NDVI from the VJ113A3 product over Brazil during July 2023.
View full-size imageThe NOAA-20 Visible Infrared Imaging Radiometer Suite (VIIRS) Vegetation Indices (VJ113A3) Version 2 data product provides vegetation indices by a process of selecting the best available pixel over a monthly acquisition period at 1 kilometer (km) resolution. The VJ113 data products are designed after the Moderate Resolution Imaging Spectroradiometer (MODIS) Terra and Aqua Vegetation Indices product suite to promote the continuity of the Earth Observation System (EOS) mission.
The VJ113 algorithm process produces three vegetation indices: The Normalized Difference Vegetation Index (NDVI), the Enhanced Vegetation Index (EVI), and the Enhanced Vegetation Index-2 (EVI2). NDVI is one of the longest continual remotely sensed time series observations, using both the red and near-infrared (NIR) bands. EVI is a slightly different vegetation index that is more sensitive to canopy cover, while NDVI is more sensitive to chlorophyll. EVI2 is a reformation of the standard 3-band EVI, using the red band and NIR band. This reformation addresses arising issues when comparing VIIRS EVI to other EVI models that do not include a blue band. EVI2 will eventually become the standard EVI.
Along with the three Vegetation Indices layers, this product also includes layers for NIR reflectance; three shortwave infrared (SWIR) reflectance; red, blue, and green reflectance; pixel reliability; pixel reliability; relative azimuth, view, and sun angles; and a quality layer. Two low resolution browse images are also available for each VJ113A3 product: EVI and NDVI.
More details can be found in this VIIRS Land V2 Changes document.
Validation at stage 1 has been achieved for the VIIRS Vegetation Index (VI) product suite. Visit VIIRS Land Product Quality Assessment Product Maturity for information on product maturity status.
Characteristic | Description |
---|---|
Collection | NOAA-20 VIIRS |
DOI | 10.5067/VIIRS/VJ113A3.002 |
File Size | ~45.7 MB |
Temporal Resolution | Monthly |
Temporal Extent | 2018-01-01 to Present |
Spatial Extent | Global |
Coordinate System | Sinusoidal |
Datum | N/A |
File Format | HDF-EOS5 |
Geographic Dimensions | 1200 km x 1200 km |
Characteristic | Description |
---|---|
Number of Science Dataset (SDS) Layers | 15 |
Columns/Rows | 1200 x 1200 |
Pixel Size | 1000 m |
SDS Name | Description | Units | Data Type | Fill Value | No Data Value | Valid Range | Scale Factor |
---|---|---|---|---|---|---|---|
1 km monthly EVI | 1 km monthly EVI | EVI | 16-bit signed integer | -15000, -13000 | N/A | -10000 to 10000 | 10000 |
1 km monthly EVI2 | 1 km monthly EVI2 | EVI2 | 16-bit signed integer | -15000, -13000 | N/A | -10000 to 10000 | 10000 |
1 km monthly NDVI | 1 km monthly NDVI | NDVI | 16-bit signed integer | -15000, -13000 | N/A | -10000 to 10000 | 10000 |
1 km monthly NIR reflectance | 1 km monthly NIR reflectance (846–885 nm) | N/A | 16-bit signed integer | -1000 | N/A | 0 to 10000 | 10000 |
1 km monthly SWIR1 reflectance | 1 km monthly SWIR1 reflectance (1230–1250 nm) | N/A | 16-bit signed integer | -1000 | N/A | 0 to 10000 | 10000 |
1 km monthly SWIR2 reflectance | 1 km monthly SWIR2 reflectance (1580–1640 nm) | N/A | 16-bit signed integer | -1000 | N/A | 0 to 10000 | 10000 |
1 km monthly SWIR3 reflectance | 1 km monthly SWIR3 reflectance (2225–2275 nm) | N/A | 16-bit signed integer | -1000 | N/A | 0 to 10000 | 10000 |
1 km monthly VI Quality | 1 km monthly VI Quality | Bit Field | 16-bit unsigned integer | 65535 | N/A | 0 to 65534 | N/A |
1 km monthly blue reflectance | 1 km monthly blue reflectance (478–498 nm) | N/A | 16-bit signed integer | -1000 | N/A | 0 to 10000 | 10000 |
1 km monthly green reflectance | 1 km monthly green reflectance (545–565 nm) | N/A | 16-bit signed integer | -1000 | N/A | 0 to 10000 | 10000 |
1 km monthly pixel reliability | 1 km monthly pixel reliability | Rank | 8-bit signed integer | -4, -1 | N/A | 0 to 11 | N/A |
1 km monthly red reflectance | 1 km monthly red reflectance (600–680 nm) | N/A | 16-bit signed integer | -1000 | N/A | 0 to 10000 | 10000 |
1 km monthly relative azimuth angle | 1 km monthly relative azimuth angle | Degree | 16-bit signed integer | -20000 | N/A | -18000 to 18000 | 100 |
1 km monthly sun zenith angle | 1 km monthly sun zenith angle | Degree | 16-bit signed integer | -20000 | N/A | 0 to 18000 | 100 |
1 km monthly view zenith angle | 1 km monthly view zenith angle | Degree | 16-bit signed integer | -20000 | N/A | 0 to 18000 | 100 |
All scale factors are to be divided.
Fill Value | Description |
---|---|
-15000 | over ocean/water |
-13000 | over land |
Fill Value | Description |
---|---|
-4 | over ocean/water |
-1 | over land |
Rank | Description |
---|---|
0 | Excellent |
1 | Good |
2 | Acceptable |
3 | Marginal |
4 | Pass |
5 | Questionable |
6 | Poor |
7 | Cloud Shadow |
8 | Snow/Ice |
9 | Cloud |
10 | Estimated |
11 | LTAVG |
Product Quality information can be found in the combined User Guide and Algorithm Theoretical Basis Document (ATBD). For the “500 m 16 days pixel reliability” SDS Layer, a rank quality table for each pixel can be found in Table 5. For the “500 m 16 days VI Quality” SDS Layer, for use with all VI’s, a bit field Quality Assurance table can be found in Table 13, with additional information available in Table 14. Accuracy Precision and Uncertainty information is available in Section 12.1.4.
The Quality Assessment (QA) layer is stored in an efficient bit-encoded manner. The unpack_sds_bits executable from the LDOPE Tools is available to the user community to help parse and interpret the quality layer.
Quality assurance information should be considered when determining the usability of data for a particular science application. The ArcGIS MODIS-VIIRS Python Toolbox contains tools capable of decoding quality data layers while producing thematic quality raster files for each quality attribute.
For additional information on product quality, refer to the VIIRS Land Product Quality website.
Due to missing critical inputs, this product lacks coverage for tiles h33v07 and h18v14, which are located over water.
For complete information about known issues please refer to the MODIS/VIIRS Land Quality Assessment website and the User Guide and ATBD.