VIIRS Geolocation Product File Specifications for Image-resolution Bands
Version 2.0.9
November 30, 2018
This document describes the format and content of the NASA standard VIIRS geolocation product
(VNP03, VJ103), specifically for the image-resolution (I) bands. This specification is applicable
to VIIRS geolocation products derived from the Suomi National Polar-orbiting Satellite System (SNPP)
and Joint Polar-orbiting Satellite System-1 (JPSS-1/NOAA-20) missions; subsequently, it will extend
to cover other JPSS missions as well in the future. The product is stored as a Network Common Data
Form (netCDF) file for each VIIRS data granule. It contains:
Geodetic position (latitude, longitude, and height above geoid)for the center of each VIIRS
Earth View observation, according to World Geodetic System 1984 (WGS84) standard.
Sun and satellite ('sensor') bearings for each VIIRS Earth View observation.
EOS land/sea mask values for the center of each VIIRS Earth View observation.
Sun and Moon positions with respect to VIIRS for each scan.
Instrument parameter information sufficient to enable geolocation for specific bands and
sub-pixel ground location.
The specification is organized into four sections: Global Attributes;
Scan-Level Attributes; Geolocation Attributes; and Navigation Data. The metadata
are intended to satisfy two sets of requirements:
* Help users organize, ingest, catalog, and search data products
* Help users with their product documentation needs.
Global metadata attributes include core, product-specific, structural, and VIIRS-specific metadata.
The Scan-Level Attributes include scan-level metadata, spacecraft ephemeris, and spatial element
geolocation values.
The baseline netCDF implementation of this product is as follows: Granule metadata are stored in
individual netCDF attributes. The remaining file-level parameters are stored as netCDF scientific
data sets (SDS) with specified dimensions. Any exceptions to this baseline are noted for the individual
field. A few geolocation fields exist only in the Day-Night Band (DNB) version of the product. These
fields are appropriately listed separately at the end of that section.
The scan data are stored as SDSs. Multi-dimensional fields are stored with the scan dimension varying
least. Three categories of scan-level data exist: scan-level metadata, geolocation data, and navigation
data. The netCDF dimension names and nominal dimension lengths used for each category are listed in the
Global Attributes section. The geolocation fields are all defined as two-dimensional arrays with their
dimensions corresponding to the along-track and along-scan dimensions.
The array indexing is row-dominant, consistent with netCDF convention.
The example fields and their values listed below were extracted from an SNPP-VIIRS geolocation product.
Values for many fields are expected to change on a granule to granule basis.
1. Global Attributes
1.1 Dimensions
The following dimensions define the size of all the array fields in the SDSs:
Name Description Example
---- ----------- -------
number_of_scans The number of scans in the granule 202
number_of_lines The number of lines in the granule 6464
number_of_pixels The number of pixels per line 6400
vector_elements The number of spatial dimensions 3
quaternion_elements The number of values in the quaternions 4
1.2 Global Metadata
The data-type field listed below is relevant for I/O of these fields only, since each metadata set is
stored as a single text block. The supported data types include the following: string, double
(64-bit floating point number), float32 (32-bit floating point number), integer (32-bit integer),
ubyte (unsigned 8-bit integer), and short (16-bit integer).
Metadata Name Data Type Example
------------- -------- ---------
title string "VIIRS I-band Geolocation Data"
platform string "Suomi-NPP"
product_name string "VNP03IMG.A2018334.0654.001.2018334131826.nc"
LocalGranuleID string "VNP03IMG.A2018334.0654.001.2018334131826.nc"
LongName string "VIIRS/NPP Imagery Resolution Terrain Corrected Geolocation 6-Min L1 Swath 375m"
ShortName string "VNP03IMG"
processing_version string "v2.0.3"
Conventions string "CF-1.6"
institution string "NASA Goddard Space Flight Center, VIIRS L1 Processing Group" ;
license string "http://science.nasa.gov/earth-science/earth-science-data/data-information-policy/"
naming_authority string "gov.nasa.gsfc.VIIRSland"
date_created string "2018-11-30T08:18:26Z"
ProductionTime string "2018-11-30T08:18:26Z"
keywords_vocabulary string "NASA Global Change Master Directory (GCMD) Science Keywords"
stdname_vocabulary string "NetCDF Climate and Forecast (CF) Metadata Convention"
creator_name string "VIIRS L1 Processing Group"
creator_email string "modis-ops@lists.nasa.gov"
creator_url string "http://ladsweb.nascom.nasa.gov"
project string "VIIRS L1 Project"
publisher_name string "LAADS"
publisher_url string "http://ladsweb.nascom.nasa.gov"
publisher_email string "modis-ops@lists.nasa.gov"
processing_level string "GEO"
cdm_data_type string "swath"
number_of_filled_scans integer 202
OrbitNumber integer 36744
history string "geolocate_viirs.exe PGE501.1.AS5110.NPP_OPS.2018-334T06:54.NA.2018-334T13:18:24.4361511.pcf"
source string "VNP01.A2018334.0654.001.2018334131548.nc,VIIRS_NPP_CAL_STATIC_LUT_v2.0.0.26_20181025_vcst.nc,VIIRS_NPP_CAL_RSB_DYNAMIC_LUT_20120103_20181229_v2.0.0.26_20181025_vcst.nc,VIIRS_NPP_CAL_DNB_DYNAMIC_LUT_20120121_20190126_v2.0.0.26_20181025_vcst.nc,VIIRS_NPP_CAL_STRAYLIGHT_DYNAMIC_LUT_20120123_20190105_v2.0.0.26_20181025_vcst.nc,VIIRS_NPP_CMN_LUT_v2.0.0.26_20181025_vcst.nc,VIIRS_NPP_GEO_LUT_20130425152500_vcst.nc,off_USNO-PolarWander-UT1-ANC_Ser7_USNO_000f_20181130_201811300000Z_20181130000105Z_ee20181207120000Z_np.ascii"
time_coverage_start string "2018-11-30T06:54:00.000Z"
TAI93_leapseconds integer 10
time_coverage_end string "2018-11-30T07:00:00.000Z"
PGE_StartTime string "2018-11-30 06:54:00.000"
PGE_EndTime string "2018-11-30 07:00:00.000"
StartTime string "2018-11-30 06:54:00.000"
EndTime string "2018-11-30 07:00:00.000"
PGE_Name string "PGE501"
VersionId string "001"
startDirection string "Descending"
endDirection string "Descending"
DayNightFlag string "Night"
format_version integer 2
instrument_number integer 2
GRingPointSequenceNo integer[4] 1, 2, 3, 4
PGEVersion string "2.0.9"
GRingPointLatitude double[4] -56.3128, -49.24005, -30.56964, -35.64502
GRingPointLongitude double[4] -71.19838, -117.5293, -104.2118, -71.22906
geospatial_lat_units string "degrees_north"
geospatial_lon_units string "degrees_east"
geospatial_lat_min double -56.46531
geospatial_lat_max double -30.56964
geospatial_lon_min double -117.5293
geospatial_lon_max double -71.19838
SouthBoundingCoordinate double -56.46531
NorthBoundingCoordinate double -30.56964
WestBoundingCoordinate double -117.5293
EastBoundingCoordinate double -71.19838
AlgorithmVersion string "NPP_PR03_L1WG v2.0.3"
RangeBeginningTime string "06:54:00.000000"
AlgorithmType string "SCI"
RangeEndingTime string "07:00:00.000000"
ProcessingEnvironment string "Linux minion7127 3.10.0-862.14.4.el7.x86_64 #1 SMP Wed Sep 26 15:12:11 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux"
identifier_product_doi string "10.5067/VIIRS/VNP03IMG.001"
identifier_product_doi_authority string "http://dx.doi.org"
SatelliteInstrument string "NPP_OPS"
RangeBeginningDate string "2018-11-30"
RangeEndingDate string "2018-11-30"
InputPointer string "VNP01.A2018334.0654.001.2018334131548.nc,TLE-AUX_npp_20181130051605Z_20181129195100Z_ee00000000000000Z_-_c3s-_ops_all-_ops.txt,off_USNO-PolarWander-UT1-ANC_Ser7_USNO_000f_20181130_201811300000Z_20181130000105Z_ee20181207120000Z_np.ascii,VIIRS_NPP_CAL_STATIC_LUT_v2.0.0.26_20181025_vcst.nc,VIIRS_NPP_CMN_LUT_v2.0.0.26_20181025_vcst.nc,VIIRS_NPP_GEO_LUT_20130425152500_vcst.nc"
ProcessingCenter string "MODAPS-NASA"
2. Scan-level Data
SDS Name Description Format
-------- ------------- --------
scan_start_time Scan start-time in TAI93 seconds double(number_of_scans)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Scan start time (TAI93)"
units string "seconds"
_FillValue double -999.9
valid_min double 0.0
valid_max double 2000000000.0
scan_end_time Scan-ending time in TAI93 seconds double(number_of_scans)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Scan end time (TAI93)"
units string "seconds"
_FillValue double -999.9
valid_min double 0.0
valid_max double 2000000000.0
ev_mid_time Mid-time of the Earth viewing portion double(number_of_scans)
of each scan in TAI93 seconds
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Earth view mid time (TAI93)"
units string "seconds"
_FillValue double -999.9
valid_min double 0.0
valid_max double 2000000000.0
HAM_side Half-Angle Mirror side ubyte(number_of_scans)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Half-angle mirror side"
_FillValue ubyte 255
valid_min ubyte 0
valid_max ubyte 1
sensor_mode VIIRS sensor mode ubyte(number_of_scans)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Half-angle mirror side"
_FillValue ubyte 255
flag_values ubyte[7] 0, 1, 2, 3, 4, 5, 6
flag_meanings string "Launch Activation Outgas Diagnostic Day Night Safe"
scan_quality VIIRS Geolocation scan quality flags short(number_of_scans)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Geolocation scan quality flags"
_FillValue short -999
flag_masks short[15] 1, 2, 3, 4, 8, 12, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096
flag_meanings string "eaGap_small eaGap_medium eaGap_large HAMRTA_encoder_corrupt_fullScan HAMRTA_encoder_corrupt_partScan HAMRTA_encoder_missing_packets SAA solar_eclipse lunar_eclipse(DNB_only) spare(unused) SCE_Side_A_B SCE_side_invalid HAM_non-nominal_start Synch_loss Sector_rotation"
3. Geolocation Data
SDS Name Description Format
-------- ------------- --------
latitude Geodetic latitude float32(number_of_lines, number_of_pixels)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Latitudes of pixel locations"
units string "degrees_north"
_FillValue float32 -999.9
valid_min float32 -90.0
valid_max float32 90.0
longitude Geodetic longitude float32(number_of_lines, number_of_pixels)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Longitudes of pixel locations"
units string "degrees_east"
_FillValue float32 -999.9
valid_min float32 -180.0
valid_max float32 180.0
height Terrain height short(number_of_lines, number_of_pixels)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Terrain height at pixel locations"
units string "meters"
_FillValue short -32767
valid_min short -1000
valid_max short 10000
scale_factor float32 1.0
add_offset float32 0.0
range Range from satellite to pixel short(number_of_lines, number_of_pixels)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Satellite-to-pixel range"
units string "meters"
_FillValue short -32768
valid_min short 0
valid_max short 32767
scale_factor float32 100.0
add_offset float32 800000.0
sensor_azimuth Sensor azimuth angle short(number_of_lines, number_of_pixels)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Sensor azimuth angle at pixel locations"
units string "degrees"
_FillValue short -32768
valid_min short -18000
valid_max short 18000
scale_factor float32 0.01
add_offset float32 0.0
sensor_zenith Sensor zenith angle short(number_of_lines, number_of_pixels)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Sensor zenith angle at pixel locations"
units string "degrees"
_FillValue short -32768
valid_min short 0
valid_max short 18000
scale_factor float32 0.01
add_offset float32 0.0
solar_azimuth Solar azimuth angle short(number_of_lines, number_of_pixels)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Solar azimuth angle at pixel locations"
units string "degrees"
_FillValue short -32768
valid_min short -18000
valid_max short 18000
scale_factor float32 0.01
add_offset float32 0.0
solar_zenith Solar zenith angle short(number_of_lines, number_of_pixels)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Solar zenith angle at pixel locations"
units string "degrees"
_FillValue short -32768
valid_min short 0
valid_max short 18000
scale_factor float32 0.01
add_offset float32 0.0
land_water_mask Land/Water mask ubyte(number_of_lines, number_of_pixels)
long_name string "Land/Water mask at pixel locations"
_FillValue ubyte 255
flag_values ubyte[8] 0, 1, 2, 3, 4, 5, 6, 7
flag_meanings string "Shallow_Ocean Land Coastline Shallow_Inland Ephemeral Deep_Inland Continental Deep_Ocean"
quality_flag Pixel-level quality flags ubyte(number_of_lines, number_of_pixels)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Geolocation pixel quality flags"
flag_masks ubyte[4] 1, 2, 4, 8
flag_meanings string "Input_invalid Pointing_bad Terrain_bad SolarAngle_bad"
4. Navigation Data
SDS Name Description Format
-------- ------------- --------
att_quat_ev Attitude quaternion at mid-time float32
for the Earth view (number_of_scans, quaternion_elements)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Attitude quaternions at EV mid-times (J2000 to spacecraft)"
_FillValue float32 -999.9
valid_min float32 -1.0
valid_max float32 1.0
att_ang_start Attitude angles at start-time float32 (number_of_scans, vector_elements)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Attitude angles (roll, pitch, yaw) at EV start-times"
units string "degrees"
_FillValue float32 -999.9
valid_min float32 -180.0
valid_max float32 180.0
att_ang_end Attitude angles at end-time float32(number_of_scans, vector_elements)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Attitude angles (roll, pitch, yaw) at EV end-times"
units string "degrees"
_FillValue float32 -999.9
valid_min float32 -180.0
valid_max float32 180.0
att_ang_mid Attitude angles at mid-time float32(number_of_scans, vector_elements)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Attitude angles (roll, pitch, yaw) at EV mid-times"
units string "degrees"
_FillValue float32 -999.9
valid_min float32 -180.0
valid_max float32 180.0
orb_pos_ev_start Orbit position at scan-start float32(number_of_scans, vector_elements)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Orbit position vectors at EV start-times (ECR)"
units string "meters"
_FillValue float32 -9999999.0
valid_min float32 -7300000.0
valid_max float32 7300000.0
orb_pos_ev_end Orbit position at scan-end float32(number_of_scans, vector_elements)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Orbit position vectors at EV end-times (ECR)"
units string "meters"
_FillValue float32 -9999999.0
valid_min float32 -7300000.0
valid_max float32 7300000.0
orb_pos_ev_mid Orbit position at mid-scan float32(number_of_scans, vector_elements)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Orbit position vectors at EV mid-times (ECR)"
units string "meters"
_FillValue float32 -9999999.0
valid_min float32 -7300000.0
valid_max float32 7300000.0
orb_vel_ev_start Orbit velocity at scan-start float32(number_of_scans, vector_elements)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Orbit velocity vectors at EV start-times (ECR)"
units string "meters/second"
_FillValue float32 -9999999.0
valid_min float32 -7600.0
valid_max float32 7600.0
orb_vel_ev_end Orbit velocity at scan-end float32(number_of_scans, vector_elements)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Orbit velocity vectors at EV end-times (ECR)"
units string "meters/second"
_FillValue float32 -9999999.0
valid_min float32 -7600.0
valid_max float32 7600.0
orb_vel_ev_mid Orbit velocity at mid-scan float32(number_of_scans, vector_elements)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Orbit velocity vectors at EV mid-times (ECR)"
units string "meters/second"
_FillValue float32 -9999999.0
valid_min float32 -7600.0
valid_max float32 7600.0
solar_j2000 Solar vectors in J2000 frame float32 (number_of_scans, vector_elements)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Solar unit vectors in J2000 frame"
_FillValue float32 -999.9
valid_min float32 -1.0
valid_max float32 1.0
solar_inst Solar vectors in VIIRS frame float32(number_of_scans, vector_elements)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Solar unit vectors in VIIRS frame"
_FillValue float32 -999.9
valid_min float32 -1.0
valid_max float32 1.0
earth_sun_distance Earth to Sun distance float32(number_of_scans)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Earth-Sun distance"
units string "AU"
_FillValue float32 -999.9
valid_min float32 0.98
valid_max float32 1.02
lunar_j2000 Lunar vectors in J2000 frame float32(number_of_scans, vector_elements)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Lunar unit vectors in J2000 frame"
_FillValue float32 -999.9
valid_min float32 -1.0
valid_max float32 1.0
lunar_inst Lunar vectors in VIIRS frame float32(number_of_scans, vector_elements)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Lunar unit vectors in VIIRS frame"
_FillValue float32 -999.9
valid_min float32 -1.0
valid_max float32 1.0
earth_moon_distance Earth to Moon distance float32(number_of_scans)
SDS Attributes:
Attribute Name Format Example
-------------- ------ -------
long_name string "Earth-Moon distance"
units string "meters"
_FillValue float32 -999.9
valid_min float32 3.5e+08
valid_max float32 4.2e+08