Consider the following: -a road map -a circuit board design -a floor plan -a sewing pattern All of these drawings accurately reflect some physical entity. Usually measurements or coordinates of the physical entity are known and can be expressed in standard units such as meters, miles, inches, mils, etc.

My only reason for writing this post is to point out that it is possible to enter coordinates into an SVG drawing in their native values... regardless of how big or how mall the unit is. e.g. a map can be created where path coordinates are specified in miles. -in this case: 1user_unit=1mile. e.g. a sewing pattern can be created where path coordinates are specified in cm. -in this case: 1user_unit=1cm. If necessary the drawing can be scaled with a transform, a viewBox, or a combination of a transform and a viewBox. As pointed out by others: when using a viewBox the whole 90DPI issue goes away!

Below are a couple of examples of how a sewing pattern can be done with SVG using a "user unit" of 1cm. Don't try sewing the pattern at home! Both drawings are identical when printed (except for color). Both drawings will print on 8.5"x11" (letter size) paper. Line thickness is exactly 0.05cm (half a mm). The drawings both consist of: 2 squares exactly 8cm x 8cm 2 circles with radii of exactly 4cm For variety I used a "<rect>" element for one square and a "<path>" element for the other. (No reason for this other than to show there are different ways of drawing objects). And likewise, I used a "<circle>" element for one circle and a "<path>" element for the other.

Note that the coordinates and line lengths are entered in units of cm and thus should be easy to read.

# drawing #1 # this drawing makes use of a transform and a viewBox. <?xml version="1.0" standalone="no"?> <svg version="1.1" width="8.5in" height="11in" viewBox="0 0 8.5 11" xmlns="http://www.w3.org/2000/svg" xmlns:svg="http://www.w3.org/2000/svg"> <g style="fill:none;stroke:red;stroke-width:.05"> <g transform="scale(.39370079)"> <rect x="2" y="2" width="8" height="8"/> <circle r="4" cx="14" cy="6"/> <path d="m 2,12 h8 v8 h-8 z"/> <path d="m 14,12 a 4,4 0 1 1 0,8 4,4 0 1 1 0,-8 z"/> </g> </g> </svg>

# drawing #2 # this drawing uses a viewBox but no transform to achieve the same effect as drawing #1. # the parameters for the rect, circle, and path elements are identical to those in drawing #1. <?xml version="1.0" standalone="no"?> <svg version="1.1" width="8.5in" height="11in" viewBox="0 0 21.59 27.94" xmlns="http://www.w3.org/2000/svg" xmlns:svg="http://www.w3.org/2000/svg"> <g style="fill:none;stroke:green;stroke-width:.05"> <rect x="2" y="2" width="8" height="8"/> <circle r="4" cx="14" cy="6"/> <path d="m 2,12 h8 v8 h-8 z"/> <path d="m 14,12 a 4,4 0 1 1 0,8 4,4 0 1 1 0,-8 z"/> </g> </svg>

I have have attached copies of drawing #1 and #2 for those of you that are too lazy to copy and paste (that includes me).

There are also two attached bonus drawings that show how the height and viewBox parameters can be adjusted to print the drawing at proper scale on two half size pieces of paper. Admittedly this would be more useful for drawings that don't already fit on 8.5"x11" paper!

All drawings will load into Inkscape... and they can all be converted to PDF. But it can be a little awkward using Inkscape to modify a drawing with a viewBox.

-crjw