ee.Array.mod

  • Array.mod() calculates the element-wise remainder of the division between two input arrays.

  • The function takes two arrays, left and right, as input, representing the dividend and divisor respectively.

  • It returns a new array containing the remainders of each element-wise division.

  • The function supports both integer and floating-point values.

  • Array.mod() can be used to generate periodic patterns like square waves.

 On an element-wise basis, calculates the remainder of the first value divided by the second.

UsageReturns
Array.mod(right)Array
ArgumentTypeDetails
this: leftArrayThe left-hand value.
rightArrayThe right-hand value.

Examples

Code Editor (JavaScript)

var empty = ee.Array([], ee.PixelType.int8());
print(empty.mod(empty));  // []

print(ee.Array([0, 0]).mod(ee.Array([-1, 2])));  // [0,0]
print(ee.Array([0, 1, 2, 3, 4]).mod(ee.Array([1, 1, 1, 1, 1])));  // [0,0,0,0,0]
print(ee.Array([0, 1, 2, 3, 4]).mod(ee.Array([2, 2, 2, 2, 2])));  // [0,1,0,1,0]
print(ee.Array([0, 1, 7, 8, 9]).mod(ee.Array([8, 8, 8, 8, 8])));  // [0,1,7,0,1]
print(ee.Array([-1, -7, -8, -9]).mod(ee.Array([8, 8, 8, 8])));  // [-1,-7,0,-1]

print(ee.Array([8, 8, 8, 8]).mod(ee.Array([-1, -7, -8, -9])));  // [0,1,0,8]

print(ee.Array([2.5]).mod(ee.Array([1.2])));  // [0.10000000000000009]

// Generate a square wave graph using mod.
var start = -10;
var end = 10;
var numElements = 1000;
var stepSize = 2;

var points = ee.Array(ee.List.sequence(start, end, null, numElements));
var modValues = ee.Array([stepSize]).repeat(0, numElements);
var values = points.mod(modValues).floor();

// Plot mod().floor() defined above.
// Generate a square wave that is different for negative and positive values.
var chart = ui.Chart.array.values(values, 0, points)
    .setOptions({
      viewWindow: {min: start, max: end},
      hAxis: {
        title: 'x',
        viewWindowMode: 'maximized'
      },
      vAxis: {
        title: 'mod().floor()',
        ticks: [{v: -3}, {v: -2}, {v: -1}, {v: 0}, {v: 1}, {v: 2}]
      },
      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 altair as alt
import pandas as pd

empty = ee.Array([], ee.PixelType.int8())
display(empty.mod(empty))  # []

display(ee.Array([0, 0]).mod(ee.Array([-1, 2])))  # [0,0]

# [0,0,0,0,0]
display(ee.Array([0, 1, 2, 3, 4]).mod(ee.Array([1, 1, 1, 1, 1])))

# [0,1,0,1,0]
display(ee.Array([0, 1, 2, 3, 4]).mod(ee.Array([2, 2, 2, 2, 2])))

# [0,1,7,0,1]
display(ee.Array([0, 1, 7, 8, 9]).mod(ee.Array([8, 8, 8, 8, 8])))

# [-1,-7,0,-1]
display(ee.Array([-1, -7, -8, -9]).mod(ee.Array([8, 8, 8, 8])))

# [0,1,0,8]
display(ee.Array([8, 8, 8, 8]).mod(ee.Array([-1, -7, -8, -9])))

display(ee.Array([2.5]).mod(ee.Array([1.2])))  # [0.10000000000000009]

# Generate a square wave graph using mod.
start = -10
end = 10
num_elements = 1000
step_size = 2

points = ee.Array(ee.List.sequence(start, end, None, num_elements))
mod_values = ee.Array([step_size]).repeat(0, num_elements)
values = points.mod(mod_values).floor()

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

# Plot mod().floor() defined above.
# Generate a square wave that is different for negative and positive values.
alt.Chart(df).mark_line().encode(
    x=alt.X('x'),
    y=alt.Y('mod()', axis=alt.Axis(values=[-3, -2, -1, 0, 1, 2]))
)