private void setSelectedGroup(String value) {
	try {
	    ParameterGroup	p	= null;

	    switch (selection) {
	    case "Elevation" :
		selected_group	= (ParameterGroup) Parameters.getParameterSet("general").getParameterNode(
		    "terrain.elevation");

		break;

	    case "Temperature" :
		selected_group	= (ParameterGroup) Parameters.getParameterSet("general").getParameterNode(
		    "terrain.temperature");

		break;

	    case "Rainfall" :
		selected_group	= (ParameterGroup) Parameters.getParameterSet("general").getParameterNode(
		    "terrain.rainfall");

		break;

	    case "Drainage" :
		selected_group	= (ParameterGroup) Parameters.getParameterSet("general").getParameterNode(
		    "terrain.drainage");

		break;

	    case "Volcanism" :
		selected_group	= (ParameterGroup) Parameters.getParameterSet("general").getParameterNode(
		    "terrain.volcanism");

		break;
	    }
	} catch (Exception ex) {
	    Logger.getLogger(GenerationParametersScreen.class.getName()).log(Level.SEVERE,
			     "Couldnt find the parameter set for {0} {1}", new Object[] { value,
		    ex.toString() });
	}
    }