ee.Reducer.minMax

यह एक Reducer ऑब्जेक्ट दिखाता है, जो अपने इनपुट की कम से कम और ज़्यादा से ज़्यादा वैल्यू का हिसाब लगाता है. लागू होने पर, आउटपुट के नाम ये होते हैं: "min", "max".

इस्तेमाल	रिटर्न
ee.Reducer.minMax()	रेड्यूसर

कोई आर्ग्युमेंट नहीं.

उदाहरण

कोड एडिटर (JavaScript)

// The ee.Reducer.minMax() function calculates the minimum and maximum values
// for its input data. It is a versatile reducer that can be applied
// to various Earth Engine object classes, as demonstrated in the following
// examples.
//
// 1. Lists (list reduction)
// Find the min and max values in an ee.List.
var list = ee.List([1, 2, 3, 4]);
var minMaxList = list.reduce(ee.Reducer.minMax());
print('ee.List min and max:', minMaxList);  // { "max": 4, "min": 1 }

// 2. Arrays (array reduction)
// Find the min and max values in an ee.Array.
var array = ee.Array([[1], [2], [3], [4]]);
var minMaxArray = array.reduce(ee.Reducer.minMax(), [0], 1);
print('ee.Array min and max:', minMaxArray);  // [[1, 4]]

// 3. Collections (metadata reduction)
// Find the min and max values of a collection property.
var dataset = ee.ImageCollection('NOAA/GOES/19/MCMIPF').limit(1000);

var range = dataset.reduceColumns(ee.Reducer.minMax(), ['system:time_start']);
print(
    'ee.ImageCollection property (system:time_start) min and max:',
    ee.Date(range.get('min')),  // Date (2024-10-10 20:40:20)
    ee.Date(range.get('max'))   // Date (2024-10-17 19:20:20)
);

// 4. Images (spatial reduction)
// Find the min and max pixel values within an image region.
var image = ee.Image('MODIS/061/MOD13A2/2021_01_01').select('NDVI');
var region = ee.Geometry.Point([-122.443, 37.753]).buffer(10000).bounds();

var pixelStats = image.reduceRegion({
  reducer: ee.Reducer.minMax(),
  geometry: region,
  scale: 1000,
});
print('ee.Image pixel min and max in region:', pixelStats);

// 5. Images (neighborhood reduction)
// Find the min and max values in the local neighborhood of each pixel.
var localMinMax = image.reduceNeighborhood({
  reducer: ee.Reducer.minMax(),
  kernel: ee.Kernel.square(3),
});
print('ee.Image neighborhood min and max bands:', localMinMax.bandNames());
Map.setCenter(-122.443, 37.753, 9);
Map.addLayer(
    localMinMax, {bands: ['NDVI_min'], min: 0, max: 9000}, 'Local Min NDVI');
Map.addLayer(
    localMinMax, {bands: ['NDVI_max'], min: 0, max: 9000}, 'Local Max NDVI');

// 6. FeatureCollections (zonal reduction)
// Find the min and max pixel values for multiple features.
var points = ee.FeatureCollection([
  ee.Feature(ee.Geometry.Point([-122.443, 37.753]), {label: 'Point 1'}),
  ee.Feature(ee.Geometry.Point([-122.158, 37.559]), {label: 'Point 2'})
]);

var zonalStats = image.reduceRegions({
  collection: points.map(function(f) {
    return f.buffer(5000);
  }),
  reducer: ee.Reducer.minMax(),
  scale: 1000
});
print('ee.FeatureCollection zonal min and max:', zonalStats);

// 7. ImageCollections (temporal reduction)
// Find the min and max pixel values across an ImageCollection.
var col = ee.ImageCollection('MODIS/061/MOD13A2')
              .filterDate('2021-01-01', '2022-01-01')
              .select('NDVI');

var colMinMax = col.reduce(ee.Reducer.minMax());
print(
    'ee.ImageCollection pixel-wise min and max bands:', colMinMax.bandNames());
Map.addLayer(
    colMinMax, {bands: ['NDVI_min'], min: 0, max: 9000}, 'Temporal Min NDVI');
Map.addLayer(
    colMinMax, {bands: ['NDVI_max'], min: 0, max: 9000}, 'Temporal Max NDVI');