Posted by André on May 14, 2013; 7:24am
URL: https://forum.librecad.org/Create-points-with-X-abscissa-and-Y-ordinate-on-plumb-line-tp5708045p5708072.html

Hi Claus,

> my english is reeeeally rusted

My english was never really good (I'm german).

> Then you know ABCD coordinates and you need the coordinates of points 1,2,3 and 4 in you picture?

Yes that's correct. Short explaination: In surveying often measure X (abscissa) and Y (ordinate) to coordinate points and therefore are especially (CAD) programs to calculate such points. But I'm in private and want to make a plan from our garden and so it's neccessary to unthink. ;)

In your picture I'm not interested in points P and Q, but these are neccessary as "helping-points". So, my strategy to calculate the coordinates from points who are measured with X (abscissa) and Y (ordinate) - derived from your assistance:
1) create a temporary "helping-point" with "Snap to point with given distance to endpoint" (like P and Q)
2) use the command "modify-rotate" in P and Q to create orthogonal lines
3) create circles with the needed radius
4) create a point with the intersection snap where the circle encounters the orthogonal line

> SECOND PART: I am afraid I cannot help you on the second part: look down here

Ok, sorry - my example was incorrect (I wanted to create an easy and good example and made a mistake). Actually, the line is fixed with coordinates:

The line A-B ist fixed with coordinates and I need the coordinates on plumb line A-B from the points C and D.

Thank you for the comments. It helps me to understand the concepts of LibreCAD.