Combined Transformations

The Combined Transformations feature allows the user to translate, rotate, adjust elevation and/or scale the selected points in a specified coordinate file.  The user may also specify whether the transformed coordinates replace the values in the current coordinate file or are saved to another coordinate file.

The Combined Transformations menu item brings up the Transform Points dialog box.  This dialog is used to configure the transformations that will be applied.
To begin the process, in the Coordinate Files Used area, choose the coordinate file into which the transformed points are to be stored.  If you wish to store them in the current coordinate file, you can go on to the next step.  However, if you wish to have the transformed points stored to a coordinate file other than current coordinate file, click the Browse... button and use the file dialog to choose the desired destination file.

Next, check the checkboxes for each of the transformations you wish to apply.  Then, for each type of transformation to be applied, fill in each item of data in that area of the dialog.

Translate Points

To translate the points check the Translate checkbox, then fill in the data in the edit boxes in this section of the dialog.
The amount that the selected points are translated in the North and East directions is determined by the difference between the northing and easting of the Reference Point and the coordinates specified in the New Northing and New Easting edit boxes.

Reference Point specifies the point in the current coordinate file that is to be used as the reference point for the translation.  All the selected points are translated in the same manner as the Reference Point.  The reference point will be translated by the difference between its current coordinates and those specified in the New Northing and New Easting edit boxes.  You can fill in the New Northing and New Easting edit boxes directly or you can enter a point ID in the New Point edit box.  Assuming the point ID entered is found in the coordinate file, the coordinates read from the coordinate file will be placed in the New Northing and New Easting edit boxes.  You can edit these coordinates or leave them as they are.

Rotate Points

If the Rotate check box is checked, the selected points will be rotated according to the specifications in the Rotate Points area.  Rotation defaults to rotation by an angle but can be changed by merely clicking on the Bearing or Angle radio button.

Use the Rotate About Point edit box to specify the point in the current coordinate file about which the selected points will be rotated.

Rotating by an angle
To rotate by an angle click the Angle radio button.  Next, type in the appropriate angle in the Rotation Angle edit box or click the Pick Angle button and pick the desired angle on the screen.

Rotating by Bearing
To rotate by bearing, click the Bearing radio button then type in the appropriate values in the Current Bearing and New Bearing edit the boxes or click the Pick Bearing button and pick the desired bearing on the screen.
Note: Bearings must be specified using qdd.mm.sss notation, where q is the quadrant (1 = NE, 2 = SE, 3 = SW, 4 = NW), dd is degrees, mm is minutes and sss is seconds.  Seconds can be specified to 0.1 seconds if desired.

Adjust Elevation

If the Adjust Elevation box is checked, the elevations of the points will be adjusted according to the specifications in the Adjust Elevation area.  The type of elevation adjustment can be specified by clicking on the Translate or Scale radio button.

To Translate elevations

The elevations of the selected points will be translated by the difference between the Reference Point elevation and the value entered in the New Elevation edit box.  When you enter a point ID in the Reference Point edit box and click on another edit box the New Elevation edit box will be filled out with the current elevation of the reference point.

To Scale elevations

The elevations of the selected points will be scaled by the value entered in the Multiplication Factor edit box.

Scale

If the Scale check box is checked the northings and eastings of the selected points will be scaled according to the specifications in the Scale area of the dialog. 

Meters to Feet and Feet to Meters
You can scale the coordinates to convert feet to meters or meters to feet by checking the appropriate check boxes.  Using this form of scaling disables the other items in this section of the dialog box.
Other types of scaling:

The Point to Hold is a point in the current coordinate file that will be used to obtain the reference coordinates for the application of the specified scaling factor to the selected points.

Simple Scale - if you choose simple scaling it will calculate the scaled differences in northing and easting between the Point to Hold and each of the points selected for scaling.   This scaled difference is found by calculating the difference between the coordinates of the Point to Hold and those of a given selected point and  multiplying that times the specified Scale Factor.  This scaled difference is then added back to the northing (easting) of the given selected point.

Adjust to Grid - this scaling method uses the Site Elevation (MSL) and the Projection Table Factor to adjust the northings and eastings of the selected points to grid coordinates

Methods of Specifying Point IDs for the Various Transformations

When specifying a point ID in the transformation data (for example to specify the Reference Point when the Translate checkbox is checked), you many select points using any one of the three options listed below:

1. Type the point ID directly into the edit box provided.
2. Point List:  click the Point List button to bring up the Choose Point Blocks dialog.  The left pane shows a listing of all the points found in the current coordinate file.  Highlight the desired point in the Points Available list then click the Add > button and the point selected will be displayed in the Points Chosen list.  In every case you are only allowed to choose a single point.  Once you are satisfied with the point chosen click the OK button.
3. Screen Pick: when you click the Screen Pick button the Transform Points dialog disappears and Choose a point: prompt is displayed at the command line.  You may type a point ID or pick a point symbol from the drawing.

Selecting Which Points Will be Transformed

At any time prior to clicking the OK button you may choose the points to be transformed.  To do this click the Select Points button.  The Transform Points dialog will disappear and you will be prompted to choose the points:

Choose initial points for base selection set from coord file. (Enter when done)
[All/Block/Code/Desc/Elev/Pt-group/Limits/Radius/Select]: - use any of the available methods to specify the points to be transformed.  When done specifying the points press Enter until the Transform Points dialog reappears.

Transforming the points

To transform the selected points, click the OK button.  The points will be transformed and saved to the specified coordinate file.

Prompts

Fill out the Transform Points as described above.

When the Select Points button is clicked the following prompt appears:

Choose initial points for base selection set from coord file. (Enter when done)
[All/Block/Code/Desc/Elev/Pt-group/Limits/Radius/Select]: - use any of the available methods to specify the points to be transformed.  When done specifying the points press Enter until the Transform Points dialog reappears.

Pulldown Menu Location: CG-Survey > Management > Transformations
Keyboard Command: cg_transformations
Prerequiste:  Coordinate file