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Updates an image's mask at all positions where the existing mask is not zero using the value of the image as the new mask value. The output image retains the metadata and footprint of the input image.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2023-10-06 UTC."],[[["\u003cp\u003eThe \u003ccode\u003eselfMask()\u003c/code\u003e method updates an image's mask using its own pixel values, where existing mask values of zero remain masked.\u003c/p\u003e\n"],["\u003cp\u003eThis effectively masks out areas where the image has a value of zero, making those pixels invalid.\u003c/p\u003e\n"],["\u003cp\u003eThe output image retains the original metadata and footprint.\u003c/p\u003e\n"],["\u003cp\u003e\u003ccode\u003eselfMask()\u003c/code\u003e is commonly used with Boolean masks to isolate areas of interest based on specific pixel values.\u003c/p\u003e\n"]]],["The `selfMask()` method updates an image's mask. It uses the image's pixel values as the new mask, keeping only areas where the existing mask is non-zero. Areas where the image value is zero are removed, becoming invalid. The output image retains the input's metadata and footprint. The example demonstrates creating a land/water mask and then applying `selfMask()` to remove areas with a value of zero, representing water.\n"],null,["# ee.Image.selfMask\n\nUpdates an image's mask at all positions where the existing mask is not zero using the value of the image as the new mask value. The output image retains the metadata and footprint of the input image.\n\n\u003cbr /\u003e\n\n| Usage | Returns |\n|--------------------|---------|\n| Image.selfMask`()` | Image |\n\n| Argument | Type | Details |\n|---------------|-------|--------------------------------|\n| this: `image` | Image | The image to mask with itself. |\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');\nvar trueColorViz = {\n bands: ['B4', 'B3', 'B2'],\n min: 0,\n max: 2700,\n gamma: 1.3\n};\nprint('Sentinel-2 image', img);\nMap.setCenter(-122.36, 37.47, 10);\nMap.addLayer(img, trueColorViz, 'Sentinel-2 image');\n\n// Create a Boolean land mask from the SWIR1 band; water is value 0, land is 1.\nvar landMask = img.select('B11').gt(100);\nprint('Land mask', landMask);\nMap.addLayer(landMask, {palette: ['blue', 'lightgreen']}, 'Land mask');\n\n// Mask the land mask by itself; pixel values equal to 0 (water) become invalid.\nvar landMaskMasked = landMask.selfMask();\nprint('Land mask, masked', landMaskMasked);\nMap.addLayer(landMaskMasked, {palette: ['gold']}, 'Land mask, masked');\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')\ntrue_color_viz = {\n 'bands': ['B4', 'B3', 'B2'],\n 'min': 0,\n 'max': 2700,\n 'gamma': 1.3,\n}\ndisplay('Sentinel-2 image', img)\nm = geemap.Map()\nm.set_center(-122.36, 37.47, 10)\nm.add_layer(img, true_color_viz, 'Sentinel-2 image')\n\n# Create a Boolean land mask from the SWIR1 band water is value 0, land is 1.\nland_mask = img.select('B11').gt(100)\ndisplay('Land mask', land_mask)\nm.add_layer(land_mask, {'palette': ['blue', 'lightgreen']}, 'Land mask')\n\n# Mask the land mask by itself pixel values equal to 0 (water) become invalid.\nland_mask_masked = land_mask.selfMask()\ndisplay('Land mask, masked', land_mask_masked)\nm.add_layer(land_mask_masked, {'palette': ['gold']}, 'Land mask, masked')\nm\n```"]]
