Al contrario del precedente post https://debiaonoldcomputers.blogspot.com/2026/02/analisi-multitemporale-ndvi-con-google.html qui l'idea e' di creare una mappa di NDVI al posto della serie tempo per vedere anomalie spaziali
Landsat 8
// 1. Define the Study Area
var areaOfInterest =
/* color: #d63000 */
/* displayProperties: [
{
"type": "rectangle"
}
] */
ee.Geometry.Polygon(
[[[10.904865172222156, 43.01615135702198],
[10.904865172222156, 43.00648615894694],
[10.925807860210437, 43.00648615894694],
[10.925807860210437, 43.01615135702198]]], null, false);// 2. Pre-processing Function for Landsat 8
var processL8 = function(image) {
var opticalBands = image.select('SR_B.').multiply(0.0000275).add(-0.2);
var ndvi = opticalBands.normalizedDifference(['SR_B5', 'SR_B4']).rename('NDVI');
return image.addBands(ndvi).select('NDVI');
};
// 3. Load 2025 Median NDVI
var ndvi2025 = ee.ImageCollection("LANDSAT/LC08/C02/T1_L2")
.filterBounds(areaOfInterest)
.filterDate('2025-01-01', '2025-12-31')
.map(processL8)
.median()
.clip(areaOfInterest);
// 4. Visualization Parameters
var palette = [
'#FFFFFF', '#CE7E45', '#FCD163', '#66A000', '#207401', '#056201', '#011301'
];
var ndviViz = {min: 0, max: 0.9, palette: palette};
// 5. Display the Map
Map.addLayer(ndvi2025, ndviViz, 'NDVI Median 2025');
// --- 6. ADDING THE LEGEND ---
// Create the legend panel
var legend = ui.Panel({
style: {
position: 'bottom-left',
padding: '8px 15px'
}
});
// Create legend title
var legendTitle = ui.Label({
value: 'NDVI Index (2025)',
style: {fontWeight: 'bold', fontSize: '16px', margin: '0 0 4px 0', padding: '0'}
});
legend.add(legendTitle);
// Helper function to create rows in the legend
var makeRow = function(color, name) {
var colorBox = ui.Label({
style: {
backgroundColor: color,
padding: '8px',
margin: '0 0 4px 0'
}
});
var description = ui.Label({
value: name,
style: {margin: '0 0 4px 6px'}
});
return ui.Panel({
widgets: [colorBox, description],
layout: ui.Panel.Layout.Flow('horizontal')
});
};
// Define labels for the palette colors
var names = ['Low/No Veg (< 0.1)', 'Soil / Sparse', 'Moderate Veg', 'Dense Veg', 'Healthy Forest', 'Peak Vigour (> 0.8)'];
var colors = ['#FFFFFF', '#CE7E45', '#FCD163', '#66A000', '#207401', '#011301'];
// Add rows to legend
for (var i = 0; i < 6; i++) {
legend.add(makeRow(colors[i], names[i]));
}
// Add legend to the map
Map.add(legend);
Export.image.toDrive({
image: ndvi2025, // The variable name of your NDVI map
description: 'NDVI_2025_Tuscany',
folder: 'EarthEngine_Exports', // Name of the folder in your Google Drive
fileNamePrefix: 'NDVI_2025_Site',
region: areaOfInterest, // Export only the area inside your polygon
scale: 30, // Landsat resolution is 30 meters
crs: 'EPSG:4326', // Standard Coordinate Reference System (WGS84)
fileFormat: 'GeoTIFF',
formatOptions: {
cloudOptimized: true // Makes the file easier to open in QGIS/ArcGIS
}
});
Landsat 7
// 1. Define the Study Area
var areaOfInterest =
/* color: #d63000 */
/* displayProperties: [
{
"type": "rectangle"
}
] */
ee.Geometry.Polygon(
[[[10.904865172222156, 43.01615135702198],
[10.904865172222156, 43.00648615894694],
[10.925807860210437, 43.00648615894694],
[10.925807860210437, 43.01615135702198]]], null, false);
// 2. Pre-processing Function for Landsat 8
var processL8 = function(image) {
var opticalBands = image.select('SR_B.').multiply(0.0000275).add(-0.2);
var ndvi = opticalBands.normalizedDifference(['SR_B5', 'SR_B4']).rename('NDVI');
return image.addBands(ndvi).select('NDVI');
};
// 3. Load 2025 Median NDVI
var l7_2005 = ee.ImageCollection("LANDSAT/LE07/C02/T1_L2")
.filterBounds(areaOfInterest)
.filterDate('2005-01-01', '2005-12-31')
.map(function(image) {
var opticalBands = image.select('SR_B.').multiply(0.0000275).add(-0.2);
// Landsat 7 NDVI: (B4 - B3) / (B4 + B3)
var ndvi = opticalBands.normalizedDifference(['SR_B4', 'SR_B3']).rename('NDVI');
return image.addBands(ndvi).select('NDVI');
})
.median() // Create a clean composite for the year
.clip(areaOfInterest);
// 4. Visualization Parameters
var palette = [
'#FFFFFF', '#CE7E45', '#FCD163', '#66A000', '#207401', '#056201', '#011301'
];
var ndviViz = {min: 0, max: 0.9, palette: palette};
// 5. Display the Map
Map.addLayer(l7_2005, ndviViz, 'NDVI Median 2005');
// --- 6. ADDING THE LEGEND ---
// Create the legend panel
var legend = ui.Panel({
style: {
position: 'bottom-left',
padding: '8px 15px'
}
});
// Create legend title
var legendTitle = ui.Label({
value: 'NDVI Index (2025)',
style: {fontWeight: 'bold', fontSize: '16px', margin: '0 0 4px 0', padding: '0'}
});
legend.add(legendTitle);
// Helper function to create rows in the legend
var makeRow = function(color, name) {
var colorBox = ui.Label({
style: {
backgroundColor: color,
padding: '8px',
margin: '0 0 4px 0'
}
});
var description = ui.Label({
value: name,
style: {margin: '0 0 4px 6px'}
});
return ui.Panel({
widgets: [colorBox, description],
layout: ui.Panel.Layout.Flow('horizontal')
});
};
// Define labels for the palette colors
var names = ['Low/No Veg (< 0.1)', 'Soil / Sparse', 'Moderate Veg', 'Dense Veg', 'Healthy Forest', 'Peak Vigour (> 0.8)'];
var colors = ['#FFFFFF', '#CE7E45', '#FCD163', '#66A000', '#207401', '#011301'];
// Add rows to legend
for (var i = 0; i < 6; i++) {
legend.add(makeRow(colors[i], names[i]));
}
// Add legend to the map
Map.add(legend);
Export.image.toDrive({
image: l7_2005, // Updated to the 2005 variable
description: 'NDVI_L7_2005_Tuscany',
folder: 'EarthEngine_Exports',
fileNamePrefix: 'NDVI_Landsat7_2005',
region: areaOfInterest,
scale: 30,
crs: 'EPSG:4326',
fileFormat: 'GeoTIFF',
formatOptions: {
cloudOptimized: true
}
});
