## 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.

## SEE ALSO

i.vi

## 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: 2013-01-23 07:18:02 +0100 (st, 23 I 2013) $

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