ee.Image.subtract

针对 image1 和 image2 中每个匹配的波段对，从第一个值中减去第二个值。如果 image1 或 image2 只有一个波段，则会将其与另一张图片中的所有波段进行比较。如果图片具有相同数量的波段，但名称不同，则会按自然顺序成对使用。输出波段的命名方式为：如果两个输入的长度不同，则以较长的输入命名；如果长度相同，则以 image1 的顺序命名。输出像素的类型是输入类型的并集。

用法	返回
Image.subtract(image2)	图片

参数	类型	详细信息
此：image1	图片	从中获取左操作数波段的映像。
image2	图片	从中获取右操作数波段的映像。

示例

代码编辑器 (JavaScript)

// A Sentinel-2 surface reflectance image.
var img = ee.Image('COPERNICUS/S2_SR/20210109T185751_20210109T185931_T10SEG');

// Subset two image bands and display them on the map.
var swir1 = img.select('B11');
var swir2 = img.select('B12');
Map.setCenter(-122.276, 37.456, 12);
Map.addLayer(swir1, {min: 0, max: 3000}, 'swir1');
Map.addLayer(swir2, {min: 0, max: 3000}, 'swir2');

// The following examples demonstrate ee.Image arithmetic methods using two
// single-band ee.Image inputs.
var addition = swir1.add(swir2);
Map.addLayer(addition, {min: 100, max: 6000}, 'addition');

var subtraction = swir1.subtract(swir2);
Map.addLayer(subtraction, {min: 0, max: 1500}, 'subtraction');

var multiplication = swir1.multiply(swir2);
Map.addLayer(multiplication, {min: 1.9e5, max: 9.4e6}, 'multiplication');

var division = swir1.divide(swir2);
Map.addLayer(division, {min: 0, max: 3}, 'division');

var remainder = swir1.mod(swir2);
Map.addLayer(remainder, {min: 0, max: 1500}, 'remainder');

// If a number input is provided as the second argument, it will automatically
// be promoted to an ee.Image object, a convenient shorthand for constants.
var exponent = swir1.pow(3);
Map.addLayer(exponent, {min: 0, max: 2e10}, 'exponent');

Python 设置

如需了解 Python API 和如何使用 geemap 进行交互式开发，请参阅 Python 环境页面。

import ee
import geemap.core as geemap

Colab (Python)

# A Sentinel-2 surface reflectance image.
img = ee.Image('COPERNICUS/S2_SR/20210109T185751_20210109T185931_T10SEG')

# Subset two image bands and display them on the map.
swir_1 = img.select('B11')
swir_2 = img.select('B12')
m = geemap.Map()
m.set_center(-122.276, 37.456, 12)
m.add_layer(swir_1, {'min': 0, 'max': 3000}, 'swir_1')
m.add_layer(swir_2, {'min': 0, 'max': 3000}, 'swir_2')

# The following examples demonstrate ee.Image arithmetic methods using two
# single-band ee.Image inputs.
addition = swir_1.add(swir_2)
m.add_layer(addition, {'min': 100, 'max': 6000}, 'addition')

subtraction = swir_1.subtract(swir_2)
m.add_layer(subtraction, {'min': 0, 'max': 1500}, 'subtraction')

multiplication = swir_1.multiply(swir_2)
m.add_layer(multiplication, {'min': 1.9e5, 'max': 9.4e6}, 'multiplication')

division = swir_1.divide(swir_2)
m.add_layer(division, {'min': 0, 'max': 3}, 'division')

remainder = swir_1.mod(swir_2)
m.add_layer(remainder, {'min': 0, 'max': 1500}, 'remainder')

# If a number input is provided as the second argument, it will automatically
# be promoted to an ee.Image object, a convenient shorthand for constants.
exponent = swir_1.pow(3)
m.add_layer(exponent, {'min': 0, 'max': 2e10}, 'exponent')
m