I’m relatively new to sentinl-hub and i’m trying to get acess to sentinel1 images.
My goal is to get sentinel-1 image with the VV and VH bands in db (decibels) values.
I have manage to retrieve image using the following script but there are few things I don’t understand:
-
what are the units of that image? I have seen in the documentry that there are
BETA0
,SIGMA0_ELLIPSOID
orGAMMA0_ELLIPSOID
but i’m not sure how can I define which one I want in the python API. -
From how I understand the script, what I gonna get is VV, 2VH, VV/VH /100 and dataMask. Is there any way to get only the VV and VH? without the 2VH ot the vv/vh?
-
relate to question no. 2: why do you provide those bands (2 * VH ) ect. and not the VV and VH directly?
-
is there any way to get it already in decibels?
-
When I put large time interval, which image am I going to see? the first one? mosaic? mean value?
-
It says that the Orthorectification correction is an optional correction that applied on the image. how can I make sure that this was applied on the image I retrieved?
this is how I manage to retrieve the image:
evalscript = """
//VERSION=3
return [VV, 2 * VH, VV / VH / 100.0, dataMask]
"""
time_interval = '2019-07-06', '2020-07-07'
request = SentinelHubRequest(
evalscript=evalscript,
input_data=[
SentinelHubRequest.input_data(
data_collection=DataCollection.SENTINEL1_IW_DES,
time_interval=time_interval,
)
],
responses=[
SentinelHubRequest.output_response('default', MimeType.PNG)
],
bbox=bbox,
config=config
)
image = request.get_data()[0]
plot_image(image, factor=3.5/255, clip_range=(0,1))