cdm/src/main/java/ucar/unidata/geoloc/projection/VerticalPerspectiveView.java
@Override
  public ProjectionImpl constructCopy() {
    ProjectionImpl result =  new VerticalPerspectiveView(getOriginLat(), getOriginLon(), R, getHeight(), false_east, false_north);
    result.setDefaultMapArea(defaultMapArea);
    result.setName(name);
    return result;
  }
@Override
  public ProjectionImpl constructCopy() {
    ProjectionImpl result =  new VerticalPerspectiveView(getOriginLat(), getOriginLon(), R, getHeight(), false_east, false_north);
    result.setDefaultMapArea(defaultMapArea);
    result.setName(name);
    return result;
  }
"map limit" circle of this radius from the origin, p 173