Calibration & Scale

Distance values shown in the app are computed from three settings: Map Scale, DPI, and Drawing Scale. Getting these right is essential for accurate metre measurements.

Setting the map scale

In the Settings section of the sidebar, choose your map's scale from the dropdown. Common scales are provided (1:4 000, 1:5 000, 1:7 500, 1:10 000, 1:15 000). If you select a scale that matches your map, distances will be correct once the DPI is also correct.

Setting DPI manually

If you know the DPI of your map image (for example, if you exported it at a specific resolution), type the value directly into the DPI field in Settings. A typical scanned or exported orienteering map might be 150–300 DPI.

Calibrating DPI from the map

If you do not know the DPI, use the built-in calibration tool:

  1. Enter Calibrate mode using the mode selector in the sidebar.
  2. Find two points on the map whose real-world distance you know — for example, a scale bar, or the straight-line distance between two controls from your results.
  3. Click the first point on the map, then click the second point.
  4. A dialog appears asking for the known distance in metres. Enter the value and click Confirm.

The app calculates and sets the DPI automatically. Switch back to Controls or Variants mode when done.

Tip: For best accuracy, choose two points that are as far apart as possible on the map to reduce the effect of small pixel-placement errors.

Drawing Scale

Drawing Scale is a visual zoom multiplier that affects how thick lines and how large control circles appear on screen. It does not affect distance calculations — it is purely cosmetic. Increase it if you're working with a very large map image and the controls look too small.