Changing the CRS in Snappy

s1tbx
#1

Good evening everybody,

I am using the Range-Doppler Terrain Correction in Snappy and since I would like to look at tif data all around the world in the program I guess I would need to change the Coordinate Reference System to the specific area (I thought it could do that automatically with the standard parameter but that does not seem to be the case). How would I add that parameter (EPSG/UTM Zone) to the code? My code currently:

def terrain_correction(product_subset, band= “Intensity_VH”):
parameters = HashMap()
parameters.put(‘demName’, ‘SRTM 1Sec HGT’)
parameters.put(‘pixelSpacingInMeter’, 10.0)
parameters.put(‘sourceBands’, band)
parameters.put(‘nodataValueAtSea’, “False”)
product_subset_corrected = GPF.createProduct(“Terrain-Correction”, parameters,
product_subset)
return product_subset_corrected

Thank you for your time.

#2

please try
parameters.put('mapProjection', "AUTO:42001")

This will select the UTM zone which is most suitable for each image.

#3

That worked, thank you!

Could I do the same with another map projection?
For example, how would I use the plate carree projection with snappy?

Thank you for your time.

#4

maybe @marpet knows this.

#5

To define the map projection you can enter the EPSG code. But for looking up I usually use EPSG.io or Spatial Reference.

You can use the GUI to find out what you can specify. Try Raster / Reprojection or Radar / Geometric / Terrain Correctino / Range Doppler Terrain Correction
most of the boxes and lists are searchable. Just start typing
You can use the EPSG code, or the WKT after you have defined the projection.

For plate caree you can type EPSG:32662

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image898×691 37.1 KB

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image710×762 28.5 KB

1 Like
#6

Thank you for the informative answer.

Could I use the EPSG:32662 for the complete globe or would I have to use different codes depending on if I am looking at for example the US or europe?

#7

The code is globally valid