Image Alignment Checklist
Most measurement errors come from the image, not the protractor. Align the background first, then measure.
Quick checklist
- Pick one clear edge (or axis) to align first.
- Use rotate/flip and the grid until the edge is straight relative to the protractor.
- Adjust brightness/contrast if the edge is hard to see.
- Zoom in when placing the vertex and baseline.
A simple workflow
- Align the image until one edge is straight and stable.
- Place the protractor center exactly on the vertex.
- Use snap or guides to keep a consistent baseline.
- If the angle is over 180°, switch to 360° mode.