6.2. Editing a Projection

Whenever a projection is selected from the list its properties are displayed on the right. These properties can be changed and the changes saved to the selected projection using Update. Only a projection that comes from a file can be updated, so if the current layer's projection is selected, Update will be disabled. Add to List adds the projection to the list of available projections as a new entry, and thus makes it available to future Thuban sessions. Clicking New will create an entirely new, empty projection. The Remove button will permanently remove a projection from the list of available projections.

To apply the selected projection to the map the user can click either Try or OK. Try will not close the dialog box, allowing the user to see how the projeciton changes the map. Revert will undo the last projection applied to the map. OK will commit the changes and close the dialog. The user will be unable to undo the changes. Close simply closes the dialog box. If no selection has been applied with Try the selection will not be applied to the map.