Import MODIS |

### Import MODIS Product

#### Implementation of the MODIS Product Reader

This implementation supports a subset of the products available of the NASA sensor MODIS, both on the Aqua and Terra platform. These products can be imported into the SNAP, used as input products in the scientific data processors (where applicable) and accessed by Java developers using the Java product I/O framework.

#### Supported MODIS Data Products

The following MODIS data product types are supported by SNAP:

Product Type | Content | Description
--- | --- | ---
`MOD021KM` `MYD021KM` | MODIS/Terra/Aqua Calibrated Radiances 5-Min L1B Swath 1 km | This Level 1B product contains calibrated and geolocated radiances at-aperture for all 36 MODIS spectral bands at 1km resolution.
`MOD02HKM` `MYD02HKM` | MODIS/Terra/Aqua Calibrated Radiances 5-Min L1B Swath 500 m | This Level 1B product contains calibrated and geolocated radiances at-aperture for MODIS spectral bands 1 through 7 at 500m resolution.
`MOD02QKM` `MYD02QKM` | MODIS/Terra/Aqua Calibrated Radiances 5-Min L1B Swath 250 m | This Level 1B product contains calibrated and geolocated radiances at-aperture for MODIS spectral bands 1 and 2 at 250m resolution.
`MODOCL2` `MYDOCL2` | MODIS/Terra/Aqua Ocean Color Radiance Products 5-Min L2 Swath 1 km Day | The MODIS Level 2 Ocean Color water leaving radiance product, MxDOCL2, contains normalized water-leaving radiance for 7 of the 36 wavelengths/spectral bands (Band 8 through 14, 412 through 618nm) of MODIS which are used to derive nearly all the ocean products, ocean aerosol properties and clear water epsilons (parameters numbers 1-12). This Level 2 data collection has daily coverage with a 1-km resolution at nadir.
`MODOCL2A` `MYDOCL2A` | MODIS/Terra/Aqua Ocean Color Derived Products Group 1 5-Min L2 Swath 1 km Day | This MODIS Level 2 Ocean Color Derived Products Group 1, MxDOCL2A, product contains the following ocean products: chlorophyll derived from several different algorithms, phycobilin pigment concentrations, chlorophyll fluorescence, suspended solids concentration, coccolith, calcite, coccolith corrected pigment concentration and ocean water attenuation (ocean parameter number 13-25). This Level 2 product has daily coverage with a l-km resolution at nadir.
`MODOCL2B` `MYDOCL2B` | MODIS/Terra/Aqua Ocean Color Derived Products Group 2 5-Min L2 Swath 1 km Day | This MODIS Level 2 Ocean Color Derived Products Group 2, MxDOCL2B, product contains the following ocean products: chlorophyll_a pigment concentration for Case 2 waters using 2 and 3 band algorithms, photosynthetic available radiation (PAR) and absorbed radiation by phytoplankton (ARP), organic matter concentration, total absorption at 5 wavebands, chlorophyll and gelbstoff absorption coefficients. (ocean parameter number 26-36). This Level 2 product has daily coverage with a 1-km resolution at nadir.
`MODOCQC` `MYDOCQC` | MODIS/Terra/Aqua Ocean Color Quality Control Product | This MODIS Level 2 Ocean Color product contains quality control data.
`MOD28L2` `MYD28L2` | MODIS/Terra/Aqua Sea Surface Temperature Products 5-Min L2 Swath 1 km | This MODIS Level 2 Sea Surface Temperature Product,MxD28L2, product provides a long wavelength (11-12um, SST) sea surface temperature and a short wavelength sea surface temperature (3-4um, SST4) at 1-km resolution over the global oceans. Day and night retrievals are provided as separate products for both SST and SST4.
`MOD13A2` `MYD13A2` | MODIS/Terra/Aqua Vegetation Indices 16-Day L3 Global 1km | Global MODIS vegetation indices are designed to provide consistent spatial and temporal comparisons of vegetation conditions. Blue, red, and near-infrared reflectances, centered at 469-nanometers, 645-nanometers, and 858-nanometers, respectively, are used to determine the MODIS daily vegetation indices. The MODIS Normalized Difference Vegetation Index (NDVI) complements NOAA's Advanced Very High Resolution Radiometer (AVHRR) NDVI products and provides continuity for time series historical applications. MODIS also includes a new 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.
`MOD15A2` `MYD15A2` | MODIS/Terra/Aqua Leaf Area Index - Fraction of Photosynthetically Active Radiation 8-Day L4 Global 1km | The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 1-kilometer resolution on a Sinusoidal grid. Science Data Sets provided in the MOD15A2 include LAI, FPAR, a quality rating, and standard deviation for each variable. The LAI variable defines the number of equivalent layers of leaves relative to a unit of ground area, whereas FPAR measures the proportion of available radiation in the photosynthetically active wavelengths that are absorbed by a canopy. Both variables are used as satellite-derived parameters for calculating surface photosynthesis, evapotranspiration, and net primary production, which in turn are used to calculate terrestrial energy, carbon, water cycle processes, and biogeochemistry of vegetation.
`MOD09GA` `MYD09GA` | MODIS/Terra/Aqua Surface Reflectance Daily L2G Global 1km and 500m | The MODIS Surface Reflectance products provide an estimate of the surface spectral reflectance as it would be measured at ground level in the absence of atmospheric scattering or absorption. Low-level data are corrected for atmospheric gases and aerosols, yielding a level-2 basis for several higher-order gridded level-2 (L2G) and level-3 products. MOD09GA provides Bands 1-7 in a daily gridded L2G product in the Sinusoidal projection, including 500-meter reflectance values and 1-kilometer observation and geolocation statistics. 500-m Science Data Sets provided for this product include reflectance for Bands 1-7, a quality rating, observation coverage, observation number, and 250-m scan information. 1-kilometer Science Data Sets provided include number of observations, quality state, sensor angles, solar angles, geolocation flags, and orbit pointers.

#### MODIS Level 2 Products

The supported MODIS Level 2 products do not contain geo-location information. Instead, this information is stored in an accompanying quality control file (`MxDOCQC`). The SNAP software tries to locate this file in the same directory as the Level 2 product resides. If the geo-location file is not present, the Level 2 product will be opened as raw datasets without geo-coding.

#### MODIS Quality Flags

The current version does not support flag coding of MODIS products and therefore bitmask overlays are currently not possible.