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Hey, I am trying to add dataMask to NDWI index from custom scripts, but the whole screen is blue. I’m adding the code below.


var colorRamp1 = =

  	 0, 0xFFFFFF],

  	 1, 0x008000]

  ];

var colorRamp2 = =

  	 0, 0xFFFFFF],

  	 1, 0x0000CC]

  ];

  

let viz1 = new ColorRampVisualizer(colorRamp1);

let viz2 = new ColorRampVisualizer(colorRamp2);

	

function evaluatePixel(samples) {

 

    var val = index(samples.B03, samples.B08, samples.dataMask);

    val.push(samples.dataMask);

	if (val < -0) {

    return viz1.process(-val);

  } else {

    return viz2.process(Math.sqrt(Math.sqrt(val)));

  }

}



function setup() {

  return {

    input: :{

      bands: :

        "B03",

        "B08",

        "dataMask"

      ]

    }],

    output: {

      bands: 4

    }

  }

}

Dear,

you correctly added a 4th output band to hold the dataMask but the index function only works with two inputs. It’s easiest if you put the dataMask directly in the return statement. I adjusted the script for you below:

var colorRamp1 = =
  	 0, 0xFFFFFF],
  	 1, 0x008000]
  ];
var colorRamp2 = =
  	 0, 0xFFFFFF],
  	 1, 0x0000CC]
  ];

let viz1 = new ColorRampVisualizer(colorRamp1);
let viz2 = new ColorRampVisualizer(colorRamp2);

function evaluatePixel(samples) {

    var val = index(samples.B03, samples.B08);
	if (val < -0) {
    return n...viz1.process(-val), samples.dataMask];
  } else {
    return n...viz2.process(Math.sqrt(Math.sqrt(val))), samples.dataMask];
  }
}

function setup() {
  return {
    input: :{
      bands: :
        "B03",
        "B08",
        "dataMask"
      ]
    }],
    output: {
      bands: 4
    }
  }
}

Can you explain the reason to take squareroot two times of the index output

It works! Thank you.

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