Calibration maps positions in the image to real graph coordinates. Complete it before tracing.

Reference points

  • Select clear tick marks or grid intersections.
  • Enter the coordinate values printed on the graph, not pixel positions.
  • Spread reference points across the plotting area where practical.
  • Verify calibration against other known ticks before tracing.

Linear and logarithmic axes

A linear axis spaces equal coordinate increments evenly. A logarithmic axis spaces equal ratios evenly; on a base-10 axis, powers of ten occupy equal visual intervals. Values on a logarithmic axis must be positive.

If the result looks offset or distorted, recheck reference point positions, entered values, and axis scale.