cdm/src/main/java/ucar/unidata/geoloc/projection/proj4/LambertConformalConicEllipse.java
public boolean crossSeam(ProjectionPoint pt1, ProjectionPoint pt2) {
    if (ProjectionPointImpl.isInfinite(pt1) || ProjectionPointImpl.isInfinite(pt2)) {
      return true;
    }

    return false;

    /* opposite signed X values, larger then 5000 km  LOOK ????
    return (pt1.getX() * pt2.getX() < 0)
            && (Math.abs(pt1.getX() - pt2.getX()) > 5000.0); */
  }
public boolean crossSeam(ProjectionPoint pt1, ProjectionPoint pt2) {
    if (ProjectionPointImpl.isInfinite(pt1) || ProjectionPointImpl.isInfinite(pt2)) {
      return true;
    }

    return false;

    /* opposite signed X values, larger then 5000 km  LOOK ????
    return (pt1.getX() * pt2.getX() < 0)
            && (Math.abs(pt1.getX() - pt2.getX()) > 5000.0); */
  }
This returns true when the line between pt1 and pt2 crosses the seam.
When the cone is flattened, the "seam" is lon0 +- 180.

@param pt1 point 1
@param pt2 point 2
@return true when the line between pt1 and pt2 crosses the seam.