Measuring the length of a curved line

Question

Is there a software tool that will allow me to measure the length of a curved line? I have a series of lines in an image that I want to measure the length of. I have a tablet so I can trace over the lines in the image in order to identify the distance to be measured. There are plenty of tools that do straight lines but sofar I can't find on that does free form curves.

Answer 1

You can use inkscape: select/draw a path and then:

Extensions > Visualize path > Measure path 

or gimp, through the "measure active path" plugin:

Filters > Measure > Active Path 

Answer 2

I know I've seen "mouse pedometers" in the past that would do what you want.

The only example I can find right now is "kdetoys-mousepedometer", and then only in some RPM archives.