cdm/src/main/java/ucar/unidata/geoloc/projection/ProjectionAdapter.java
static public ProjectionImpl factory(Projection proj) {
    if (proj instanceof ProjectionImpl) {
      return (ProjectionImpl) proj;
    }
    return new ProjectionAdapter(proj);
  }
static public ProjectionImpl factory(Projection proj) {
    if (proj instanceof ProjectionImpl) {
      return (ProjectionImpl) proj;
    }
    return new ProjectionAdapter(proj);
  }
Create a ProjectionImpl from the projection

@param proj projection
@return a ProjectionImpl representing the projection