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ee.Image.gt
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如果且僅當 image1 和 image2 中每個相符的波段對，第一個值都大於第二個值，則傳回 1。如果 image1 或 image2 只有 1 個頻帶，則會與另一張圖片中的所有頻帶進行比較。如果圖片的波段數量相同，但名稱不同，系統會依自然順序成對使用。輸出頻帶會以較長的輸入命名，如果長度相同，則會以 image1 的順序命名。輸出像素的類型為布林值。
| 引數 | 類型 | 詳細資料 |
|---|
這個：image1 | 圖片 | 用來擷取左運算元頻帶的圖片。 |
image2 | 圖片 | 系統會從這張圖片擷取右運算元頻帶。 |
範例
程式碼編輯器 (JavaScript)
// Show world oceans in blue and anything higher than the ellipsoid as gray.
// The bedrock layer is generally close to the geoid (sealevel).
var elevation = ee.Image('NOAA/NGDC/ETOPO1').select('bedrock');
var waterLand = elevation.gt(0.0);
var waterLandViz = {palette: ['cadetblue', 'lightgray']};
Map.addLayer(waterLand, waterLandViz, 'water_land');
Python 設定
請參閱
Python 環境頁面，瞭解 Python API 和如何使用 geemap 進行互動式開發。
import ee
import geemap.core as geemap
Colab (Python)
# Show world oceans in blue and anything higher than the ellipsoid as gray.
# The bedrock layer is generally close to the geoid (sealevel).
elevation = ee.Image('NOAA/NGDC/ETOPO1').select('bedrock')
water_land = elevation.gt(0.0)
water_land_viz = {'palette': ['cadetblue', 'lightgray']}
m = geemap.Map()
m.add_layer(water_land, water_land_viz, 'water_land')
m
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上次更新時間：2025-07-26 (世界標準時間)。
[null,null,["上次更新時間：2025-07-26 (世界標準時間)。"],[[["\u003cp\u003eThe \u003ccode\u003egt()\u003c/code\u003e function compares corresponding bands of two images, returning 1 if the first image's band value is greater than the second image's band value, and 0 otherwise.\u003c/p\u003e\n"],["\u003cp\u003eIf the images have different numbers of bands, single-band images are compared against all bands of the multi-band image; if they have the same number of bands but different names, bands are compared in their natural order.\u003c/p\u003e\n"],["\u003cp\u003eThe output is a boolean image with bands named according to the longer input image or, if equal in length, the first image's band names.\u003c/p\u003e\n"],["\u003cp\u003eThis function is useful for creating binary masks based on thresholding, such as identifying areas above sea level in an elevation dataset.\u003c/p\u003e\n"]]],["The function compares corresponding bands between two images (`image1` and `image2`). It returns 1 (true) if `image1`'s band value is greater than `image2`'s; otherwise, it returns 0 (false). If one image has a single band, it's compared against all bands of the other image. If the images have the same amount of bands with differing names, bands are compared sequentially. The output, representing these comparisons, is an image with boolean pixel values, named according to the longer input image's band names, or `image1`'s if they have the same length.\n"],null,["# ee.Image.gt\n\nReturns 1 if and only if the first value is greater than the second 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 boolean.\n\n\u003cbr /\u003e\n\n| Usage | Returns |\n|--------------------|---------|\n| Image.gt`(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// Show world oceans in blue and anything higher than the ellipsoid as gray.\n// The bedrock layer is generally close to the geoid (sealevel).\nvar elevation = ee.Image('NOAA/NGDC/ETOPO1').select('bedrock');\nvar waterLand = elevation.gt(0.0);\nvar waterLandViz = {palette: ['cadetblue', 'lightgray']};\nMap.addLayer(waterLand, waterLandViz, 'water_land');\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# Show world oceans in blue and anything higher than the ellipsoid as gray.\n# The bedrock layer is generally close to the geoid (sealevel).\nelevation = ee.Image('NOAA/NGDC/ETOPO1').select('bedrock')\nwater_land = elevation.gt(0.0)\nwater_land_viz = {'palette': ['cadetblue', 'lightgray']}\nm = geemap.Map()\nm.add_layer(water_land, water_land_viz, 'water_land')\nm\n```"]]
