ee.Array.cos

  • Calculates the cosine of each element within an input array, with the input values expected to be in radians.

  • Returns a new array containing the cosine results, maintaining the structure of the input array.

  • Utilizes the standard mathematical definition of cosine, producing results ranging from -1 to 1.

  • Can be applied to single values or large arrays for efficient trigonometric computations in Earth Engine.

  • Usage examples are provided in JavaScript and Python environments with visualizations to aid in comprehension.

 On an element-wise basis, computes the cosine of the input in radians.

UsageReturns
Array.cos()Array
ArgumentTypeDetails
this: inputArrayThe input array.

Examples

Code Editor (JavaScript)

var π = Math.PI;
print(ee.Array([-π]).cos());  // [-1]
print(ee.Array([-π / 2.0]).cos());  // [Almost zero]
print(ee.Array([0]).cos());  // [1]
print(ee.Array([π / 2.0]).cos());  // [Almost zero]
print(ee.Array([π]).cos());  // [-1]

var start = -π;
var end = π;
var points = ee.Array(ee.List.sequence(start, end, null, 50));
var values = points.cos();

// Plot cos() defined above.
var chart = ui.Chart.array.values(values, 0, points)
    .setOptions({
      viewWindow: {min: start, max: end},
      hAxis: {
        title: 'x',
        viewWindowMode: 'maximized',
        ticks: [
          {v: start, f: '-π'},
          {v: 0, f: 0},
          {v: end, f: 'π'}]
      },
      vAxis: {
        title: 'cos(x)',
        ticks: [
          {v: -1, f: -1},
          {v: 0, f: 0},
          {v: 1, f: 1}]
      },
      lineWidth: 1,
      pointSize: 0,
    });
print(chart);

Python setup

See the Python Environment page for information on the Python API and using geemap for interactive development.

import ee
import geemap.core as geemap

Colab (Python)

import math
import altair as alt
import pandas as pd

π = math.pi
display(ee.Array([-π]).cos())  # [-1]
display(ee.Array([-π / 2.0]).cos())  # [Almost zero]
display(ee.Array([0]).cos())  # [1]
display(ee.Array([π / 2.0]).cos())  # [Almost zero]
display(ee.Array([π]).cos())  # [-1]

start = -π
end = π
points = ee.Array(ee.List.sequence(start, end, None, 50))
values = points.cos()

df = pd.DataFrame({'x': points.getInfo(), 'cos(x)': values.getInfo()})

# Plot cos() defined above.
alt.Chart(df).mark_line().encode(
    x=alt.X('x', axis=alt.Axis(values=[start, 0, end])),
    y=alt.Y('cos(x)', axis=alt.Axis(values=[-1, 0, 1]))
)