Cab (Leaf Chlorophyll Content)
//VERSION=3 (auto-converted from 2)
var degToRad = Math.PI / 180;
function evaluatePixelOrig(samples) {
var sample = samples[0];
var b03_norm = normalize(sample.B03, 0, 0.253061520471542);
var b04_norm = normalize(sample.B04, 0, 0.290393577911328);
var b05_norm = normalize(sample.B05, 0, 0.305398915248555);
var b06_norm = normalize(sample.B06, 0.006637972542253, 0.608900395797889);
var b07_norm = normalize(sample.B07, 0.013972727018939, 0.753827384322927);
var b8a_norm = normalize(sample.B8A, 0.026690138082061, 0.782011770669178);
var b11_norm = normalize(sample.B11, 0.016388074192258, 0.493761397883092);
var b12_norm = normalize(sample.B12, 0, 0.493025984460231);
var viewZen_norm = normalize(Math.cos(sample.viewZenithMean * degToRad), 0.918595400582046, 1);
var sunZen_norm = normalize(Math.cos(sample.sunZenithAngles * degToRad), 0.342022871159208, 0.936206429175402);
var relAzim_norm = Math.cos((sample.sunAzimuthAngles - sample.viewAzimuthMean) * degToRad)
var n1 = neuron1(b03_norm,b04_norm,b05_norm,b06_norm,b07_norm,b8a_norm,b11_norm,b12_norm, viewZen_norm,sunZen_norm,relAzim_norm);
var n2 = neuron2(b03_norm,b04_norm,b05_norm,b06_norm,b07_norm,b8a_norm,b11_norm,b12_norm, viewZen_norm,sunZen_norm,relAzim_norm);
var n3 = neuron3(b03_norm,b04_norm,b05_norm,b06_norm,b07_norm,b8a_norm,b11_norm,b12_norm, viewZen_norm,sunZen_norm,relAzim_norm);
var n4 = neuron4(b03_norm,b04_norm,b05_norm,b06_norm,b07_norm,b8a_norm,b11_norm,b12_norm, viewZen_norm,sunZen_norm,relAzim_norm);
var n5 = neuron5(b03_norm,b04_norm,b05_norm,b06_norm,b07_norm,b8a_norm,b11_norm,b12_norm, viewZen_norm,sunZen_norm,relAzim_norm);
var l2 = layer2(n1, n2, n3, n4, n5);
var cab = denormalize(l2, 0.007426692959872, 873.908222110306);
return {
default: [cab / 300]
}
}
function neuron1(b03_norm,b04_norm,b05_norm,b06_norm,b07_norm,b8a_norm,b11_norm,b12_norm, viewZen_norm,sunZen_norm,relAzim_norm) {
var sum =
4.242299670155190
+ 0.400396555256580 * b03_norm
+ 0.607936279259404 * b04_norm
+ 0.137468650780226 * b05_norm
- 2.955866573461640 * b06_norm
- 3.186746687729570 * b07_norm
+ 2.206800751246430 * b8a_norm
- 0.313784336139636 * b11_norm
+ 0.256063547510639 * b12_norm
- 0.071613219805105 * viewZen_norm
+ 0.510113504210111 * sunZen_norm
+ 0.142813982138661 * relAzim_norm;
return tansig(sum);
}
function neuron2(b03_norm,b04_norm,b05_norm,b06_norm,b07_norm,b8a_norm,b11_norm,b12_norm, viewZen_norm,sunZen_norm,relAzim_norm) {
var sum =
- 0.259569088225796
- 0.250781102414872 * b03_norm
+ 0.439086302920381 * b04_norm
- 1.160590937522300 * b05_norm
- 1.861935250269610 * b06_norm
+ 0.981359868451638 * b07_norm
+ 1.634230834254840 * b8a_norm
- 0.872527934645577 * b11_norm
+ 0.448240475035072 * b12_norm
+ 0.037078083501217 * viewZen_norm
+ 0.030044189670404 * sunZen_norm
+ 0.005956686619403 * relAzim_norm;
return tansig(sum);
}
function neuron3(b03_norm,b04_norm,b05_norm,b06_norm,b07_norm,b8a_norm,b11_norm,b12_norm, viewZen_norm,sunZen_norm,relAzim_norm) {
var sum =
+ 3.130392627338360
+ 0.552080132568747 * b03_norm
- 0.502919673166901 * b04_norm
+ 6.105041924966230 * b05_norm
- 1.294386119140800 * b06_norm
- 1.059956388352800 * b07_norm
- 1.394092902418820 * b8a_norm
+ 0.324752732710706 * b11_norm
- 1.758871822827680 * b12_norm
- 0.036663679860328 * viewZen_norm
- 0.183105291400739 * sunZen_norm
- 0.038145312117381 * relAzim_norm;
return tansig(sum);
}
function neuron4(b03_norm,b04_norm,b05_norm,b06_norm,b07_norm,b8a_norm,b11_norm,b12_norm, viewZen_norm,sunZen_norm,relAzim_norm) {
var sum =
+ 0.774423577181620
+ 0.211591184882422 * b03_norm
- 0.248788896074327 * b04_norm
+ 0.887151598039092 * b05_norm
+ 1.143675895571410 * b06_norm
- 0.753968830338323 * b07_norm
- 1.185456953076760 * b8a_norm
+ 0.541897860471577 * b11_norm
- 0.252685834607768 * b12_norm
- 0.023414901078143 * viewZen_norm
- 0.046022503549557 * sunZen_norm
- 0.006570284080657 * relAzim_norm;
return tansig(sum);
}
function neuron5(b03_norm,b04_norm,b05_norm,b06_norm,b07_norm,b8a_norm,b11_norm,b12_norm, viewZen_norm,sunZen_norm,relAzim_norm) {
var sum =
+ 2.584276648534610
+ 0.254790234231378 * b03_norm
- 0.724968611431065 * b04_norm
+ 0.731872806026834 * b05_norm
+ 2.303453821021270 * b06_norm
- 0.849907966921912 * b07_norm
- 6.425315500537270 * b8a_norm
+ 2.238844558459030 * b11_norm
- 0.199937574297990 * b12_norm
+ 0.097303331714567 * viewZen_norm
+ 0.334528254938326 * sunZen_norm
+ 0.113075306591838 * relAzim_norm;
return tansig(sum);
}
function layer2(neuron1, neuron2, neuron3, neuron4, neuron5) {
var sum =
+ 0.463426463933822
- 0.352760040599190 * neuron1
- 0.603407399151276 * neuron2
+ 0.135099379384275 * neuron3
- 1.735673123851930 * neuron4
- 0.147546813318256 * neuron5;
return sum;
}
function normalize(unnormalized, min, max) {
return 2 * (unnormalized - min) / (max - min) - 1;
}
function denormalize(normalized, min, max) {
return 0.5 * (normalized + 1) * (max - min) + min;
}
function tansig(input) {
return 2 / (1 + Math.exp(-2 * input)) - 1;
}
function setup() {
return {
input: [{
bands: [
"B03",
"B04",
"B05",
"B06",
"B07",
"B8A",
"B11",
"B12",
"viewZenithMean",
"viewAzimuthMean",
"sunZenithAngles",
"sunAzimuthAngles"
]
}],
output: [
{
id: "default",
sampleType: "AUTO",
bands: 1
}
]
}
}
function evaluatePixel(sample, scene, metadata, customData, outputMetadata) {
const result = evaluatePixelOrig([sample], [scene], metadata, customData, outputMetadata);
return result[Object.keys(result)[0]];
}Evaluate and Visualize
General description of the script
Cab (leaf cholrophyll content (μg / cm ^ 2)) corresponds to the content of chlorophyll a, chlorophyll b and carotenoids per unit of leaf area. Note that the Cab script is as implemented in SNAP but without input and output validation! Input/output values which are suspect are not reported or changed. Most values, however, do not fall under this category. Visualized as an interval from 0-300. This can be adjusted in the evaluatePixel method.
Description of representative images
Leaf chlorophyl index of Rome. Acquired on 8.10.2017.
