I talks of thresholds after to calculate Log Ratio Band, but I don’t believe that this apply for binary maps. 
Please if I am wrong, someone correct me!!!
1 Like
Yeah, I don’t know whether radar change detection is a right choice for Water binary masks obtained from SAR (It still contains the SAR metadata info. though).
Besides it, do you recommend some other tools to get the job done.
Of course, radar if is the correct choice for water binary masks, please, check out this link
I don’t know is how to validate the mask! 
1 Like
Thanks! I’ve seen this before. It’s good for water thresholding which I did. I just wanted to find out to what extent the water areas have been changed in time. That’s why I wanted to try the radar Change Detection.
One question
The ratio_change band no apply for that you want???
1 Like
This is what I am doing to get it done:
First, coregister two mask images, then use band math (subtraction, ref-slave). I do not use the change detection since I am not sure about threshold mask values given.
The current version of SNAP is 5.0, please update.
@lveci @marpet this is a recurring issue, users of older versions of SNAP do not receive messages to update to the latest one (or they receive that message only once).
1 Like
Users can see if new updates are available in the tools plugins window. Maybe we could also add “A new version is available” in the about box or on the top window title. Having the notification window come up every time SNAP is started may be too annoying for users that don’t want to update just yet.
1 Like
I am trying to update it, but this is the message I get.
http://step.esa.int/main/download/To get the latest version you need to download it again from the webpage.
1 Like
Thanks for the time and assistance. Since the update doesnot work for now, I assume that I should reinstall it. If so, I would rather wait till the issue is fixed for updating. 
The updating will not work, you will have to install 5.0 (and preferably uninstall 3.0). The issue that is discussed is related to how users of old versions are notified that a new major release exists.
1 Like
What is the working principle of change detection from SAR application?
How it detects the changed areas?
Is it based on difference in backscatter or anything else.
Thanks in advance
Is there any range of threshold value that is taken for performing the change detection?
no, the threshold is identified statistically.
Can you please help me get an idea about the statistical process by which we can decide the threshold.
the process from the Change Detection Tool is documented in the linked paper above.
You can find your own threshold by investigating the pixel values of water and non-water, for example using the histogram or statistics tool.
Ok sir.
Thank you