simply the |distance| between the centre point and the endpoint of the smaller radius. I cannot figure out what Y=-37.27 stands for or means. I hope somebody will care to explain that to me, please?

I see this in relation to calculating the area of circles, ellipses and polygons. I found how to find the latter in the Help. But for circles, ellipses, and mixtures of (parts of) these I am afraid we shall have to do some own arithmics??

I dream of finding some means of selecting any contour and see Qcad tell me the area of it. Would that be an illusion?

Posted: Wed Mar 03, 2010 3:02 pm
by andrew
The "major point" is the coordinate of the end point of the major (usually the longer) axis of the ellipse. The coordinate is relative to the ellipse center.

QCAD currently only offers an area tool for polygons. More tools might be added with newer versions.