Coordinate transformation using Netcad DNS files: Helmert, Affine and TIN methods.
This plugin reads Netcad .dns transformation files and applies coordinate
transformation to selected vector layers.
SUPPORTED METHODS:
- Helmert (4 parameters): Isotropic scale + rotation + translation.
Most common method. Minimum 2 control points required.
- Affine (6 parameters): Different scale in E/N direction + shear.
More flexible. Minimum 3 control points required.
- TIN (Delaunay Triangulation): Local transformation per triangle.
Residual = 0 at all control points (exact pass-through).
Best accuracy for large areas. Minimum 3 control points required.
SUPPORTED DNS FILE TYPES:
- Point-Based ($AMAT + $NOK): Parameters computed from control points via LSQ.
- Matrix-Based ($AMAT only): Parameters read directly from $AMAT matrix.
QUALITY CONTROL:
- Data Snooping (Baarda Test): Iteratively detects suspicious control points.
- Normalized residuals (w-values) vs critical value comparison.
- Error ellipses: sigma_E, sigma_N, sigma_P, semi-major/minor axes.
- Residual vector and error ellipse layers can be added to the map.
MULTI-LAYER SUPPORT:
- Multiple layers can be selected (Ctrl/Shift) and transformed in one step.
- Option to transform in-place or create new layers with custom suffix.
REPORTING:
- HTML report: Opens in browser with full CSS styling.
- PDF report: Generated via QGIS WebEngine.
Compatible with QGIS 3.16+ and QGIS 4.x (Qt5/Qt6).
scipy package required for TIN method.
Plugin Tags