Alos palsar 2

Hi all
I just wanted to share with all this processing flow in SNAP with ALOS PALSAR 2. All help or advice is welcome!

  1. Download the product (HH and HV polarizations)

  2. Geometric / Collocation

  1. Convert both images (HH and HV) to DB

  2. Create a new band dividing HH by HV

  3. Apply a speckle filter

On the other hand, I use the HV decibels band (created on the step 3.) to make a forest/non forest mask, but the limit (according to the histogram) is around -47 or -48 decibels.

Thanks in advance for your suggestions!!

Thank you for sharing, this looks nice.

Just one comment: You probably missed to add the 32 as a constant in the equation. This would probably result in the expected valid range of values (-40 to +10)
Source: Calibration Result of ALOS-2/PALSAR-2 JAXA Standard Products

Thank you so mucha Andreas
The equation I’ve introduced in Band Math is this:

I didn’t know that was necessary a constant of 32…
So the expression would be?:
(10*Log10 (DN2) - 83 dB) +32

Hm, the documentation you showed is quite clear about it, you’re right. The unexpected range just reminded me of t this additional constant, but it applies to Level1.1 data only.

So it would make sense from a mathematical point of view, but not from the theory side…

As always, thank you Andreas

I have written to the ALOS PALSAR 2 support:

I will keep you updated!

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