# 2d contour plot in python using 1d x y and z variables

When working with 2D contour plots in Python, it is common to have the data represented by 1D arrays for the x, y, and z variables. In this article, we will explore three different ways to create a 2D contour plot using these variables.

## Option 1: Using numpy.meshgrid

The first option involves using the numpy.meshgrid function to create a grid of coordinates from the 1D arrays. This allows us to evaluate the z values at each point on the grid and plot the contour.

``````import numpy as np
import matplotlib.pyplot as plt

# Define the 1D arrays for x, y, and z
x = np.linspace(0, 1, 100)
y = np.linspace(0, 1, 100)
z = np.sin(2 * np.pi * x) * np.cos(2 * np.pi * y)

# Create a grid of coordinates using meshgrid
X, Y = np.meshgrid(x, y)

# Evaluate the z values at each point on the grid
Z = np.sin(2 * np.pi * X) * np.cos(2 * np.pi * Y)

# Plot the contour
plt.contour(X, Y, Z)
plt.xlabel('x')
plt.ylabel('y')
plt.title('2D Contour Plot')
plt.show()``````

This option is straightforward and allows us to create a 2D contour plot using the numpy and matplotlib libraries. However, it requires creating a grid of coordinates, which may not be necessary for all applications.

## Option 2: Using numpy.reshape

The second option involves reshaping the 1D arrays for x, y, and z into 2D arrays using the numpy.reshape function. This allows us to directly plot the contour without creating a grid of coordinates.

``````import numpy as np
import matplotlib.pyplot as plt

# Define the 1D arrays for x, y, and z
x = np.linspace(0, 1, 100)
y = np.linspace(0, 1, 100)
z = np.sin(2 * np.pi * x) * np.cos(2 * np.pi * y)

# Reshape the 1D arrays into 2D arrays
X = x.reshape((len(x), 1))
Y = y.reshape((1, len(y)))
Z = z.reshape((len(x), len(y)))

# Plot the contour
plt.contour(X, Y, Z)
plt.xlabel('x')
plt.ylabel('y')
plt.title('2D Contour Plot')
plt.show()``````

This option eliminates the need to create a grid of coordinates by directly reshaping the 1D arrays into 2D arrays. It is a more concise solution but may be less intuitive for beginners.

## Option 3: Using numpy.outer

The third option involves using the numpy.outer function to compute the outer product of the x and y arrays. This creates a grid of coordinates without the need for meshgrid or reshape.

``````import numpy as np
import matplotlib.pyplot as plt

# Define the 1D arrays for x, y, and z
x = np.linspace(0, 1, 100)
y = np.linspace(0, 1, 100)
z = np.sin(2 * np.pi * x) * np.cos(2 * np.pi * y)

# Compute the outer product of x and y
X, Y = np.outer(x, y)

# Evaluate the z values at each point on the grid
Z = np.sin(2 * np.pi * X) * np.cos(2 * np.pi * Y)

# Plot the contour
plt.contour(X, Y, Z)
plt.xlabel('x')
plt.ylabel('y')
plt.title('2D Contour Plot')
plt.show()``````

This option provides a concise solution by directly computing the outer product of the x and y arrays. It eliminates the need for meshgrid or reshape, making it a more efficient solution.

After evaluating the three options, it is clear that option 3, using numpy.outer, is the best solution. It provides a concise and efficient way to create a 2D contour plot without the need for additional functions or reshaping of arrays.

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### 3 Responses

1. Keegan Cain says:

Option 2 is like trying to fit a square peg in a round hole. Stick with Option 1 or 3!

2. Judah says:

Option 1 looks cool, but Im team Option 2! Reshaping all the way! Whos with me? 🙌

3. Ariyah says:

Option 2 is the way to go! Its like a magic trick for reshaping variables. Love it!