Plot of the absolute value of the spherical ${\displaystyle P_n^m(\cos \theta )\exp (im\varphi )}$ harmonic of degree n=5, and orders m=5,4,3,2,1,0,-4,-5 When the spherical harmonic order m is zero, the spherical harmonic functions do not depend upon longitude, and are referred to as zonal. When ${\displaystyle n=|m|}$, there are no zero crossings in latitude, and the functions are referred to as sectoral. For the other cases, the functions checker the sphere, and they are referred to as tesseral. Spherical harmonics of negative order have the same appearance, but much smaller amplitude and sign (-1)^m