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SIPI (Structure Insensitive Pigment Index)

//
// Structure Intensive Pigment Index 1  (abbrv. SIPI1)
//
// General formula: (800nm - 445nm) / (800nm - 680nm)
//
// URL https://www.indexdatabase.de/db/si-single.php?sensor_id=96&rsindex_id=90
//

let index = (B08 - B01) / (B08 - B04);

return colorBlend(index, [0.5, 1, 1.1, 1.2, 3, 5],
[
  [0,0,0],
  [0,0.5,0],
  [0,1,0],
  [1,1,0],
  [0.8,0.8,0.8],
  [1,1,1]
]);

/*
let index = (B08 - B01) / (B08 - B04);
let min = -32.419;
let max = 33.191;
let zero = 0.0;

// colorBlend will return a color when the index is between min and max and white when it is less than min.
// To see black when it is more than max, uncomment the last line of colorBlend.
// The min/max values were computed automatically and may be poorly specified, feel free to change them to tweak the displayed range.
// This index crosses zero, so a diverging color map is used. To tweak the value of the break in the color map, change the variable 'zero'.

let underflow_color = [1, 1, 1];
let low_color = [208/255, 88/255, 126/255];
let high_color = [241/255, 234/255, 200/255];
let zero_color = [0, 147/255, 146/255];
let overflow_color = [0, 0, 0];

return colorBlend(index, [min, min, zero, max],
[
	underflow_color,
	low_color,
	zero_color, // divergent step at zero
	high_color,
	//overflow_color // uncomment to see overflows
]);
*/

Evaluate and Visualize

General description of the script

The SIPI index maximizes sensitivity to the bulk carotenoids to chlorophyll ratio, while minimizing the impact of the variable canopy structure. It is very useful in areas with high variability in the canopy structure, or leaf area index..

Values description: SIPI values range from 0 to 2, where healthy green vegetation ranges from 0.8 to 1.8.

Description of representative images

SIPI of Rome. Acquired on 8.10.2017.

sipi