Define coordinate system

Objects, scans etc. may not have a coordinate system associated with them. When working with various objects, or according to overall requirements of a project, it may be necessary to ensure all objects are oriented and positioned correctly. This function is used to define an initial coordinate system to the selected object. This sets a reference system for coordinate conversions, and is required before a coordinate conversion can be performed. Objects with a coordinate system assigned can be used to flag other objects with the same system.

REFER TO How Do I? > Understanding Coordinate Systems for a background discussion of relevant components and derivations of coordinate systems. This discussion may help in understanding the significance and use of options in the function presented here.

Related commands:

Define coordinate system

  1. Select the required object.

  2. On the Position and Filter ribbon tab navigate to the Coordinates group and select Define.

  3. Specify a coordinate system either by automatically transferring the coordinate system applied to another object, or specifying manually by clicking the specify system button.

To transfer a coordinate system automatically from another object, give focus to the Specify system by picking object field, then either:

  • Middle mouse-click and drag the reference object into the field.
  • Left-click the reference object in the View window.

        Alternatively:

  • If you choose to specify a system manually, the Coordinate system panel will open, ready for selecting appropriate attributes.

Add projection scaling to scan points - This checkbox toggles the option to apply projection scaling and distortion as if transforming from a geocentric coordinate system.  This should only be used for raw laser scan data.

Coordinate system options include:

  • Several options based on industry standard setups.
  • User defined grid option allowing full flexibility in defining projection, plus Datum including full transformation capability (linear, rotational and scale settings).

  • Select the Calibration tab to apply custom offset measurements to horizontal and vertical references.
  • Select the Geoid tab to nominate Geoid setting or import a geoid file (*.asc, *.byn, *.ggf, *.gtx).

  1. When a system has been initialised, press OK or Apply.