GRASS GIS manual: i.modis.qc

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NAME

i.modis.qc - Extracts quality control parameters from Modis QC layers.

KEYWORDS

QC, Quality Control, surface reflectance, Modis

SYNOPSIS

i.modis.qc
i.modis.qc help
i.modis.qc input=name output=name productname=string qcname=string [band=string] [--overwrite] [--verbose] [--quiet]

Flags:

--overwrite: Allow output files to overwrite existing files
--verbose: Verbose module output
--quiet: Quiet module output

Parameters:

input=name: Name of input surface reflectance QC layer [bit array]
output=name: Name for output QC type classification layer
productname=string: Name of MODIS product type; Options: mod09Q1,mod09A1,mod09A1s,mod11A1,mod11A2; Default: mod09Q1; mod09Q1: surf. refl. 250m 8-days; mod09A1: surf. refl. 500m 8-days; mod09A1s: surf. refl. 500m 8-days, State QA; mod11A1: LST 1Km daily (Day/Night); mod11A2: LST 1Km 8-days (Day/Night)
qcname=string: Name of QC type to extract; Options: adjcorr,atcorr,cloud,data_quality,diff_orbit_from_500m,modland_qa_bits,mandatory_qa_11A1,data_quality_flag_11A1,emis_error_11A1,lst_error_11A1,data_quality_flag_11A2,emis_error_11A2,mandatory_qa_11A2,lst_error_11A2,aerosol_quantity,brdf_correction_performed,cirrus_detected,cloud_shadow,cloud_state,internal_clou_algorithm,internal_fire_algorithm,internal_snow_mask,land_water,mod35_snow_ice,pixel_adjacent_to_cloud; Default: modland_qa_bits; adjcorr: mod09: Adjacency Correction; atcorr: mod09: Atmospheric Correction; cloud: mod09: Cloud State; data_quality: mod09: Band-Wise Data Quality Flag; diff_orbit_from_500m: mod09: 250m Band is at Different Orbit than 500m; modland_qa_bits: mod09: MODIS Land General Quality Assessment; mandatory_qa_11A1: mod11A1: MODIS Land General Quality Assessment; data_quality_flag_11A1: mod11A1: Detailed Quality Indications; emis_error_11A1: mod11A1: Average Emissivity Error Classes; lst_error_11A1: mod11A1: Average LST Error Classes; data_quality_flag_11A2: mod11A2: Detailed Quality Indications; emis_error_11A2: mod11A2: Average Emissivity Error Classes; mandatory_qa_11A2: mod11A2: MODIS Land General Quality Assessment; lst_error_11A2: mod11A2: Average LST Error Classes; aerosol_quantity: mod09A1s: StateQA Internal Snow Mask; brdf_correction_performed: mod09A1s: StateQA Internal Snow Mask; cirrus_detected: mod09A1s: StateQA Internal Snow Mask; cloud_shadow: mod09A1s: StateQA Internal Snow Mask; cloud_state: mod09A1s: StateQA Internal Snow Mask; internal_clou_algorithm: mod09A1s: StateQA Internal Snow Mask; internal_fire_algorithm: mod09A1s: StateQA Internal Snow Mask; internal_snow_mask: mod09A1s: StateQA Internal Snow Mask; land_water: mod09A1s: StateQA Internal Snow Mask; mod35_snow_ice: mod09A1s: StateQA Internal Snow Mask; pixel_adjacent_to_cloud: mod09A1s: StateQA Internal Snow Mask
band=string: Band number of Modis product (mod09Q1=[1,2],mod09A1=[1-7]); Options: 1,2,3,4,5,6,7; 1: mod09Q1/A1 Band 1: Red; 2: mod09Q1/A1 Band 2: NIR; 3: mod09A1 Band 3: Blue; 4: mod09A1 Band 4: Green; 5: mod09A1 Band 5: SWIR 1; 6: mod09A1 Band 6: SWIR 2; 7: mod09A1 Band 7: SWIR 3

DESCRIPTION

i.modis.qc Extracts Requested Quality Assessment flags from the following MODIS products: MOD09A1, MOD09Q1, and MOD11A2. This does include MOD09A1 QA_state_500m layer (see Notes).

MOD09A1/Q1: MODLAND QA Bits. bits=[0-1]

[00]= class 0: Corrected product produced at ideal quality -- all bands
[01]= class 1: Corrected product produced at less than ideal quality -- some or all bands
[10]= class 2: Corrected product NOT produced due to cloud effect -- all bands
[11]= class 3: Corrected product NOT produced due to other reasons -- some or all bands maybe be fill value (Note that a value of [11] overrides a value of [01])

MOD09Q1: Cloud State. bits=[2-3]

[00]= class 0: Clear -- No clouds
[01]= class 1: Cloudy
[10]= class 2: Mixed
[11]= class 3: Not Set ; Assumed Clear

MOD09Q1: Band-wise Data Quality 250m bits=[4-7][8-11]
MOD09A1: Band-wise Data Quality 500m bits=[2-5][6-9][10-13][14-17][18-21][22-25][26-29]

[0000]= class 0: highest quality
[0111]= class 1: noisy detector
[1000]= class 2: dead detector; data interpolated in L1B
[1001]= class 3: solar zenith ge 86 degrees
[1010]= class 4: solar zenith ge 85 and lt 86 degrees
[1011]= class 5: missing input
[1100]= class 6: internal constant used in place of climatological data for at least one atmospheric constant
[1101]= class 7: correction out of bounds, pixel constrained to extreme allowable value
[1110]= class 8: L1B data faulty
[1111]= class 9: not processed due to deep ocean or cloud
Class 10-15: Combination of bits unused

MOD09A1/Q1: Atmospheric correction bit=[12]/[30]

[0]= class 0: Not Corrected product
[1]= class 1: Corrected product

MOD09A1/Q1: Adjacency correction bit=[13]/[31]

[0]= class 0: Not Corrected product
[1]= class 1: Corrected product

MOD09Q1: Different orbit from 500m product, bit=[14]

[0]= class 0: same orbit as 500m
[1]= class 1: different orbit from 500m

MOD11A2: Mandatory QA Flags bits=[0-1]

[00]= class 0: LST produced, good quality, not necessary to examine more detailed QA
[01]= class 1: LST produced, other quality, recommend examination of more detailed QA
[10]= class 2: LST not produced due to cloud effects
[11]= class 3: LST not produced primarily due to reasons other than cloud

MOD11A1: Data Quality Flag bits=[2-3]

[00]= class 0: Good data quality of L1B in bands 31 and 32
[01]= class 1: Other quality data
[10]= class 2: TBD
[11]= class 3: TBD

MOD11A1: Emis Error Flag bits=[4-5]

[00]= class 0: Average emissivity error le 0.01
[01]= class 1: Average emissivity error le 0.02
[10]= class 2: Average emissivity error le 0.04
[11]= class 3: Average emissivity error gt 0.04

MOD11A1: LST Error Flag bits=[6-7]

[00]= class 0: Average LST error le 1
[01]= class 1: Average LST error le 2
[10]= class 2: Average LST error le 3
[11]= class 3: Average LST error gt 3


MOD11A2: Mandatory QA Flags bits=[0-1]

[00]= class 0: LST produced, good quality, not necessary to examine more detailed QA
[01]= class 1: LST produced, other quality, recommend examination of more detailed QA
[10]= class 2: LST not produced due to cloud effects
[11]= class 3: LST not produced primarily due to reasons other than cloud

MOD11A2: Data Quality Flag bits=[2-3]

[00]= class 0: Good data quality of L1B in 7 TIR bands
[01]= class 1: Other quality data
[10]= class 2: TBD
[11]= class 3: TBD

MOD11A2: Emis Error Flag bits=[4-5]

[00]= class 0: Average emissivity error le 0.01
[01]= class 1: Average emissivity error le 0.02
[10]= class 2: Average emissivity error le 0.04
[11]= class 3: Average emissivity error gt 0.04

MOD11A2: LST Error Flag bits=[6-7]

[00]= class 0: Average LST error le 1
[01]= class 1: Average LST error le 2
[10]= class 2: Average LST error le 3
[11]= class 3: Average LST error gt 3

MOD09A1s: Cloud State bits=[0-1]

[00]= class 0: clear
[01]= class 1: cloudy
[10]= class 2: mixed
[11]= class 3: not set, assumed clear

MOD09A1s: Cloud shadow bits=[2]

[0]= class 0: yes
[1]= class 1: no

MOD09A1s: Land/Water Flag bits=[3-5]

[000]= class 0: Shallow ocean
[001]= class 1: Land
[010]= class 2: Ocean coastlines and lake shorelines
[011]= class 3: Shallow inland water
[100]= class 4: Ephemeral water
[101]= class 5: Deep inland water
[110]= class 6: Continental/moderate ocean
[111]= class 7: Deep ocean

MOD09A1s: Aerosol Quantity bits=[6-7]

[00]= class 0: Climatology
[01]= class 1: Low
[10]= class 2: Average
[11]= class 3: High

MOD09A1s: Cirrus detected bits=[8-9]

[00]= class 0: None
[01]= class 1: Small
[10]= class 2: Average
[11]= class 3: High

MOD09A1s: Internal Cloud Algorithm Flag bits=[10]

[0]= class 0: Cloud
[1]= class 1: No cloud

MOD09A1s: Internal Fire Algorithm Flag bits=[11]

[0]= class 0: Fire
[1]= class 1: No fire

MOD09A1s: MOD35 snow/ice flag bits=[12]

[0]= class 0: Yes
[1]= class 1: No

MOD09A1s: Pixel adjacent to cloud bits=[13]

[0]= class 0: Yes
[1]= class 1: No

MOD09A1s: BRDF correction performed bits=[14]

[0]= class 0: Yes
[1]= class 1: No

MOD09A1s: Internal Snow Mask bits=[15]

[0]= class 0: Snow
[1]= class 1: No snow

NOTES

In MOD09A1: It seems that cloud related info is not filled properly in the standard QC (MOD09A1 in this module) since version 3, State-QA 500m images (MOD09A1s in this module) should be used (see Vermote et al., 2008).

TODO

Add one Day products.

REFERENCES

MODIS Products
Vermote E.F., Kotchenova S.Y., Ray J.P. MODIS Surface Reflectance User's Guide. Version 1.2. June 2008. MODIS Land Surface Reflectance Science Computing Facility. Homepage

AUTHOR

Yann Chemin

Last changed: $Date: 2013-01-22 22:18:02 -0800 (Tue, 22 Jan 2013) $

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