The MYD13A1 V6 product provides a Vegetation Index (VI) value at a per pixel basis. There are two primary vegetation layers. The first is the Normalized Difference Vegetation Index (NDVI) which is referred to as the continuity index to the existing National Oceanic and Atmospheric Administration-Advanced Very High Resolution Radiometer (NOAA-AVHRR) derived NDVI. The second vegetation layer is the Enhanced Vegetation Index (EVI) that minimizes canopy background variations and maintains sensitivity over dense vegetation conditions. The EVI also uses the blue band to remove residual atmosphere contamination caused by smoke and sub-pixel thin cloud clouds. The MODIS NDVI and EVI products are computed from atmospherically corrected bi-directional surface reflectances that have been masked for water, clouds, heavy aerosols, and cloud shadows.
MYD13A1 V6产品在每个像素的基础上提供植被指数(VI)值。有两个主要的植被层。第一个是归一化植被指数(NDVI),它被称为现有的国家海洋和大气管理局-高级甚高分辨率辐射计(NOAA-AVHRR)得出的NDVI的连续性指数。第二个植被层是增强植被指数(EVI),它将树冠背景变化降到最低,并保持对茂密植被条件的敏感性。EVI还使用蓝色波段来消除由烟雾和亚像素薄云造成的残留大气污染。MODIS NDVI和EVI产品是由经过大气校正的双向表面反射率计算出来的,这些反射率已经屏蔽了水、云、重气溶胶和云影。
Documentation:
Dataset Availability
2002-07-04T00:00:00 - 2021-09-06T00:00:00
Dataset Provider
NASA LP DAAC at the USGS EROS Center
Collection Snippet
Copied
ee.ImageCollection("MODIS/006/MYD13A1")
Resolution
500 meters
Bands Table
Name | Description | Min | Max | Units | Wavelength | Scale |
NDVI | Normalized Difference Vegetation Index | -2000 | 10000 | 0.0001 | ||
EVI | Enhanced Vegetation Index | -2000 | 10000 | 0.0001 | ||
DetailedQA | VI quality indicators | 0 | ||||
DetailedQA Bitmask |
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sur_refl_b01 | Red surface reflectance | 0 | 10000 | 645nm | 0.0001 | |
sur_refl_b02 | NIR surface reflectance | 0 | 10000 | 858nm | 0.0001 | |
sur_refl_b03 | Blue surface reflectance | 0 | 10000 | 469nm | 0.0001 | |
sur_refl_b07 | MIR surface reflectance | 0 | 10000 | 2130nm/2105 - 2155nm | 0.0001 | |
ViewZenith | View zenith angle | 0 | 18000 | Degrees | 0.01 | |
SolarZenith | Solar zenith angle | 0 | 18000 | Degrees | 0.01 | |
RelativeAzimuth | Relative azimuth angle | -18000 | 18000 | Degrees | 0.01 | |
DayOfYear | Julian day of year | 1 | 366 | 0 | ||
SummaryQA | Quality reliability of VI pixel | 0 | ||||
SummaryQA Bitmask |
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使用说明:
MODIS data and products acquired through the LP DAAC have no restrictions on subsequent use, sale, or redistribution.
引用:
代码:
var dataset = ee.ImageCollection('MODIS/006/MYD13A1') .filter(ee.Filter.date('2018-01-01', '2018-05-01')); var ndvi = dataset.select('NDVI'); var ndviVis = { min: 0.0, max: 9000.0, palette: [ 'FFFFFF', 'CE7E45', 'DF923D', 'F1B555', 'FCD163', '99B718', '74A901', '66A000', '529400', '3E8601', '207401', '056201', '004C00', '023B01', '012E01', '011D01', '011301' ], }; Map.setCenter(6.746, 46.529, 2); Map.addLayer(ndvi, ndviVis, 'NDVI');