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1 · Points
Measured points (your survey — local or arbitrary coordinates)
Control points (the coordinates to fit onto)
Why Best Fit? When a TPS job cannot be computed on control
directly, adjust it in a local arbitrary frame first — then Best Fit
rotates, shifts (and optionally scales) the whole survey onto your
control in one rigorous least-squares step. Point names do not need
to match.
2 · Match measured → control
| Measured | E | N | H | Paired control point | Use | res 2D (mm) | res H (mm) |
|---|
Evenly gridded control can make two pairings fit equally
well — geometry alone cannot tell them apart. If the auto-match
reports AMBIGUOUS, confirm each pair with the dropdowns; nothing is
ever guessed silently.
3 · Fit settings
Fixed scale keeps your survey's measured size and only
rotates + shifts it — the normal choice. Free scale also stretches it
to the control; use it as a diagnostic (the ppm value tells you about
shrinkage or a scale error), not as a default.
4 · Results
Fit residuals (control − transformed measured)
Transformed coordinates (all measured points)
| Measured | Control | Use | res 2D (mm) | res H (mm) |
|---|
| Name | E | N | H |
|---|
All computation happens in this browser tab — your
coordinates never leave this device.