AI-generated Key Takeaways
-
Image.arrayMaskcreates a new array image where each pixel is masked by another array image, keeping elements only where the mask is non-zero. -
If the mask image has a single band, it is applied to all bands of the input image; otherwise, the mask and input images must have the same number of bands.
| Usage | Returns |
|---|---|
Image.
arrayMask
(mask)
|
Image |
| Argument | Type | Details |
|---|---|---|
|
this:
input
|
Image | Array image to mask. |
mask
|
Image | Array image to mask with. |
Examples
Code Editor (JavaScript)
// A function to print arrays for a selected pixel in the following examples. function sampArrImg ( arrImg ) { var point = ee . Geometry . Point ([ - 121 , 42 ]); return arrImg . sample ( point , 500 ). first (). get ( 'array' ); } // Create a 1D array image with length 6. var arrayImg1D = ee . Image ([ 0 , 1 , 2 , 4 , 0 , 5 ]). toArray (); print ( '1D array image (pixel)' , sampArrImg ( arrayImg1D )); // [0, 1, 2, 4, 0, 5] // Create a mask using a relational operator to mask values greater than 2. var mask1D = arrayImg1D . lte ( 2 ); print ( '1D mask for greater than value 2 (pixel)' , sampArrImg ( mask1D )); // [1, 1, 1, 0, 1, 0] var arrayImg1DMask = arrayImg1D . arrayMask ( mask1D ); print ( '1D array image mask (pixel)' , sampArrImg ( arrayImg1DMask )); // [0, 1, 2, 0] // Self mask the 1D array image. Value zero will be masked out. var arrayImg1DselfMask = arrayImg1D . arrayMask ( arrayImg1D ); print ( '1D array image self mask (pixel)' , sampArrImg ( arrayImg1DselfMask )); // [1, 2, 4, 5] // Create a 2D array image. var arrayImg2D = arrayImg1D . arrayReshape ( ee . Image ([ 2 , 3 ]). toArray (), 2 ); print ( '2D 2x3 array image (pixel)' , sampArrImg ( arrayImg2D )); // [[0, 1, 2], // [4, 0, 5]] // Slice out a row to use as a column mask. var rowAsMaskForCols = arrayImg2D . arraySlice ( 0 , 1 , 2 ); print ( '2D mask for cols (pixel)' , sampArrImg ( rowAsMaskForCols )); // [[4, 0, 5]] var arrayImg2DMaskCols = arrayImg2D . arrayMask ( rowAsMaskForCols ); print ( '2D array image cols masked (pixel)' , sampArrImg ( arrayImg2DMaskCols )); // [[0, 2], // [4, 5]] // Slice out a column to use as a row mask. var colAsMaskForRows = arrayImg2D . arraySlice ( 1 , 1 , 2 ); print ( '2D mask for rows (pixel)' , sampArrImg ( colAsMaskForRows )); // [[1], // [0]] var arrayImg2DMaskRows = arrayImg2D . arrayMask ( colAsMaskForRows ); print ( '2D array image rows masked (pixel)' , sampArrImg ( arrayImg2DMaskRows )); // [[0, 1, 2]]
import ee import geemap.core as geemap
Colab (Python)
# A function to print arrays for a selected pixel in the following examples. def samp_arr_img ( arr_img ): point = ee . Geometry . Point ([ - 121 , 42 ]) return arr_img . sample ( point , 500 ) . first () . get ( 'array' ) # Create a 1D array image with length 6. array_img_1d = ee . Image ([ 0 , 1 , 2 , 4 , 0 , 5 ]) . toArray () display ( '1D array image (pixel):' , samp_arr_img ( array_img_1d )) # [0, 1, 2, 4, 0, 5] # Create a mask using a relational operator to mask values greater than 2. mask_1d = array_img_1d . lte ( 2 ) display ( '1D mask for greater than value 2 (pixel):' , samp_arr_img ( mask_1d ) ) # [1, 1, 1, 0, 1, 0] array_img1d_mask = array_img_1d . arrayMask ( mask_1d ) display ( '1D array image mask (pixel):' , samp_arr_img ( array_img1d_mask )) # [0, 1, 2, 0] # Self mask the 1D array image. Value zero will be masked out. array_img_1d_self_mask = array_img_1d . arrayMask ( array_img_1d ) display ( '1D array image self mask (pixel):' , samp_arr_img ( array_img_1d_self_mask ) ) # [1, 2, 4, 5] # Create a 2D array image. array_img_2d = array_img_1d . arrayReshape ( ee . Image ([ 2 , 3 ]) . toArray (), 2 ) display ( '2D 2x3 array image (pixel):' , samp_arr_img ( array_img_2d )) # [[0, 1, 2], # [4, 0, 5]] # Slice out a row to use as a column mask. row_as_mask_for_cols = array_img_2d . arraySlice ( 0 , 1 , 2 ) display ( '2D mask for cols (pixel):' , samp_arr_img ( row_as_mask_for_cols )) # [[4, 0, 5]] array_img_2d_mask_cols = array_img_2d . arrayMask ( row_as_mask_for_cols ) display ( '2D array image cols masked (pixel):' , samp_arr_img ( array_img_2d_mask_cols ) ) # [[0, 2], # [4, 5]] # Slice out a column to use as a row mask. col_as_mask_for_rows = array_img_2d . arraySlice ( 1 , 1 , 2 ) display ( '2D mask for rows (pixel):' , samp_arr_img ( col_as_mask_for_rows )) # [[1], # [0]] array_img_2d_mask_rows = array_img_2d . arrayMask ( col_as_mask_for_rows ) display ( '2D array image rows masked (pixel):' , samp_arr_img ( array_img_2d_mask_rows ) ) # [[0, 1, 2]]
