ChangeDetectionTool

Microwave Toolbox
1

I have a series of SAR water body binary maps from the same area which I need to compare (spatial-temporal analysis, change detection). I am wondering whether SNAP offers any tools for SAR change detection? I couldn’t have found any!

Thanks
PS- This is SNAP installed on my PC. Does it include both Sentinel 1 and 2 tools?

SNAP.JPG1916×107 34.6 KB

2

Hi SAR2016

SNAP have in SAR Applications, Change Detection.

If you downloaded Sentinel Toolboxes, you should be have SNAP for Sentinel 1, 2 and 3!

Regards

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3

The attached shows the Sentinel Toolbox which I have installed.

SNAP.JPG1916×107 34.6 KB

When I use radar>FeatureExtraction>ChangeDetection, it only allows me to select “one source band” although we need at least two bands. That’s why I get this error.

What is the solution for that?
Thanks

4

I had the same question

http://forum.step.esa.int/t/change-detection-and-ratio/1727/12?u=gabrielaquintana77

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5

You can to know the version and which STBX you use in Help— About SNAP

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6

My version is SNAP 3. When I click on update, it shows this::unamused:

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7

Thanks! Now it’s working! I have co-registered the Water Mask Binary Maps extracted from SAR imagery. The radar change detection accepts only 2 bands (already co-registered).

thanks again

8

Just a quick question:

Is there any statistical analysis option for radar change detection? In order to understand how many areas have been changed,…

Thanks

9

Yes, through threshold based on mean and standard deviation value, you could to get segmentation of areas changed

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10

Are you talking about the Mask Upper/Lower Thresholds in change detection tool?
My two water masks are binary maps (extracted from SAR) with the value of 1 (water) and 0 (non-water). By default, it shows -2 and 2 as the figure shows. I did not get it exactly where these numbers are coming from! Should I change it?

Thanks.

11

I talks of thresholds after to calculate Log Ratio Band, but I don’t believe that this apply for binary maps. :flushed:

Please if I am wrong, someone correct me!!!

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12

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.:innocent:

13

Of course, radar if is the correct choice for water binary masks, please, check out this link

http://www.un-spider.org/advisory-support/recommended-practices/recommended-practice-flood-mapping/step-by-step

I don’t know is how to validate the mask! :disappointed_relieved:

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14

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.

15

One question

The ratio_change band no apply for that you want???

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16

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.

17

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).

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18

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.

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19

I am trying to update it, but this is the message I get.:neutral_face:

20

I’ve increased the priority of the existing issue.
I try to implement this the next week.

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