In this section you can transform the coordinates (N, E) of the points from one system to another using 2D transformation.

The transformation methods

The supported transformation methods are:
• conformal 2D Helmert transformation (4 parameters);
• conformal 2D Helmert transformation with rotation origin (6 parameters);
• affine 2D orthogonal transformation (5 parameters);
• affine 2D non-orthogonal transformation (6 parameters).

For information on the manner of selecting the transformation method read the page with Recommendations.

Parameters

Parameters can be typed, loaded from a file or from the EPSG database or copied from another parameters box. The description of the buttons and of the contextual menu of the parameters group box can be found at The contextual menu of the parameters group box.

The file with parameters must contain a number of lines equal with the number of parameters + 1 with the following information:
1. text with the description of the transformation parameters;
2. the rotation origin on the east (Eo) (if applicable);
3. the rotation origin on the north (No) (if applicable);
4. the translation on the north (Tn);
5. the translation on the east (Te);
6. the rotation in sexa seconds;
7. the scale factor on both axes or on the east (Se) in the case of the 3rd and 4th methods in ppm;
8. the scale factor on both axes or on the north (Sn) in the case of the 3rd and 4th methods in ppm;
9. the non-orthogonal coefficient in the case of method 4.

The reversal of parameters can be made ​​only for the methods "conformal 2D Helmert transformation (4 parameters)" and "affine 2D non-orthogonal transformation (6 parameters)". For the other methods you can apply the reverse transformation using forward transformation parameters.

In the Parameters calculation section from the main program you can calculate and save these parameters to a file.

Coordinate tables

In the two tables the coordinates can be typed, loaded from a file or copied from another table. The coordinates from tables can be saved to file or can be exported to Microsoft Word or Microsoft Excel. The description of the buttons and of the contextual menu of the tables can be found at The commands of the coordinate tables.

A point from table is considered valid only if its name (point number) and (N,E) coordinates are introduced. If H elevation is omitted then its value is considered 0.000.

Button Select the number of axes

Select from the list the projection system with 2 or 3 axes, i.e. (N,E) or (N,E,H) coordinates.

Button Transform →

By using this button the points from the left table are transformed according to the selected transformation method and then written in the right table.

Button ← Transform

By using this button the points from the right table are transformed according to the selected transformation method using the reverse transformation and then written in the left table.

The button is active only for transformations that support reverse calculation using forward transformation parameters.

Information about the way in which the transformations are made can be found at Used Formulas.