There are four interfaces that you must implement to plugin your own coordinate system.

• ICoordinateSystemChooser - Implementing ICoordinateSystemChooser
• ICoordinateSystemChooserService - Implementing ICoordinateSystemChooserService
• ICoordinateSystemTransformation - Implementing ICoordinateSystemTransformation
• ICoordinateSystemTransformationService - Implementing ICoordinateSystemTransformationService

Additionally, there are a few layer.xml entries that you must make to properly register your coordinate system, one for your ICoordinateSystemChooserService and one for your ICoordinateSystemTransformationService. You also need to hide INTViewer's standard coordinate system chooser.

LAYER.XML

<filesystem>

        <folder name="CoordinateSystemChooserService">

                <file name="com.interactive.intviewer.gislib.crs.GisCoordinateSystemChooserService.instance_hidden"/>

                <file name="com.mycompany.gis.MyCoordinateSystemChooserService.instance"/>

        </folder>

        <folder name="CoordinateSystemTransformationService">

                <file name="com.mycompany.gis.MyCoordinateSystemTransformationService.instance"/>

        </folder>

</filesystem>