#!/usr/bin/env python
# coding: utf-8

# # 3D Spherical Harmonic Plots
# 
# This example demonstrates how to generate a simple 3-dimensional plot of the data in an `SHGrid` class instance. We start by generating a set of spherical harmonic coefficients that is zero, whith the exception of a single harmonic:

# In[1]:


get_ipython().run_line_magic('matplotlib', 'inline')
from __future__ import print_function # only necessary if using Python 2.x
import numpy as np
from pyshtools import SHCoeffs

lmax = 30
coeffs = SHCoeffs.from_zeros(lmax)
coeffs.set_coeffs(values=[1], ls=[10], ms=[0])


# To plot the data, we first expand it on a grid, and then use the method `plot3d()`:

# In[2]:


grid = coeffs.expand()
fig, ax = grid.plot3d(elevation=20, azimuth=30)


# Let's try a somewhat more complicated function. Here we will calculate a random realization of a process whose power spectrum follows a power law with exponent `-2`:

# In[3]:


ldata = 30
degrees = np.arange(ldata+1, dtype=float)
degrees[0] = np.inf

power = degrees**(-2)

coeffs2 = SHCoeffs.from_random(power)
grid2 = coeffs2.expand()
fig, ax = grid2.plot3d(elevation=20, azimuth=30)