I've just posted a new copy of the "Measure a Picture" sketch, which you can use on any computer, but which is particularly useful on the iPad with its built-in camera. The sketch allows you to measure distances and angles on the included pictures or on pictures that you take with your iPad camera. I've increased the number of rulers and protractors on each page, and made their colors more vivid so that they stand out better on top of the picture.

You can find the new sketch here:
http://sketchexchange.keypress.com/s...sure-a-picture