[SVG to absolute location]

Thank you Carl ,for your explanation.  Suddenly it all became clear

[moving the end of a line to a new position]

I created the lines in Inkscape.  I have no idea why some lines use 'm' and others 'M'.  But I'll regularize the d attributes.

[moving the end of a line to a new position]

Hi Jack.  That helps enormously!  Thanks!

[moving the end of a line to a new position]

I have an animation with 20 little circles, and 4 larger circles.  The small circles are connected to the large circles by lines. 

At one stage of the animation, I move each of the larger circles to a new position, and move the ends of the connecting lines to follow  the moving circle.

Most of the line-ends move smoothly in conjunction with the moving circles.  However some of line-ends immediately reposition themselves somewhere out in left field and only match up with the moving circle at the ends of it's travel.  I have not yet figured out what is different about those lines.  Any ideas?

See the Pen RwGOJyy by sinobra (@sinobra) on CodePen

[moving text to a new position]

Oh, never mind.  Yeah, I have to supply the offsets to the new position.

[moving text to a new position]

I am somewhat confused as to how I should correctly reposition text.  In the Codepen example I can move a circle by supplying new {cx and cy} attributes. For the text that serves as a label to the circle, I thought that I could merely supply new  {x and y} coordinates for the text and the span elements.  Nope!  Do I have to imitate a path, and provide the offsets in x and y to the new position?

See the Pen JjRVjVV by sinobra (@sinobra) on CodePen

[Is it possible to modify the points along a path?]

Thanks guys! The codepen solution explains everything.

[Is it possible to modify the points along a path?]

Thanks for the tip.  But the documentation says that the AttrPlugin is used for modifying numeric attributes,  the 'd' attribute is a string.

 

[Is it possible to modify the points along a path?]

I have seen lots of examples where entire objects (paths) are moved.  But is it possible to modify some points along a path?  For example if I have a line with a path, 

 

 d:"M 92.0,40.0 171.0,40.0"

 

would it by possible the change the endpoint to something like:

 

 d:"M 92.0,40.0 171.0,90.0"