错误：
这里的时错误原始的代码链接：
https://code.earthengine.google.com/4bf0975a41e14d0c40e01925c6f3cf2a
这里主要的问题时这个单一影像不存在：
ImageCollection (Error)
ImageCollection.load: ImageCollection asset 'LANDSAT/LC08/C01/T1_SR/LC08_221077_20170411' not found (does not exist or caller does not have access).
而表面的问题是
Line 16: nir.subtract is not a function
原始代码：
// Importar imagem Landsat 8 var image = ee.ImageCollection('LANDSAT/LC08/C01/T1_SR/LC08_221077_20170411'); // Centrar mapa Map.setCenter(-46.19804603400004,-12.026968211384917); // Obter bandas espectrais var nir = image.select('B5'); // Infravermelho próximo var red = image.select('B4'); // Vermelho var blue = image.select('B2'); // Azul var green = image.select('B3'); // Verde // Calcular índices de vegetação var ndvi = nir.subtract(red).divide(nir.add(red)).rename('NDVI'); // NDVI var savi = nir.subtract(red).multiply(1.5).divide(nir.add(red).add(0.5)).rename('SAVI'); // SAVI var evi = nir.subtract(red).multiply(2.5).divide(nir.add(red.multiply(6)).subtract(blue.multiply(7.5)).add(1)).rename('EVI'); // EVI var wdvi = nir.subtract(red.multiply(0.87)).rename('WDVI'); // WDVI var gndvi = nir.subtract(green).divide(nir.add(green)).rename('GNDVI'); // GNDVI var grvi = green.divide(red).rename('GRVI'); // GRVI var gci = nir.divide(green).subtract(1).rename('GCI'); // GCI var pri = blue.subtract(green).divide(blue.add(green)).rename('PRI'); // PRI var tvi = nir.subtract(green).multiply(120).subtract(red.subtract(green).multiply(200)).multiply(0.5).add(0.5).rename('TVI'); // TVI var msavi = nir.multiply(2).add(1).subtract(ee.Image.constant(2).multiply(nir.add(1)).pow(2).subtract(ee.Image.constant(8).multiply(nir.subtract(red))).sqrt()).multiply(0.5).rename('MSAVI'); // MSAVI var osavi = nir.subtract(red).divide(nir.add(red).add(0.16)).rename('OSAVI'); // OSAVI var mtvi1 = nir.subtract(green).multiply(1.2).subtract(red.subtract(green).multiply(2.5)).rename('MTVI1'); // MTVI1 var mtvi2 = nir.divide(green).subtract(1.2).multiply(1.5).subtract(red.divide(green).subtract(2.5)).multiply(1.5).rename('MTVI2'); // MTVI2 // Definir parâmetros de visualização dos índices var ndviParams = {min: -1, max: 1, palette: ['blue', 'white', 'green'], bands: 'NDVI'}; // NDVI var saviParams = {min: -1, max: 1, palette: ['blue', 'white', 'green'], bands: 'SAVI'}; // SAVI var eviParams = {min: -1, max: 1, palette: ['blue', 'white', 'green'], bands: 'EVI'}; // EVI var wdviParams = {min: -0.1, max: 0.6, palette: ['blue', 'white', 'green'], bands: 'WDVI'}; // WDVI var gndviParams = {min: -1, max: 1, palette: ['blue', 'white', 'green'], bands: 'GNDVI'}; // GNDVI var grviParams = {min: 0, max: 1, palette: ['red', 'yellow', 'green'], bands: 'GRVI'}; // GRVI var gciParams = {min: -0.5, max: 0.5, palette: ['red', 'white', 'green'], bands: 'GCI'}; // GCI var priParams = {min: -0.5, max: 0.5, palette: ['red', 'white', 'green'], bands: 'PRI'}; // PRI var tviParams = {min: 0, max: 1, palette: ['blue', 'white', 'green'], bands: 'TVI'}; // TVI var msaviParams = {min: -1, max: 1, palette: ['blue', 'white', 'green'], bands: 'MSAVI'}; // MSAVI var osaviParams = {min: -1, max: 1, palette: ['blue', 'white', 'green'], bands: 'OSAVI'}; // OSAVI var mtvi1Params = {min: -1, max: 1, palette: ['blue', 'white', 'green'], bands: 'MTVI1'}; // MTVI1 var mtvi2Params = {min: -1, max: 1, palette: ['blue', 'white', 'green'], bands: 'MTVI2'}; // MTVI2 // Adicionar camadas dos índices ao mapa Map.addLayer(ndvi, ndviParams, 'NDVI'); Map.addLayer(savi, saviParams, 'SAVI'); Map.addLayer(evi, eviParams, 'EVI'); Map.addLayer(wdvi, wdviParams, 'WDVI'); Map.addLayer(gndvi, gndviParams, 'GNDVI'); Map.addLayer(grvi, grviParams, 'GRVI'); Map.addLayer(gci, gciParams, 'GCI'); Map.addLayer(pri, priParams, 'PRI'); Map.addLayer(tvi, tviParams, 'TVI'); Map.addLayer(msavi, msaviParams, 'MSAVI'); Map.addLayer(osavi, osaviParams, 'OSAVI'); Map.addLayer(mtvi1, mtvi1Params, 'MTVI1'); Map.addLayer(mtvi2, mtvi2Params, 'MTVI2');
修改后的代码：
var geometry = /* color: #d63000 */ee.Geometry.Point([-46.19804603400004, -12.026968211384917]); // Importar imagem Landsat 8 //var image = ee.ImageCollection('LANDSAT/LC08/C01/T1_SR/LC08_221077_20170411'); // Centrar mapa Map.setCenter(-46.19804603400004,-12.026968211384917); var image = ee.ImageCollection('LANDSAT/LC08/C01/T1_SR').filterBounds(geometry).first(); // Obter bandas espectrais var nir = image.select('B5'); // Infravermelho próximo var red = image.select('B4'); // Vermelho var blue = image.select('B2'); // Azul var green = image.select('B3'); // Verde // Calcular índices de vegetação var ndvi = nir.subtract(red).divide(nir.add(red)).rename('NDVI'); // NDVI var savi = nir.subtract(red).multiply(1.5).divide(nir.add(red).add(0.5)).rename('SAVI'); // SAVI var evi = nir.subtract(red).multiply(2.5).divide(nir.add(red.multiply(6)).subtract(blue.multiply(7.5)).add(1)).rename('EVI'); // EVI var wdvi = nir.subtract(red.multiply(0.87)).rename('WDVI'); // WDVI var gndvi = nir.subtract(green).divide(nir.add(green)).rename('GNDVI'); // GNDVI var grvi = green.divide(red).rename('GRVI'); // GRVI var gci = nir.divide(green).subtract(1).rename('GCI'); // GCI var pri = blue.subtract(green).divide(blue.add(green)).rename('PRI'); // PRI var tvi = nir.subtract(green).multiply(120).subtract(red.subtract(green).multiply(200)).multiply(0.5).add(0.5).rename('TVI'); // TVI var msavi = nir.multiply(2).add(1).subtract(ee.Image.constant(2).multiply(nir.add(1)).pow(2).subtract(ee.Image.constant(8).multiply(nir.subtract(red))).sqrt()).multiply(0.5).rename('MSAVI'); // MSAVI var osavi = nir.subtract(red).divide(nir.add(red).add(0.16)).rename('OSAVI'); // OSAVI var mtvi1 = nir.subtract(green).multiply(1.2).subtract(red.subtract(green).multiply(2.5)).rename('MTVI1'); // MTVI1 var mtvi2 = nir.divide(green).subtract(1.2).multiply(1.5).subtract(red.divide(green).subtract(2.5)).multiply(1.5).rename('MTVI2'); // MTVI2 // Definir parâmetros de visualização dos índices var ndviParams = {min: -1, max: 1, palette: ['blue', 'white', 'green'], bands: 'NDVI'}; // NDVI var saviParams = {min: -1, max: 1, palette: ['blue', 'white', 'green'], bands: 'SAVI'}; // SAVI var eviParams = {min: -1, max: 1, palette: ['blue', 'white', 'green'], bands: 'EVI'}; // EVI var wdviParams = {min: -0.1, max: 0.6, palette: ['blue', 'white', 'green'], bands: 'WDVI'}; // WDVI var gndviParams = {min: -1, max: 1, palette: ['blue', 'white', 'green'], bands: 'GNDVI'}; // GNDVI var grviParams = {min: 0, max: 1, palette: ['red', 'yellow', 'green'], bands: 'GRVI'}; // GRVI var gciParams = {min: -0.5, max: 0.5, palette: ['red', 'white', 'green'], bands: 'GCI'}; // GCI var priParams = {min: -0.5, max: 0.5, palette: ['red', 'white', 'green'], bands: 'PRI'}; // PRI var tviParams = {min: 0, max: 1, palette: ['blue', 'white', 'green'], bands: 'TVI'}; // TVI var msaviParams = {min: -1, max: 1, palette: ['blue', 'white', 'green'], bands: 'MSAVI'}; // MSAVI var osaviParams = {min: -1, max: 1, palette: ['blue', 'white', 'green'], bands: 'OSAVI'}; // OSAVI var mtvi1Params = {min: -1, max: 1, palette: ['blue', 'white', 'green'], bands: 'MTVI1'}; // MTVI1 var mtvi2Params = {min: -1, max: 1, palette: ['blue', 'white', 'green'], bands: 'MTVI2'}; // MTVI2 // Adicionar camadas dos índices ao mapa Map.addLayer(ndvi, ndviParams, 'NDVI'); Map.addLayer(savi, saviParams, 'SAVI'); Map.addLayer(evi, eviParams, 'EVI'); Map.addLayer(wdvi, wdviParams, 'WDVI'); Map.addLayer(gndvi, gndviParams, 'GNDVI'); Map.addLayer(grvi, grviParams, 'GRVI'); Map.addLayer(gci, gciParams, 'GCI'); Map.addLayer(pri, priParams, 'PRI'); Map.addLayer(tvi, tviParams, 'TVI'); Map.addLayer(msavi, msaviParams, 'MSAVI'); Map.addLayer(osavi, osaviParams, 'OSAVI'); Map.addLayer(mtvi1, mtvi1Params, 'MTVI1'); Map.addLayer(mtvi2, mtvi2Params, 'MTVI2');
