On May 12, 4:35 pm, kishore1...@[EMAIL PROTECTED]
wrote:
>
> Hi,
> Thanks for your suggestions, I modified according your suggestions.
> Pl. go through my program
> pro vfm_feature_flags1,val
FUNCTION VFM_FEATURE_FLAGS1, Input
>
> ; this routine demonstrates how to read and extract values from a
> feature
> ; classification flag 16-bit integer value in CALIPSO Level 2
> Vertical
> ; Feature Mask files
> ;
> ; INPUT:
> ; val - the feature classification flag value to be decoded
> ;
> ; OUTPUT:
> ; all information is printed into the IDL log window
; Make sure input is usable
IF Input GT 65535L OR Input LT -32767L THEN $
MESSAGE, 'Input not a 16-bit flag.'
; Convert input to 16-bit value
Val = UINT(Input)
> print, val
>
> feature_type = 0
> feature_type_qa = 0
> ice_water_phase = 0
> ice_water_phase_qa = 0
> feature_subtype = 0
> cloud_aerosol_psc_type_qa = 0
> horizontal_averaging = 0
>
> Output = { feature_type:"", $
> feature_type_qa:"", $
> ice_water_phase:"", $
> ice_water_phase_qa:"", $
> feature_subtype:"", $
> cloud_aerosol_psc_type_qa:"", $
> horizontal_averaging:""}
>
> for i=0,15 do begin
> if ((val and 2L^i) NE 0) then begin
> print,'Bit set: ',i+1
> case i+1 of
> 1 : feature_type = feature_type + 1
> 2 : feature_type = feature_type + 2
> 3 : feature_type = feature_type + 4
> 4 : feature_type_qa = feature_type_qa + 1
> 5 : feature_type_qa = feature_type_qa + 2
> 6 : ice_water_phase = ice_water_phase + 1
> 7 : ice_water_phase = ice_water_phase + 2
> 8 : ice_water_phase_qa = ice_water_phase_qa + 1
> 9 : ice_water_phase_qa = ice_water_phase_qa + 2
> 10 : feature_subtype = feature_subtype + 1
> 11 : feature_subtype = feature_subtype + 2
> 12 : feature_subtype = feature_subtype + 4
> 13 : cloud_aerosol_psc_type_qa = cloud_aerosol_psc_type_qa + 1
> 14 : horizontal_averaging = horizontal_averaging + 1
> 15 : horizontal_averaging = horizontal_averaging + 2
> 16: horizontal_averaging = horizontal_averaging + 4
> else:
> endcase
> endif
> endfor
>
> case feature_type of
> 0 : Output.Feature_Type = 'invalid (bad or missing data)'
> 1 : Output.Feature_Type = 'clear air"
> 2 : begin
> Output.Feature_Type = 'cloud'
> case feature_subtype of
> 0 : Output.Feature_Subtype = 'low overcast, transparent'
> 1 : Output.Feature_Subtype = 'low overcast, opaque'
> 2 : Output.Feature_Subtype = 'transition strato***ulus'
> 3 : Output.Feature_Subtype = 'low, broken ***ulus'
> 4 : Output.Feature_Subtype = 'alto***ulus (transparent)'
> 5 : Output.Feature_Subtype = 'altostratus (opaque)'
> 6 : Output.Feature_Subtype = 'cirrus (transparent)'
> 7 : Output.Feature_Subtype = 'deep convective (opaque)'
> else : Output,'*** error getting Feature Subtype'
ELSE : Output.Feature_Subtype = '*** error getting Feature Subtype'
> endcase
> end
> 3 : begin
> Output.Feature_Type = 'aerosol'
> case feature_subtype of
> 0 : Output.Feature_Subtype = 'not determined'
> 1 : Output.Feature_Subtype = 'clean marine'
> 2 : Output.Feature_Subtype = 'dust'
> 3 : Output.Feature_Subtype = 'polluted continental'
> 4 : Output.Feature_Subtype = 'clean continental'
> 5 : Output.Feature_Subtype = 'polluted dust'
> 6 : Output.Feature_Subtype = 'smoke'
> 7 : Output.Feature_Subtype = 'other"
> else : Output,'*** error getting Feature Subtype'
ELSE : Output.Feature_Subtype = '*** error getting Feature Subtype'
> endcase
> end
> 4 : begin
> Output.Feature_Type = 'stratospheric feature--PSC or
> stratospheric aerosol'
> case feature_subtype of
> 0 : Output.Feature_Subtype = 'not determined'
> 1 : Output.Feature_Subtype = 'non-depolarizing PSC'
> 2 : Output.Feature_Subtype = 'depolarizing PSC'
> 3 : Output.Feature_Subtype = 'non-depolarizing aerosol'
> 4 : Output.Feature_Subtype = 'depolarizing aerosol'
> 5 : Output.Feature_Subtype = 'spare'
> 6 : Output.Feature_Subtype = 'spare'
> 7 : Output.Feature_Subtype = 'other'
> else : Output,'*** error getting Feature Subtype'
ELSE : Output.Feature_Subtype = '*** error getting Feature Subtype'
> endcase
> end
> 5 : Output.Feature_Type = 'surface'
> 6 : Output.Feature_Type = 'subsurface'
> 7 : Output.Feature_Type = 'no signal (totally attenuated)'
> else : Output,'*** error getting Feature Type'
ELSE : Output.Feature_Type = '*** error getting Feature Type'
> endcase
>
> case feature_type_qa of
> 0 : Output.Feature_Type_QA = 'none'
> 1 : Output.Feature_Type_QA = 'low'
> 2 : Output.Feature_Type_QA = 'medium'
> 3 : Output.Feature_Type_QA = 'high'
> else : Output,'*** error getting Feature Type QA'
ELSE : Output.Feature_Type_QA = '*** error getting Feature Type QA'
> endcase
>
> case ice_water_phase of
> 0 : Output.Ice_Water_Phase = 'unknown/not determined'
> 1 : Output.Ice_Water_Phase = 'ice'
> 2 : Output.Ice_Water_Phase = 'water'
> 3 : Output.Ice_Water_Phase = 'mixed phase'
> else : Output,'*** error getting Ice/Water Phase'
ELSE : Output.Ice_Water_Phase = '*** error getting Ice/Water Phase'
> endcase
>
> case ice_water_phase_qa of
> 0 : Output.Ice_Water_Phase_QA = 'none'
> 1 : Output.Ice_Water_Phase_QA = 'low'
> 2 : Output.Ice_Water_Phase_QA = 'medium'
> 3 : Output.Ice_Water_Phase_QA = 'high'
> else : Output,'*** error getting Ice/Water Phase QA'
ELSE : Output.Ice_Water_Phase_QA = '*** error getting Ice/Water Phase
QA'
> endcase
>
> if (cloud_aerosol_psc_type_qa eq 0) then begin
> Output.Cloud_Aerosol_PSC_Type_QA = 'not confident'
> endif else begin
> Output.Cloud_Aerosol_PSC_Type_QA = 'confident'
> endelse
>
> case horizontal_averaging of
> 0 : Output.Horizontal_averaging = 'not applicable'
> 1 : Output.Horizontal_averaging = '1/3 km'
> 2 : Output.Horizontal_averaging = '1 km'
> 3 : Output.Horizontal_averaging = '5 km'
> 4 : Output.Horizontal_averaging = '20 km'
> 5 : Output.Horizontal_averaging = '80 km'
> else : Output,'*** error getting Horizontal averaging'
ELSE : Output.Ice_Water_Phase = '*** error getting Ice/Water Phase'
> endcase
> help,Output,/structure
> ;Return, Output
RETURN, Output
> end
> Using above routine I wrote a small progam
> data1=[44474, 36282, 28602, 28090]
>
> for i=0,3 do begin
> ;vfm_feature_flags,data1(i)
> vfm_feature_flags1,data1(i)
> pause='' & read,pause
>
> endfor
> end
>
> Only, problem is how to recall output parameters.
Replace this very first line:
pro vfm_feature_flags,val
with
function vfm_feature_flags,val
then, down at the very end of the programme, remove the comment-out
from this line
;Return, Output
IDL has two types of programmes, 'procedures' and 'functions'.
Functions will return an output. Procedures can only alter input
parameters (although this can be used to effectively give output too).
Functions are called slightly differently to procedures, though the
code language in them is identical apart from the 'Return, A_Value'
thing.
To call the function, use:
result = vfm_feature_flags(value)
e.g.
myoutput = vfm_feature_flags(36282u)
Then you can look at the content of the output like this:
help, myoutput, /structure
or something like this:
print, myoutput.feature_type
to get a single output field from the structure.
Regards,
Chris
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