cdm/src/main/java/ucar/unidata/geoloc/projection/Sinusoidal.java
@Override
    public boolean crossSeam(ProjectionPoint pt1, ProjectionPoint pt2) {
        // either point is infinite
        if (ProjectionPointImpl.isInfinite(pt1) || ProjectionPointImpl.isInfinite(pt2)) {
            return true;
        }

        // opposite signed long lines
        double x1 = pt1.getX() - falseEasting;
        double x2 = pt2.getX() - falseEasting;
        return (x1 * x2 < 0) && (Math.abs(x1 - x2) > earthRadius);
    }
@Override
    public boolean crossSeam(ProjectionPoint pt1, ProjectionPoint pt2) {
        // either point is infinite
        if (ProjectionPointImpl.isInfinite(pt1) || ProjectionPointImpl.isInfinite(pt2)) {
            return true;
        }

        // opposite signed long lines
        double x1 = pt1.getX() - falseEasting;
        double x2 = pt2.getX() - falseEasting;
        return (x1 * x2 < 0) && (Math.abs(x1 - x2) > earthRadius);
    }
Does the line between these two points cross the projection "seam".

@param pt1 the line goes between these two points
@param pt2 the line goes between these two points
@return false if there is no seam