interpolating 1D array into 3D array grid in python

Question

I have a 1D array with 81 numbers that corresponds to 81 temperature every 2.5 meters depth and I need to interpolate it to a 3D array grid that has 100 points in z-dir, 6 points in x-dir, and 599 points in y-dir. My function to create the 1D values are:

zz = np.arange(-200,0.1,2.5)
def grid_function(x, ABath=-0.2, BBath=0.1, CBath=50.,DBath=10.):
    """This function creates a theoretical grid"""

    from numpy import tanh, arange


    ans = ABath * (tanh(BBath * (-x - CBath))) + DBath
    return ans

temp = grid_function(zz)

Below there's a cross section of my grid

I don't know if I am clear with what I am asking but if anyone knows a way I would be really thankful.

Regards,

What do the horizontal axis and vertical axis represent in your graph? — Xukrao

Xukrao Xukrao · Accepted Answer · 2018-11-05T23:41:40

You should be able to construct a 3D array from your existing temp 1D array as follows:

zz = np.arange(-200,0.1,2.5)
def grid_function(x, ABath=-0.2, BBath=0.1, CBath=50.,DBath=10.):
    """This function creates a theoretical grid"""

    from numpy import tanh, arange


    ans = ABath * (tanh(BBath * (-x - CBath))) + DBath
    return ans

temp = grid_function(zz)

# Construct 1D 100-element array with z-coordinates
z_new = np.linspace(zz[0], zz[-1], 100)

# Interpolate 1D temperatures at new set of 100 z-coordinates
temp_1d_new = np.interp(z_new, zz, temp)

# Replicate 1D temperatures into two additional dimensions
temp_3d_new = np.tile(temp_1d_new, (6, 599, 1))

You could also take a more direct approach however and start immediately with a z-coordinates 1D array with the desired 100 elements (i.e. skip the interpolation step). Like so:

def grid_function(x, ABath=-0.2, BBath=0.1, CBath=50.,DBath=10.):
    """This function creates a theoretical grid"""

    from numpy import tanh, arange


    ans = ABath * (tanh(BBath * (-x - CBath))) + DBath
    return ans

# Create 1D arrays with x-coordinates, y-coordinates and z-coordinates
x = np.linspace(0., 100., 6)
y = np.linspace(0., 100., 599)
z = np.linspace(-200., 0., 100)

# Create 3D meshgrids for x-coordinates, y-coordinates and z-coordinates
(xx, yy, zz) = np.meshgrid(x, y, z)

# Calculate temperatures 3D array from z-coordinates 3D array
temp = grid_function(zz)

Side note

It's considered good practice to place import statements always at the top of your code file.

interpolating 1D array into 3D array grid in python

1 Answers

Side note