SNAP pytohn api rayleigh correction help

development python
#1

hello ,

I want to to use SNAP python API using Rayleigh correction tools .but i takes errors.
First i need help how to define inputs parameters to use nappy.GPF.createProduct('RayleighCorrection', parameters, s) i don’t find some manual about this

here my code :

outfile_snappy='foldername'
s=ProductIO.readProduct('/folder_inp_name.SAFE')
HashMap = snappy.jpy.get_type('java.util.HashMap')
snappy.GPF.getDefaultInstance().getOperatorSpiRegistry().loadOperatorSpis()
parameters = HashMap()

parameters.put('ComputeRayleighopticalthicknessbands', True)
parameters.put('ComputebottomofRayleighreflecncebands', True)
parameters.put('ComputegaseousabsorptioncorrectedTOAreflectancebands', True)
parameters.put('ComputeTOAreflectancebands', True)
parameters.put('Addairmass', True)
parameters.put('imageresoluoninmintargetproduct.Resamplingisonlyifsourceproductisnotresampledyet(S2MSIonly)', '10')

parameters.put('SealevelpressureinhPa(S@MSIonly)', '1000')
parameters.put('OzoneinDU(SSIonly)', '300.0')
parameters.put('Sourcebands', 'B4')
target=snappy.GPF.createProduct('RayleighCorrection', parameters, s)
ProductIO.writeProduct(target, outfile_snappy, 'GeoTIFF')

and i take this error :

target=snappy.GPF.createProduct('RayleighCorrection', parameters, s)
RuntimeError: org.esa.snap.core.gpf.OperatorException: Please select at least one source band.

e.g. i want to use this for all bands .

thanks you

#2

Use: gpt RayleighCorrection -h

Snappy is less efficient than using gpt directly. You may want to use subprocess.run() from python if you are processing a list of files.

#4

yes i use this command and i take this help in select bands :

-PsourceBandNames=<string,string,string,...> The source bands for the computation.

but if i try to follow define this parametre :

parameters.put('PsourceBandNames', 'B01','B02','B03','B04','B05','B06','B07','B08','B09','B10','B11','B12')

i have this error :

parameters.put('sourceBandNames', 'B01','B02','B03','B04','B05','B06','B07','B08','B09','B10','B11','B12') RuntimeError: no matching Java method overloads found

any idea how to fix it ?

#5

I would try putting the list of source band names into a Python list:

parameters.put('sourceBandNames', ['B01', 'B02', 'B03','B04', 'B05', 'B06', 'B07', 'B08', 'B09','B10', 'B11', 'B12'])
#6

I tried this using python list but i take error : ValueError: cannot convert a Python 'list' to a Java 'java.lang.Object' , and if i use () like this ('B01','B02','B03','B04','B05','B06','B07','B08','B09','B10','B11','B12') i take error : ValueError: cannot convert a Python 'tuple' to a Java 'java.lang.Object'

#7

Hi, please use a single string containing the comma sperated band names.
‘B01,B02,B03,B04,B05,B06,B07,B08,B09,B10,B11,B12’

1 Like
#8

some error if i use ‘B01,B02,B03,B04,B05,B06,B07,B08,B09,B10,B11,B12’ :

RuntimeError: org.esa.snap.core.gpf.OperatorException: Please select at least one source band.

#9

Can you show us the full parameters.put(...) line?

#10

1st try :
parameters.put('PsourceBandNames','B01,B02,B03,B04,B05,B06,B07,B08,B09,B10,B11,B12')

error 1 :

target=snappy.GPF.createProduct('RayleighCorrection', parameters, s) RuntimeError: org.esa.snap.core.gpf.OperatorException: Please select at least one source band.

2st try :
parameters.put('PsourceBandNames', ['B01', 'B02', 'B03','B04', 'B05', 'B06', 'B07', 'B08', 'B09','B10', 'B11', 'B12'])

Error 2 :

ValueError: cannot convert a Python 'list' to a Java 'java.lang.Object

3st try :

parameters.put('PsourceBandNames', 'B01','B02','B03','B04','B05','B06','B07','B08','B09','B10','B11','B12')

error 3 :
ValueError: cannot convert a Python 'tuple' to a Java 'java.lang.Object'

4st try :
parameters.put('PsourceBandNames', 'B01', 'B02', 'B03','B04', 'B05', 'B06', 'B07', 'B08', 'B09','B10', 'B11', 'B12')

error 4 :

RuntimeError: no matching Java method overloads found

5st try :
parameters.put('PsourceBandNames','B01_B02_B03_B04_B05_B06_B07_B08_B09_B10_B11_B12')

error 5 :
RuntimeError: org.esa.snap.core.gpf.OperatorException: Please select at least one source band.

i will be use os commands to run RayleighCorrection if i have some option to define export path and name folder

#11

'PsourceBandNames' should be just 'sourceBandNames', which explains the error message. If you read the gpt help carefully you will see that -P<name> is used to indicate a setting for the <name> parameter. Another way to check for the way parameters are set is with the SNAP GUI Graph Builder tool – just save and view the .xml file for the graph.

#12

is the some errors is i use sourceBandNames.

1st
parameters.put('sourceBandNames','B01,B02,B03,B04,B05,B06,B07,B08,B09,B10,B11,B12')

error 1 :
target=snappy.GPF.createProduct('RayleighCorrection', parameters, s) RuntimeError: org.esa.snap.core.gpf.OperatorException: Operator 'RayleighCorrectionOp': Value for 'Source bands' is invalid: 'B01'

2st

parameters.put('sourceBandNames',['B01', 'B02', 'B03','B04', 'B05', 'B06', 'B07', 'B08', 'B09','B10', 'B11', 'B12'])

error 2 :

ValueError: cannot convert a Python 'list' to a Java 'java.lang.Object'

3st
parameters.put('sourceBandNames',('B01', 'B02', 'B03','B04', 'B05', 'B06', 'B07', 'B08', 'B09','B10', 'B11', 'B12'))

error 3:
parameters.put('sourceBandNames',('B01', 'B02', 'B03','B04', 'B05', 'B06', 'B07', 'B08', 'B09','B10', 'B11', 'B12')) ValueError: cannot convert a Python 'tuple' to a Java 'java.lang.Object'

4st
parameters.put('sourceBandNames','B01','B02','B03','B04','B05','B06','B07','B08','B09','B10','B11','B12')

error 4 :

`parameters.put('sourceBandNames','B01','B02','B03','B04','B05','B06','B07','B08','B09','B10','B11','B12')RuntimeError: no matching Java method overloads found`

5st
parameters.put('sourceBandNames','B01_B02_B03_B04_B05_B06_B07_B08_B09_B10_B11_B12')
error 5 :
RuntimeError: org.esa.snap.core.gpf.OperatorException: Operator 'RayleighCorrectionOp': Value for 'Source bands' is invalid: 'B01_B02_B03_B04_B05_B06_B07_B08_B09_B10_B11_B12'

#13

Have a look at %USERPROFILE%\.snap\snap-python\snappy\examples\snappy_bmaths.py. At the bottom of the file there is a note that future versions of snappy will use a Python dict object to set parameters.

I tried the example from the note – apparently the future has not yet arrived.