SVG In Absolute units

See D3/SVG with Absolute Units article.

If the screen resolution is set correctly The Width of the drawing above should be exactly 2 inches. SVG Width/Height = XX * 2 inches = XX pixels.
The BLUE square should be 1 inch in size.
The RED square should be 0.5 inch in size.
The GREEN circle should be 0.5 inch in diameter.

Enter screeen resolution (or choose from the list):

Screen Resolution: