Depending on various conditions, such as number of observations, over determination, quality of the geodetic network, or desired accuracy you can specify the number of parameters that will be determined for the transformation. Transformation parameters are:
- Translation—Delta Easting, Delta Northing.
- Rotation—Rotation 1, Rotation 2. Use Rotation 1 to rotate both axes at the same value.
- Scaling—Scale Easting, Scale Northing. Use Scale Easting to scale both Easting and Northing using the same value.
Also you can specify that for each session the transformation parameters will be determined independently, or you can select a session that will be used to determine the parameters, and some or all other sessions will use the same values.
To specify the transformation
- Open the Measurement dialog box.
- Select a session.
- Under Session, click
to display the Parameter area. The parameters for planimetry and altimetry are displayed on separate tabs. - For each transformation parameter, select one of the options, as shown in the following table.
|
Transformation tab Parameter area |
Description |
|---|---|
|
No |
Specifies that the transformation parameter will not be determined for the transformation. |
|
New |
Specifies that the parameter will be determined, and will be used for the transformation. |
|
Previous |
Specifies that the value of the previous session will be used for the transformation. For the selected session, the value will not be determined, and the transformation will be calculated using the value of the previous session. The previous session is recognized by the session number. For example, session number 4 is previous to session number 5. |
The default settings specify a Helmert transformation.
- Delta Easting: New.
- Delta Northing: New.
- Rotation 1: New. With Rotation 2 set to No, this parameter will be applied to both axes. Both axes will be rotated at the same value.
- Rotation 2: No.
- Scale Easting: New. With Scale Northing set to No, this parameter will be applied to both Easting and Northing.
- Scale Northing: No.
To specify an affine transformation, set all parameters to New.
For each parameter, the Transformation Planimetry tab and the Transformation Altimetry tab displays the option, value and standard deviation.