HDF-EOS V2 MODIS L2G-lite Land Snow Cover File Specification
Revision 1.0 (12/21/2015)
Product ID(s): MOD10 L2G 1DY 500M (MOD10GA)
Description:
The MODIS 500m Resolution Level 2G (L2G) Daily Snow Cover
file contains the restructured Level 2 (L2) Snow Fraction data
(observations) which intersects a geographic area, a tile, in the MODIS Land
global Level 3 (L3) grid. The global L3 grid is divided into a number of
tiles, areas with a nominal size of 1100 km by 1100 km (10 deg. by 10 deg.).
The data is stored at a nominal grid resolutions of 500m.
A single 500m (L2) MOD10_L2 snow cover observation consist of the NDSI Snow Cover,
and the general and bit level QA flags. The observation coverage, which is obtained
from the MODPTHKM files gives an estimate of the intersection between the observation
and the grid cell (relative to the observation area).
The 500m observations are chosen in the following three steps:
1. First, one 500m observation in each orbit for each grid cell is selected by
selecting the one with the largest observation coverage.
2. Next, for a 500m grid cell, the 500m observations with the maximum
observation coverage for each orbit are selected and sorted in the order of
ascending orbit numbers (earliest first).
3. The first layer is then selected using the same compositing criteria as have
been used in the MODIS collection 5 version of MOD10A1, using a scoring function
depending on the local noon, distance from nadir and observation coverage.
The observation with the highest score is pulled up to the first layer and stored.
The observation coverage is stored with each observation so the end-user can
always reorder the observations using whatever criteria they want, once they
read them in. The final output also has a orbit and granule pointer layer which
taken with the orbit and granule archive metadata array, can
show the relevant orbits and granules that forms the part of the first and all
subsequent layers. Snow albedo is also calculated for all cells that are mapped
as snow covered.
This new format reduces the number of 500m L2G files from five files to
one file per day for each tile. The mapping between the original L2G files and
this new L2G file is:
MOD10_L2 - all SDSs
MODPTHKM - only the obscov and the granulepnt
There are two ways to which the observation data can be stored in a L2G
grid file, full and compact. The actual method is specified by the
L2GStorageFormat metadata values. In both methods,
the first layer of observations is stored in a 2 dimensional array. In the
full method, all of the values are stored in a 3 dimensional array with the
slowest varying dimension specifying the observation layer. This is an
inefficient storage method because typically a large number of cells are empty.
For the compact method, the additional observation values are stored in a single
dimensional array, with the dimension corresponding to the number of
additional observations since the beginning of the file. Essentially, the
additional observations are run-length encoded with each observation stored
sequentially for each cell.
In addition, the a run-time parameter may specify that only the first layer
be stored, in which case the additional arrays are not stored.
Points of Contact:
Robert Wolfe
NASA's Goddard Space Flight Center, Code 614.5
Greenbelt, MD 20771
(301) 614-5508
robert.e.wolfe@nasa.gov
Principal Investigator:
Eric Vermote
University of Maryland, College Park
NASA's Goddard Space Flight Center, Code 614.5
Greenbelt, MD 20771
(301) 405-8052
vermote@kratmos.gsfc.nasa.gov
===========================================================================
Generic Constructs
ECS Metadata Strings:
Notes: "FR" is an abbreviation for "FREE_RANGE".
"D/T" is an abbreviation for "DATE/TIME"
(A) implies that multiple values are stored within a
single array.
A value of "Variable" indicates that this value will vary
according to the granule being processed.
"M" means class M.
CoreMetadata.0
This string will contain the following PVL fields:
# of
Field Name Data Value Value
Type s
GROUP = INVENTORYMETADATA
GROUP = CollectionDescriptionClass
SHORTNAME STRING 1 "MOD10GA"
VERSIONID STRING 1 Variable
END_GROUP = CollectionDescriptionClass
GROUP = ECSDataGranule
REPROCESSINGPLANNED STRING 1 "further update
is anticipated"
REPROCESSINGACTUAL STRING 1 "reprocessed"
LOCALGRANULEID STRING 1 Variable
DAYNIGHTFLAG STRING 1 Variable
PRODUCTIONDATETIME D/T 1 Variable
LOCALVERSIONID STRING 1 Variable
SIZEMBECSDATAGRANULE DOUBLE 1 Variable
END_GROUP = ECSDataGranule
GROUP = PGEVersionClass
PGEVERSION STRING 1 Variable
END_GROUP = PGEVersionClass
GROUP = InputGranule
INPUTPOINTER STRING FR (A) Variable
END_GROUP = InputGranule
GROUP = RangeDateTime
RANGEBEGINNINGDATE DATE 1 Variable
RANGEBEGINNINGTIME TIME 1 Variable
RANGEENDINGDATE DATE 1 Variable
RANGEENDINGTIME TIME 1 Variable
END_GROUP = RangeDateTime
GROUP = GRing
EXCLUSIONGRINGFLAG STRING 1 "N"
END_GROUP = GRing
GROUP = GRingPoint
GRINGPOINTLATITUDE DOUBLE 4 (A) Variable
GRINGPOINTLONGITUDE DOUBLE 4 (A) Variable
GRINGPOINTSEQUENCENO INTEGER 4 (A) Variable
END_GROUP = GRingPoint
GROUP = ZoneIdentifierClass
ZONEIDENTIFIER STRING 1 "0"
END_GROUP = ZoneIdentifierClass
GROUP = OrbitCalculatedSpatialDomain
** number of containers is equal to "NumberofOrbits" **
ORBITNUMBER INTEGER 1 Variable
EQUATORCROSSINGLONGITUDE DOUBLE 1 Variable
EQUATORCROSSINGDATE DATE 1 Variable
EQUATORCROSSINGTIME TIME 1 Variable
END_GROUP = OrbitCalculatedSpatialDomain
GROUP = MeasuredParameter
PARAMETERNAME STRING FR (A) "MOD09G"
GROUP = QAFLAGS
AUTOMATICQUALITYFLAG STRING 1 Variable
AUTOMATICQUALITYFLAGEXPLANATION
STRING 1 Variable
SCIENCEQUALITYFLAG STRING 1 Variable
SCIENCEQUALITYFLAGEXPLANATION
STRING 1 Variable
END_GROUP = QAFlags
GROUP = QAStats
QAPERCENTMISSINGDATA INTEGER 1 Variable
QAPERCENTOUTOFBOUNDSDATA INTEGER 1 Variable
QAPERCENTINTERPOLATEDDATA INTEGER 1 Variable
END_GROUP = QAStats
END_GROUP = MeasuredParameter
GROUP = AssociatedPlatformInstrumentSensor
ASSOCIATEDPLATFORMSHORTNAME STRING 1 "Terra/Aqua"
ASSOCIATEDINSTRUMENTSHORTNAME STRING 1 "MODIS"
ASSOCIATEDSENSORSHORTNAME STRING 1 "MODIS"
END_GROUP = AssociatedPlatformInstrumentSensor
GROUP = AdditionalAttributes
ADDITIONALATTRIBUTENAME STRING FR (A) Variable
PARAMETERVALUE STRING FR (A) Variable
ADDITIONALATTRIBUTENAME.5 = "HORIZONTALTILENUMBER"
ADDITIONALATTRIBUTENAME.6 = "VERTICALTILENUMBER"
ADDITIONALATTRIBUTENAME.7 = "TileID"
ADDITIONALATTRIBUTENAME.8 = "PROCESSVERSION"
ADDITIONALATTRIBUTENAME.9 = "identifier_product_doi"
ADDITIONALATTRIBUTENAME.10 = "identifier_product_doi_authority"
END_GROUP = AdditionalAttributes
END_GROUP = INVENTORYMETADATA
ArchiveMetadata.0
This string will contain the following PVL fields:
# of
Field Name Data Value Value
Type s
GROUP = ARCHIVEMETADATA
GROUP = BoundingRectangle
WESTBOUNDINGCOORDINATE DOUBLE 1 Variable
NORTHBOUNDINGCOORDINATE DOUBLE 1 Variable
EASTBOUNDINGCOORDINATE DOUBLE 1 Variable
SOUTHBOUNDINGCOORDINATE DOUBLE 1 Variable
END_GROUP = BoundingRectangle
GEOANYABNORMAL STRING 1 Variable
GEOESTMAXRMSERROR DOUBLE 1 Variable
LONGNAME STRING 1 "MODIS/Terra Snow Product Daily L2G Global 500m SIN Grid Day"
SPSOPARAMETERS STRING 1 "2015"
PROCESSINGCENTER STRING 1 "MODAPS"
NUMBEROFOVERLAPGRANULES INTEGER 1 Variable
NUMBEROFINPUTGRANULES INTEGER 1 Variable
NUMBEROFGRANULES INTEGER 1 Variable
GRANULENUMBERARRAY INTEGER FR(A) Variable
GRANULEPOINTERARRAY INTEGER FR(A) Variable
ORBITNUMBERARRAY INTEGER FR(A) Variable
NUMBEROFORBITS INTEGER 1 Variable
GRANULEBEGINNINGDATETIME STRING "NumberofGranules"
Variable
GRANULEENDINGDATETIME STRING "NumberofGranules"
Variable
GRANULEDAYNIGHTFLAG STRING "NumberofGranules"
Variable
GRANULEDAYOFYEAR INTEGER "NumberofGranules"
Variable
GRANULEBEGINNINGDATETIMEARRAY STRING FR(A) Variable
GRANULEENDINGDATETIMEARRAY STRING FR(A) Variable
GRANULEDAYNIGHTFLAGARRAY STRING FR(A) Variable
NADIRDATARESOLUTION STRING 1 Variable
CHARACTERISTICBINANGULARSIZE DOUBLE 1 Variable
CHARACTERISTICBINSIZE DOUBLE 1 Variable
DATACOLUMNS INTEGER 1 Variable
DATAROWS INTEGER 1 Variable
GLOBALGRIDCOLUMNS INTEGER 1 Variable
GLOBALGRIDROWS INTEGER 1 Variable
MAXIMUMOBSERVATIONS INTEGER 1 Variable
ADDITIONALLAYERS INTEGER 1 Variable
TOTALOBSERVATIONS INTEGER 1 Variable
TOTALADDITIONALOBSERVATIONS INTEGER 1 Variable
COVERAGECALCULATIONMETHOD STRING 1 Variable
FIRSTLAYERSELECTIONCRITERIA STRING 1 Variable
L2GSTORAGEFORMAT STRING 1 Variable
PROCESSINGENVIRONMENT STRING 1 Variable
DESCRREVISION STRING 1 Variable
SYSTEMFILENAME STRING FR (A) Variable
PERCENTPROCESSED INTEGER 1 Variable
PERCENTLAND INTEGER 1 Variable
PERCENTLANDSEAMASKCLASS INTEGER 8 Variable
RANKING STRING 1 Variable
KEEPALL STRING 1 Variable
COVERAGEMINIMUM DOUBLE 1 Variable
MAXOUTPUTRES STRING 1 Variable
DEEPOCEANFLAG STRING 1 Variable
CLOUDOPTION STRING 1 Variable
******************************************************************
* 1. The field "L2GStorageFormat"
* is either "full", "compact" or "one layer only".
* 2. The field "CoverageCalculationMethod" is either
* "area" or "volume".
* 3. The field "FirstLayerSelectionCriteria" is either
* "nearest neighbor" or "maximum observation coverage".
******************************************************************
END_GROUP = ARCHIVEMETADATA
StructuralMetadata.0
This string will be populated automatically by HDF-EOS.
Grid Structure: MODIS_Grid_2D
Dimensions:
Dimension Name Value
YDim:MODIS_Grid_2D "DataRows"
XDim:MODIS_Grid_2D "DataColumns"
Corner Locations:
Corner Values
UpperLeftPointMtrs (Variable, Variable)
LowerRightPointMtrs (Variable, Variable)
Geographic Grid Projection Parameters:
Supported Grids: Integerized Sinusoidal (GCTP_ISINUS)
Sinusoidal (GCTP_SNSOID)
Interrupted Goodes Homolosine (GCTP_GOOD)
Lambert Azimuthal Equal Area (GCTP_LAMAZ)
Projection gridID = GCTP_ISINUS
ProjParam[0] 6371007.181
ProjParam[1 to 7] 0.0
ProjParam[8] 86400
ProjParam[9] 0.0
ProjParam[10] 1.0
ProjParam[11 to 12] 0.0
Spherecode -1
GridOrigin HDFE_GD_UL
Projection gridID = GCTP_SNSOID
ProjParam[0] 6371007.181
ProjParam[1 to 12] 0.0
Spherecode -1
GridOrigin HDFE_GD_UL
Projection gridID = GCTP_GOOD
ProjParam[0 to 12] 0.0
Spherecode 19
GridOrigin HDFE_GD_UL
Projection gridID = GCTP_LAMAZ
ProjParam[0] 6371228.0
ProjParam[1 to 5] 0.0
ProjParam[6] Variable
ProjParam[7 to 12] 0.0
Spherecode 19
GridOrigin HDFE_GD_UL
Grid Structure: MODIS_Grid_3D
Dimensions:
Dimension Name Value
Additional Layers:MODIS_Grid_3D "AdditionalLayers"
YDim:MODIS_Grid_3D "DataRows"
XDim:MODIS_Grid_3D "DataColumns"
Corner Locations: (same as MODIS_Grid_2D)
Geographic Grid Projection Parameters: (same as MODIS_Grid_2D)
===========================================================================
Additional global attributes:
Data
Name Type
maximum_observations_500m INT8
total_additional_observations_500m INT32
l2g_storage_format_500m STRING
NumberLandWater1km INT32
identifier_product_doi STRING
identifier_product_doi_authority STRING
===========================================================================
DataFields:
The following datafields are always in this file:
num_observations
NDSI_Snow_Cover_1
NDSI_Snow_Cover_Basic_QA_1
NDSI_Snow_Cover_Algorithm_Flags_QA_1
NDSI_1
SnowAlbedo_1
obscov_1
orbit_pnt_1
granule_pnt_1
If the "L2GStorageFormat" metadata value is "full", the following
datafields are also present:
NDSI_Snow_Cover_f
NDSI_Snow_Cover_Basic_QA_f
NDSI_Snow_Cover_Algorithm_Flags_QA_f
NDSI_f
SnowAlbedo_f
obscov_f
orbit_pnt_f
granule_pnt_f
If the "L2GStorageFormat" metadata value is "compact", the following
datafields are also present:
NDSI_Snow_Cover_c
NDSI_Snow_Cover_Basic_QA_c
NDSI_Snow_Cover_Algorithm_Flags_QA_c
NDSI_c
SnowAlbedo_c
obscov_c
orbit_pnt_c
granule_pnt_c
nadd_obs_row
Each datafield has at least the following 4 attributes:
long_name (STRING)
units (STRING)
valid_range (agrees with data type of SDS)
_FillValue (agrees with data type of SDS)
Some datafields also contain the following 5 attributes:
add_offset (float64)
add_offset_err (float64)
calibrated_nt (int32)
scale_factor (float64)
scale_factor_err (float64)
Nadir Data Resolution (STRING - "500m")
Key (STRING)
===========================================================================
Name Data Dimensions
Type
num_observations INT8 "YDim:MODIS_Grid_2D",
"XDim:MODIS_Grid_2D"
Description:
The number of 500m observations per pixel contained within
this L2G file. In addition, if the value is less than zero,
it means that intersections were not computed for this cell.
If it is -1, it is part of the fill region of the grid. If it
is -2, it is in the area identified as 'non-production' in the
Land Production Mask.
HDF Attributes:
Number of
Values or
Max.
Attribute Data String Value
Type Length
long_name STRING 22 "Number of observations"
units STRING 4 "none"
valid_range INT8 2 0, 127
_FillValue INT8 1 -1
===========================================================================
Name Data Dimensions
Type
NDSI_Snow_Cover_1 UINT8 "YDim:MODIS_Grid_2D",
"XDim:MODIS_Grid_2D"
NDSI_Snow_Cover_f UINT8 "Additional Layers:MODIS_Grid_3D",
"YDim:MODIS_Grid_3D",
"XDim:MODIS_Grid_3D"
NDSI_Snow_Cover_c UINT8 "TotalAdditionalObservations"
metadata value
Description:
500m NDSI Snow Cover
"NDSI_Snow_Cover_1" is for storing the first layer of observations
and is always stored.
"NDSI_Snow_Cover_f" and "NDSI_Snow_Cover_c" are for storing the
additional layers of observations. "NDSI_Snow_Cover_f" is for the
full format and is stored only if "L2GStorageFormat" is "full".
"NDSI_Snow_Cover_c" is for the compact format and is stored only if
"L2GStorageFormat" is "compact".
Number of
Values or
Max.
Attribute Data String Value
Type Length
long_name STRING 29 Variable
units STRING 4 "none"
valid_range UINT8 2 0, 100
_FillValue UINT8 1 255
Nadir Data Resolution
STRING 5 "500 m"
Key STRING 135 "0-100=ndsi snow, 200=missing data, 201=no decision, 211=night, 237=inland water, 239=ocean, 250=cloud, 254=detector saturated, 255=fill"
Note: The attribute "long_name" is
"NDSI_snow_cover - first layer" for "NDSI_Snow_Cover_1",
"NDSI_snow_cover - additional layers, full"
for "NDSI_Snow_Cover_f", or
"NDSI_snow_cover - additional layers, compact"
for "NDSI_Snow_Cover_c".
===========================================================================
Name Data Dimensions
Type
NDSI_Snow_Cover_Basic_QA_1 UINT8 "YDim:MODIS_Grid_2D",
"XDim:MODIS_Grid_2D"
NDSI_Snow_Cover_Basic_QA_f UINT8 "Additional Layers:MODIS_Grid_3D",
"YDim:MODIS_Grid_3D",
"XDim:MODIS_Grid_3D"
NDSI_Snow_Cover_Basic_QA_c UINT8 "TotalAdditionalObservations"
metadata value
Description:
500m NDSI snow cover general quality values
"NDSI_Snow_Cover_Basic_QA_1" is for storing the first layer of observations
and is always stored.
"NDSI_Snow_Cover_Basic_QA_f" and "NDSI_Snow_Cover_Basic_QA_c" are for storing the
additional layers of observations. "NDSI_Snow_Cover_Basic_QA_f" is for the
full format and is stored only if "L2GStorageFormat" is "full".
"NDSI_Snow_Cover_Basic_QA_c" is for the compact format and is stored only if
"L2GStorageFormat" is "compact".
Number of
Values or
Max.
Attribute Data String Value
Type Length
long_name STRING 51 Variable
valid_range UINT8 2 0, 4
_FillValue UINT8 1 255
Key STRING 111 "0=best, 1=good, 2=ok, 3=poor, 4=other-not used, 211=night, 239=ocean, 255=unusable L1B data or no data"
Note: The attribute "long_name" is
"NDSI snow cover general quality value - first layer" for "NDSI_Snow_Cover_Basic_QA_1",
"NDSI snow cover general quality value - additional layers, full"
for "NDSI_Snow_Cover_Basic_QA_f", or
"NDSI snow cover general quality value - additional layers, compact"
for "NDSI_Snow_Cover_Basic_QA_c".
===========================================================================
Name Data Dimensions
Type
NDSI_Snow_Cover_Algorithm_Flags_QA_1 UINT8 "YDim:MODIS_Grid_2D",
"XDim:MODIS_Grid_2D"
NDSI_Snow_Cover_Algorithm_Flags_QA_f UINT8 "Additional Layers:MODIS_Grid_3D",
"YDim:MODIS_Grid_3D",
"XDim:MODIS_Grid_3D"
NDSI_Snow_Cover_Algorithm_Flags_QA_c UINT8 "TotalAdditionalObservations"
metadata value
Description:
500m NDSI snow cover bit level quality flags
"NDSI_Snow_Cover_Algorithm_Flags_QA_1" is for storing the first layer of observations
and is always stored.
"NDSI_Snow_Cover_Algorithm_Flags_QA_f" and "NDSI_Snow_Cover_Algorithm_Flags_QA_c" are for storing the
additional layers of observations. "NDSI_Snow_Cover_Algorithm_Flags_QA_f" is for the
full format and is stored only if "L2GStorageFormat" is "full".
"NDSI_Snow_Cover_Algorithm_Flags_QA_c" is for the compact format and is stored only if
"L2GStorageFormat" is "compact".
Number of
Values or
Max.
Attribute Data String Value
Type Length
long_name STRING 45 Variable
units STRING 4 "none"
valid_range UINT8 2 0, 254
_FillValue UINT8 1 255
Key STRING 908 "bit on means:
bit 0: inland water flag
bit 1: low visible screen failed, reversed snow detection
bit 2: low NDSI screen failed, reversed snow detection
bit 3: combined temperature and height screen failed, snow reversed because too warm and too low
This screen is also used to flag a high elevation too warm snow detection,
in this case the snow detection is not changed but this bit is set.
bit 4: too high swir screen and applied at two thresholds:
QA bit flag set if band6 TOA > 25% & band6 TOA <= 45%,
indicative of unusual snow conditon, or snow commission error;
snow detection reversed if band6 TOA > 45%
bit 5: spare
bit 6: spare
bit 7: solar zenith screen, indicates increased uncertainty in results"
Note: The attribute "long_name" is
"NDSI Snow Cover Algorithm Flags - first layer" for "NDSI_Snow_Cover_Algorithm_Flags_QA_1",
"NDSI Snow Cover Algorithm Flags - additional layers, full"
for "NDSI_Snow_Cover_Algorithm_Flags_QA_f", or
"NDSI Snow Cover Algorithm Flags - additional layers, compact"
for "NDSI_Snow_Cover_Algorithm_Flags_QA_c".
===========================================================================
Name Data Dimensions
Type
NDSI_1 1NT16 "YDim:MODIS_Grid_2D",
"XDim:MODIS_Grid_2D"
NDSI_f 1NT16 "Additional Layers:MODIS_Grid_3D",
"YDim:MODIS_Grid_3D",
"XDim:MODIS_Grid_3D"
NDSI_c 1NT16 "TotalAdditionalObservations"
metadata value
Description:
500m Raw NDSI layer
"NDSI_1" is for storing the first layer of observations
and is always stored.
"NDSI_f" and "NDSI_c" are for storing the
additional layers of observations. "NDSI_f" is for the
full format and is stored only if "L2GStorageFormat" is "full".
"NDSI_c" is for the compact format and is stored only if
"L2GStorageFormat" is "compact".
Number of
Values or
Max.
Attribute Data String Value
Type Length
long_name STRING 22 Variable
units STRING 4 "none"
valid_range INT16 2 0, 10000
_FillValue INT16 1 0
scale_factor FLOAT32 1 1.0E-4
Note: The attribute "long_name" is
"Raw NDSI - first layer" for "NDSI_1",
"Raw NDSI - additional layers, full"
for "NDSI_f", or
"Raw NDSI - additional layers, compact"
for "NDSI_c".
===========================================================================
Name Data Dimensions
Type
SnowAlbedo_1 UINT8 "YDim:MODIS_Grid_2D",
"XDim:MODIS_Grid_2D"
SnowAlbedo_f UINT8 "Additional Layers:MODIS_Grid_3D",
"YDim:MODIS_Grid_3D",
"XDim:MODIS_Grid_3D"
SnowAlbedo_c UINT8 "TotalAdditionalObservations"
metadata value
Description:
500m Snow albedo over areas with valid snow cover
"SnowAlbedo_1" is for storing the first layer of observations
and is always stored.
"SnowAlbedo_f" and "SnowAlbedo_c" are for storing the
additional layers of observations. "SnowAlbedo_f" is for the
full format and is stored only if "L2GStorageFormat" is "full".
"SnowAlbedo_c" is for the compact format and is stored only if
"L2GStorageFormat" is "compact".
Number of
Values or
Max.
Attribute Data String Value
Type Length
long_name STRING 69 Variable
units STRING 4 "none"
valid_range UINT8 2 0, 100
_FillValue UINT8 1 255
Key STRING 222 "0-100=snow albedo, 101=no_decision, 111=night, 125=land, 137=inland water, 139=ocean, 150=cloud, 151=cloud detected as snow, 250=missing, 251=self_shadowing, 252=landmask mismatch, 253=BRDF_failure, 254=non-production_mask"
Note: The attribute "long_name" is
"Snow albedo of the corresponding snow cover observation - first layer" for "SnowAlbedo_1",
"Snow albedo of the corresponding snow cover observation - additional layers, full"
for "SnowAlbedo_f", or
"Snow albedo of the corresponding snow cover observation - additional layers, compact"
for "SnowAlbedo_c".
===========================================================================
Name Data Dimensions
Type
obscov_1 INT8 "YDim:MODIS_Grid_2D",
"XDim:MODIS_Grid_2D"
obscov_f INT8 "Additional Layers:MODIS_Grid_3D",
"YDim:MODIS_Grid_3D",
"XDim:MODIS_Grid_3D"
obscov_c INT8 "TotalAdditionalObservations"
metadata value
Description:
Observation coverage is an estimate of the amount of intersection
between observation footprint and grid cell.
"obscov_1" is for storing the first layer of observations
and is always stored.
"obscov_f" and "obscov_c" are for storing the
additional layers of observations. "obscov_f" is for the
full format and is stored only if "L2GStorageFormat" is "full".
"obscov_c" is for the compact format and is stored only if
"L2GStorageFormat" is "compact".
HDF Attributes:
Number of
Values or
Max.
Attribute Data String Value
Type Length
long_name STRING 34 Variable
units STRING 7 "percent"
valid_range INT8 2 0, 100
_FillValue INT8 1 -1
add_offset FLOAT64 1 0.0
add_offset_err FLOAT64 1 0.0
calibrated_nt INT32 1 5
scale_factor FLOAT64 1 0.01
scale_factor_err FLOAT64 1 0.0
Note: The attribute "long_name" is
"Observation coverage - first layer" for "obscov_1",
"Observation coverage - additional layers, full" for "obscov_f", or
"Observation coverage - additional layers, compact" for "obscov_c".
===========================================================================
Name Data Dimensions
Type
orbit_pnt_1 INT8 "YDim:MODIS_Grid_2D",
"XDim:MODIS_Grid_2D"
orbit_pnt_f INT8 "Additional Layers:MODIS_Grid_3D",
"YDim:MODIS_Grid_3D",
"XDim:MODIS_Grid_3D"
orbit_pnt_c INT8 "TotalAdditionalObservations"
metadata value
Description:
Pointer to the orbit information for each 500m observation. This value
is zero relative, with zero (0) refering to the first orbit in the
"OrbitCalculatedSpatialDomain" HDF EOS inventory metadata group.
"orbit_pnt_1" is for storing the first layer of observations
and is always stored.
"orbit_pnt_f" and "orbit_pnt_c" are for storing the
additional layers of observations. "orbit_pnt_f" is for the
full format and is stored only if "L2GStorageFormat" is "full".
"orbit_pnt_c" is for the compact format and is stored only if
"L2GStorageFormat" is "compact".
HDF Attributes:
Number of
Values or
Max.
Attribute Data String Value
Type Length
long_name STRING 27 Variable
units STRING 4 "none"
valid_range INT8 2 0, 15
_FillValue INT8 1 -1
Note: The attribute "long_name" is
"Orbit pointer - first layer" for "orbit_pnt_1",
"Orbit pointer - additional layers, full" for "orbit_pnt_f", or
"Orbit pointer - additional layers, compact" for "orbit_pnt_c".
===========================================================================
Name Data Dimensions
Type
granule_pnt_1 UINT8 "YDim:MODIS_Grid_2D",
"XDim:MODIS_Grid_2D"
granule_pnt_f UINT8 "Additional Layers:MODIS_Grid_3D",
"YDim:MODIS_Grid_3D",
"XDim:MODIS_Grid_3D"
granule_pnt_c UINT8 "TotalAdditionalObservations"
metadata value
Description:
Pointer to the granule information for each 500m observation. This value
is zero relative, with zero (0) refering to the first overlap granule in the
"GranulePointerArray" HDF EOS ArchiveMetadata group.
"granule_pnt_1" is for storing the first layer of observations
and is always stored.
"granule_pnt_f" and "granule_pnt_c" are for storing the
additional layers of observations. "orbit_pnt_f" is for the
full format and is stored only if "L2GStorageFormat" is "full".
"orbit_pnt_c" is for the compact format and is stored only if
"L2GStorageFormat" is "compact".
HDF Attributes:
Number of
Values or
Max.
Attribute Data String Value
Type Length
long_name STRING 29 Variable
units STRING 4 "none"
valid_range UINT8 2 0, 254
_FillValue UINT8 1 255
Note: The attribute "long_name" is
"Granule pointer - first layer" for "granule_pnt_1",
"Granule pointer - additional layers, full" for "granule_pnt_f", or
"Granule pointer - additional layers, compact" for "granule_pnt_c".
===========================================================================
Name Data Dimensions
Type
nadd_obs_row INT32 "DataRows" metadata value
Description:
The number of additional observations in each row in the
compact storage form of the L2G grid.
This field is only stored if "L2GStorageFormat" is "compact".
HDF Attributes:
Number of
Values or
Max.
Attribute Data String Value
Type Length
long_name STRING 41 "Number of additional observations
per row"
units STRING 4 "none"
valid_range INT32 2 0, INT32_MAX
_FillValue INT32 1 -1
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