Issue with resampled angular values (Sentinel2)

Hello,
I’m starting to get used of your very nice snappy from python.
Willing to get the viewing and solar angles values for each pixel I resample the S2 product. However, I cannot access the actual data afterward. Below is a example of my issue:
test_for_step_forum.py (1.1 KB)

import sys
import numpy as np
from snappy import ProductIO
from snappy import GPF

dir = ‘/DATA/Satellite/SENTINEL2/venice/L1C/’
file=dir+‘S2A_OPER_PRD_MSIL1C_PDMC_20160718T175711_R022_V20160718T101028_20160718T101028.SAFE/’

native product

product = ProductIO.readProduct(file)

sza=product.getBand(‘sun_zenith’)

width=sza.getRasterWidth()
szas2 = np.zeros(width, dtype=np.float32)
sza.readPixels(0, 0, width, 1, szas2)
print szas2

resampled product

GPF.getDefaultInstance().getOperatorSpiRegistry().loadOperatorSpis()

HashMap = jpy.get_type(‘java.util.HashMap’)
BandDescriptor = jpy.get_type(‘org.esa.snap.core.gpf.common.BandMathsOp$BandDescriptor’)

parameters = HashMap()
parameters.put(‘targetResolution’,60)
parameters.put(‘upsampling’,‘Bicubic’)
parameters.put(‘downsampling’,‘Mean’)
parameters.put(‘flagDownsampling’,‘FlagMedianAnd’)
parameters.put(‘resampleOnPyramidLevels’,True)

product=GPF.createProduct(‘Resample’, parameters, product)

sza=product.getBand(‘sun_zenith’)

width=sza.getRasterWidth()
szas2 = np.zeros(width, dtype=np.float32)
sza.readPixels(0, 0, width, 1, szas2)
print szas2

#which gives me
[ 28.1189003 28.09429932 28.06959915 28.04509926 28.02050018
27.99600029 27.97159958 27.94720078 27.92280006 27.89850044 27.8743
27.85009956 27.82589912 27.80179977 27.77770042 27.75370026
27.72970009 27.70569992 27.68180084 27.65800095 27.63419914
27.61050034]
[ nan nan nan …, nan nan nan]

Any idea to overcome this problem?
Thanks,
Tristan

Hello Tristan,

depending on the interpolation method, they are needed some pixels around the output pixel to carry out the interpolation. Because of this, in bilinear and bicubic methods, it is normal to obtain Nan in the borders of the output image.

Thanks a lot for your reply.
The “Nan” border is pretty large due to the very coarse resolution for the viewing geometry info. So loosing pixels is the price to pay to get proper angular information.
By the way, any news on the refinement of the azimuth angles data: