Transformations

You transform point coordinates using cogo transformations or local transformations.

Cogo transformations

Use a cogo transformation to transform a single point, or a selection of points, using one or a combination of rotation, scale or translation.

A cogo transformation deletes the original point(s) and stores new grid points of the same name.

To reorient and translate a station setup use the Fix station setup Cogo Adjust function. Fix station setup allows you to update the azimuth to your backsight, or update station coordinates, and retains all observations from the station.

Local transformations

Use a local transformation to transform Grid (local) points to Grid points.

Local transformation support is available only when the Advanced Geodetic option is enabled in the Cogo settings screen of the job properties.

There are often occasions in surveying where existing points to be tied into or staked out have grid coordinates defined in one or more coordinate or reference systems, which are different from the current job's coordinate system. These other coordinate or reference systems may be defined based on old base lines where the coordinates are effectively station and offset values from the base (reference) line. Or they may be referenced to a completely arbitrary reference system. For example, an architect may provide coordinates for a building foundation that needs to be positioned and transferred into a real coordinate system on site.

Unlike a cogo transformation, a local transformation does not change the coordinates of the original points. Instead, points can be created as Grid (local), and a relationship to Grid is defined that provides the transformation to the local coordinate system.

Grid (local) points cannot be displayed in the map if a transformation to grid has not been defined.