The existing coordinate systems in the list are the ones that already have an alias. All coordinate systems in the list that do not have an alias are coordinate systems that do not exist in the datasource.

Double-clicking in the Coordinate System Alias column for a coordinate system that does not already have an alias allows users to type in an alias for this coordinate system. This alias will be stored in the ProjectWise datasource when the coordinate system is created. When no alias is specified, the coordinate system name is used as the alias.

Changing the selection in the Matching Coordinate System(s) list also changes the selection in the Scan Action list and the Replacement Coordinate Systems list.

When the selected coordinate system exists in the datasource, the Scan Action and Replacement Coordinate Systems lists are automatically adjusted so that they reflect the selected coordinate system's settings. You can then click OK to close this dialog if you want to use the selected coordinate system.

If the selected coordinate system does not exist in the datasource, you also have to specify which scan action to associate to this coordinate system (and possible also specify a replacing coordinate system) before you can close the dialog.

• Always Use — When set, the Spatial Location Scan tool always considers this coordinate system as being valid and creates a spatial location for the scanned document using this coordinate system.
• Replace — When set, a replacement coordinate system is associated to the current coordinate system and is used in place of the current coordinate system. This means that when the Spatial Location Scan tool comes across a coordinate system whose scan action is replace, it will create a spatial location for the scanned document using the replacement coordinate system in place of the one that was extracted from the document.
• Use in Current Session — When set, the Spatial Location Scan tool will open up the Specify Coordinate System Settings if it is the first time the tool comes across this coordinate system during the current scan session. Every subsequent time the tool comes across the same coordinate system within the current scan session, it will use it directly without opening up the Specify Coordinate System Settings dialog. When this dialog opens up, users can still overwrite the scan action for this coordinate system and set it to Always Use or Replace. Doing so will ensure that in subsequent scan sessions this dialog does not open up when coming across this coordinate system. If they choose to leave it to Use in Current Session, it will only prevent the Specify Coordinate System Settings dialog to open up in the current scan session.