ee.Image.subtract
קל לארגן דפים בעזרת אוספים
אפשר לשמור ולסווג תוכן על סמך ההעדפות שלך.
Subtracts the second value from the first for each matched pair of bands in image1 and image2. אם לאחת מהתמונות (image1 או image2) יש רק פס אחד, היא תשמש להשוואה עם כל הפסים בתמונה השנייה. אם לתמונות יש אותו מספר של פסים, אבל לא אותם שמות, המערכת משתמשת בהן בזוגות לפי הסדר הטבעי. שמות הפסים בפלט נקבעים לפי השם של הקלט הארוך מבין השניים, או לפי הסדר של image1 אם האורך שלהם זהה. סוג הפיקסלים בפלט הוא איחוד של סוגי הקלט.
| שימוש | החזרות |
|---|
Image.subtract(image2) | תמונה |
| ארגומנט | סוג | פרטים |
|---|
זה: image1 | תמונה | התמונה שממנה נלקחים הפסים של האופרנד השמאלי. |
image2 | תמונה | התמונה שממנה נלקחים הפסים של האופרנד הימני. |
דוגמאות
עורך הקוד (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');
הגדרת Python
מידע על Python API ועל שימוש ב-geemap לפיתוח אינטראקטיבי מופיע בדף
Python Environment.
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
אלא אם צוין אחרת, התוכן של דף זה הוא ברישיון Creative Commons Attribution 4.0 ודוגמאות הקוד הן ברישיון Apache 2.0. לפרטים, ניתן לעיין במדיניות האתר Google Developers. Java הוא סימן מסחרי רשום של חברת Oracle ו/או של השותפים העצמאיים שלה.
עדכון אחרון: 2025-07-26 (שעון UTC).
[null,null,["עדכון אחרון: 2025-07-26 (שעון UTC)."],[[["\u003cp\u003e\u003ccode\u003esubtract()\u003c/code\u003e subtracts the pixel values of two images, band-by-band.\u003c/p\u003e\n"],["\u003cp\u003eIt handles single-band images and multi-band images with potentially different band names.\u003c/p\u003e\n"],["\u003cp\u003eOutput band names and pixel type are determined based on the input images.\u003c/p\u003e\n"],["\u003cp\u003eThe function returns a new \u003ccode\u003eImage\u003c/code\u003e object representing the result of the subtraction.\u003c/p\u003e\n"],["\u003cp\u003eThis method is useful for various image processing tasks like change detection or calculating spectral indices.\u003c/p\u003e\n"]]],["The `subtract` method computes the difference between two images (`image1` and `image2`). It subtracts corresponding bands pairwise. If one image has a single band, it's subtracted from all bands of the other image. When images have different band names but the same count, they're matched in order. Output bands are named after the longer input's band names, with the pixel type as a union of the input types. The code also gives examples of usage with `add`, `multiply`, `divide`, `mod`, and `pow`.\n"],null,["# ee.Image.subtract\n\nSubtracts the second value from the first for each matched pair of bands in image1 and image2. If either image1 or image2 has only 1 band, then it is used against all the bands in the other image. If the images have the same number of bands, but not the same names, they're used pairwise in the natural order. The output bands are named for the longer of the two inputs, or if they're equal in length, in image1's order. The type of the output pixels is the union of the input types.\n\n\u003cbr /\u003e\n\n| Usage | Returns |\n|--------------------------|---------|\n| Image.subtract`(image2)` | Image |\n\n| Argument | Type | Details |\n|----------------|-------|---------------------------------------------------------|\n| this: `image1` | Image | The image from which the left operand bands are taken. |\n| `image2` | Image | The image from which the right operand bands are taken. |\n\nExamples\n--------\n\n### Code Editor (JavaScript)\n\n```javascript\n// A Sentinel-2 surface reflectance image.\nvar img = ee.Image('COPERNICUS/S2_SR/20210109T185751_20210109T185931_T10SEG');\n\n// Subset two image bands and display them on the map.\nvar swir1 = img.select('B11');\nvar swir2 = img.select('B12');\nMap.setCenter(-122.276, 37.456, 12);\nMap.addLayer(swir1, {min: 0, max: 3000}, 'swir1');\nMap.addLayer(swir2, {min: 0, max: 3000}, 'swir2');\n\n// The following examples demonstrate ee.Image arithmetic methods using two\n// single-band ee.Image inputs.\nvar addition = swir1.add(swir2);\nMap.addLayer(addition, {min: 100, max: 6000}, 'addition');\n\nvar subtraction = swir1.subtract(swir2);\nMap.addLayer(subtraction, {min: 0, max: 1500}, 'subtraction');\n\nvar multiplication = swir1.multiply(swir2);\nMap.addLayer(multiplication, {min: 1.9e5, max: 9.4e6}, 'multiplication');\n\nvar division = swir1.divide(swir2);\nMap.addLayer(division, {min: 0, max: 3}, 'division');\n\nvar remainder = swir1.mod(swir2);\nMap.addLayer(remainder, {min: 0, max: 1500}, 'remainder');\n\n// If a number input is provided as the second argument, it will automatically\n// be promoted to an ee.Image object, a convenient shorthand for constants.\nvar exponent = swir1.pow(3);\nMap.addLayer(exponent, {min: 0, max: 2e10}, 'exponent');\n```\nPython setup\n\nSee the [Python Environment](/earth-engine/guides/python_install) page for information on the Python API and using\n`geemap` for interactive development. \n\n```python\nimport ee\nimport geemap.core as geemap\n```\n\n### Colab (Python)\n\n```python\n# A Sentinel-2 surface reflectance image.\nimg = ee.Image('COPERNICUS/S2_SR/20210109T185751_20210109T185931_T10SEG')\n\n# Subset two image bands and display them on the map.\nswir_1 = img.select('B11')\nswir_2 = img.select('B12')\nm = geemap.Map()\nm.set_center(-122.276, 37.456, 12)\nm.add_layer(swir_1, {'min': 0, 'max': 3000}, 'swir_1')\nm.add_layer(swir_2, {'min': 0, 'max': 3000}, 'swir_2')\n\n# The following examples demonstrate ee.Image arithmetic methods using two\n# single-band ee.Image inputs.\naddition = swir_1.add(swir_2)\nm.add_layer(addition, {'min': 100, 'max': 6000}, 'addition')\n\nsubtraction = swir_1.subtract(swir_2)\nm.add_layer(subtraction, {'min': 0, 'max': 1500}, 'subtraction')\n\nmultiplication = swir_1.multiply(swir_2)\nm.add_layer(multiplication, {'min': 1.9e5, 'max': 9.4e6}, 'multiplication')\n\ndivision = swir_1.divide(swir_2)\nm.add_layer(division, {'min': 0, 'max': 3}, 'division')\n\nremainder = swir_1.mod(swir_2)\nm.add_layer(remainder, {'min': 0, 'max': 1500}, 'remainder')\n\n# If a number input is provided as the second argument, it will automatically\n# be promoted to an ee.Image object, a convenient shorthand for constants.\nexponent = swir_1.pow(3)\nm.add_layer(exponent, {'min': 0, 'max': 2e10}, 'exponent')\nm\n```"]]
