Transform coordinates

The Transform coordinates dialog box allows you to:

select a certain input coordinate system,
type a XY-coordinate or a LatLon coordinate, using this input coordinate system,
select another target coordinate system,
then, the entered XY-coordinate or LatLon-coordinate will be shown in the selected target coordinate system.

In this way, you can interactively check whether a certain transformation is correct.

This dialog box appears:

when you choose Points, Transform Coordinates from the Operations, Vector Operations menu in the Main window, or
when you double-click the Transform Coordinates item in the Operation-list, or
when you click a coordinate system in the Catalog with the right mouse button and choose Vector Operations, Transform Coordinates from the context-sensitive menu.

The Transform Coordinates dialog box can only be used when a transformation between the input and target coordinate systems is possible. You can:

transform coordinates from a coordinate system projection with a certain projection, ellipsoid and/or datum to another coordinate system projection with a different projection, ellipsoid and/or datum;
transform coordinates from a coordinate system projection with a certain projection, ellipsoid and/or datum to a coordinate system latlon with a certain ellipsoid and/or datum (and vice versa);
transform coordinates from a coordinate system latlon with a certain ellipsoid and/or datum to another coordinate system latlon with a different ellipsoid and/or datum;
transform coordinates from a coordinate system formula to the 'related coordinate system' of this coordinate system formula (and vice versa);
transform coordinates from a coordinate system tiepoints to the 'related coordinate system' of this coordinate system tiepoints (and vice versa).

Furthermore:

when in a coordinate system an ellipsoid is not specified, then a sphere is assumed, and
when in either of the 2 coordinate systems a datum is not specified, then the same datum is assumed.

For more information on coordinate system types, see ILWIS objects : coordinate systems.

Dialog box options:

Input coordinate system:	Select an input coordinate system. Open the list box and select the desired coordinate system, or drag a coordinate system directly from the Catalog into this box. If a description exists for this coordinate system, this description will appear just below this Input coordinate system list box; otherwise the name and type of the coordinate system will be listed.
Decimal degrees:	In case you selected an input coordinate system of type latlon: Select this check box if you wish to specify input LatLon-coordinates in decimal degrees. Clear this check box if you wish to specify input LatLon-coordinates as Degrees, minutes, seconds, N/S, E/W.
Input coordinate:	In case you selected an input coordinate system of type projection, type formula, or type tiepoints: type the X and Y coordinates of a point of interest. In case you selected an input coordinate system of type latlon: type the Lat and Lon coordinates of a point of interest.
Output coordinate system:	Select a target coordinate system. Open the list box and select the desired coordinate system, or drag a coordinate system directly from the Catalog into this box. If a description exists for this coordinate system, this description will appear just below this Output coordinate system list box; otherwise the name and type of the coordinate system will be listed.
Output coordinate:	The calculated coordinates for the point of interest in the output projection will be displayed. Depending on the type of the selected output coordinate system, coordinates will be shown as XY-coordinates or as LatLon-coordinates.

Tip:

When you wish to compare coordinate transformation results of multiple coordinate systems, you can add several different coordinate systems to a pixel information window. Then:

Open a map with 'the input coordinate system' and move the mouse pointer or click at a position of interest;
when a transformation from the current coordinate system to the other coordinate system(s) is possible, the pixel information window will show the transformation results.

For more information, see Pixel information window : functionality.