public static IGeometry ConvertProjToGeo(IGeometry geometry)
{
ISpatialReferenceFactory2 originalSpatialReferenceFactory = new SpatialReferenceEnvironmentClass();
ISpatialReference originalSpatialReference = originalSpatialReferenceFactory.CreateProjectedCoordinateSystem((int)esriSRProjCSType.esriSRProjCS_WGS1984UTM_49N);
ISpatialReferenceFactory2 currentSpatialReferenceFactory = new SpatialReferenceEnvironmentClass();
ISpatialReference currentSpatialReference = currentSpatialReferenceFactory.CreateGeographicCoordinateSystem((int)esriSRGeoCSType.esriSRGeoCS_WGS1984);
return(GeometryUtilities.ConvertCS(geometry, originalSpatialReference, currentSpatialReference));
}