ESA Echoes in Space - Hazard: Flood mapping with Sentinel-1

[@kevalan1042]

Covered here: Subset, Multilook, Calibration, Terrain Correction, Create Stack, Layer Manager (overlay/transparency), RGB composite image, KMZ export (Google Earth).

[@tuyeimokamanya5910]

Wow. Thank you so much for this video. You are such a good teacher, I finally understand some concepts concerning this type of study. How you explained everything was simply meticulous. 😊😊😊😊

[@kuntheanuon8723]

Now, it was successful. Thanks for your sharing video about Flood mapping.

[@t0rs7en]

thank you very much. it helps me a lot to analyze the flood areas of the flood event of July 2021 in Germany

[@yahampathmarambe8879]

which polarization is good for flood mapping? is there any preference?

[@zainabkhan2475]

Please explain a bit on how phase polarity and entropy affects the identification process, what is the physics behind it?

[@nz1229]

Is there any way to deal with the scalloping seen at 8:50 and 11:45 without converting to db?

[@U_UPRETI]

How to prepare sediment map please?

[@danielalvesjati4755]

Very good. Thank you. How can I classify the area in red that represents the floodplains? I tried supervised sorting but it didn't work. I want to generate a shape only from the floodplain areas.

[@RolandoBustillo]

thanks this was very helpful after flood of 2018/oct/07 here at south of Honduras

[@EOCollege]

twitter.com/eo_college/status/1052483421006639104

[@RolandoBustillo]

haha thanks!

[@sasithasupun7946]

I need to export inundate areas only. How can i do that?

[@space-time-somdeep]

17:32 wow❤

[@coolsamuel4354]

So downloading the products has been a bit confusing to me, should I download SLC or Grid data?

[@felipefloresmeregote6642]

thank you! this was incredibly useful.

[@kuntheanuon8723]

Dear Sir, It took along time to run Geometric\Terrain Correction. I do not why ? please provide me an advices.

[@danielalvesjati4755]

What is the best polarization to detect water below the canopy of trees in flooded forest? It must be bands that cross the canopy to improve the estimate.

[@kevalan1042]

How important is the order of these operations? What if you do terrain correction before calibration?

[@محمدعكر-ح8ك]

PLZ, I want to know how to add the ٍِSARscape tool to my ENVI 5.3?

[@geoscientist650]

I used the valuable satellite data of Sentinel-1. If possible, guide me to fix the problem of image reversing

[@meridhohidayatullah4176]

I am very interested in the explanation and totorial you create. but because in my place of college still no one uses radar image for research final project. so I have to learn by myself about this image, see the explanation and totorial that you make make me lighter to learn it. I hope to discuss with you. thank you sir

[@AliRAl-Aizari]

Hi, I am a new user of SNAP toolbox. I am using sentinel 1 GRDH data for flood area identification. I have done everything until export file. After masking, I am trying to export data (view as Google Earth KMZ) but there have shown like this; SNAP-Error the image could not be exported . Could you please help me to finish this work?

[@yothinchanthasumlet4345]

the product does not exist with the coordinate system when I use Terrain Correction Tool. I need your help

[@izainanurfitriana7664]

Hi. I have a problem when stacking the 2 images. Error: org.jblas.NativeBlas.daemm (CIIIDDIDIDII). I have searched for the solution and found that I should install the libgfortran. I did that but the error still appears, Does anyone know how to solve it?

[@diegoasay4946]

Hello, what is the hardware recommended for an effective snap process?

[@donaldkiprotich8299]

How do we go about the same with Sentinel-2 images using SNAP

[@benten3125]

can you help me to get snaphu the phase unwrapping and the procedure for géocoding thanks for those videos

[@rumbidzaichivizhe5808]

hi Dr Stewart, what overall name is given to the method used in the video

[@javiergustavovillegas1254]

Stewart's

[@cesaraugustoarevalorivenso3551]

Hello, I am doing the practice with an area of Formosa (Argentina) that had floods in 2019. Now, I cannot perform the terrain correction, I give RUN and the machine keeps turning and it does not give me the result that I am expecting.

[@javiergustavovillegas1254]

No selecciones la opción de mascara

[@issak_vaiphei]

Sir, what does the mst and slv conveys in d stack image ?.

[@issak_vaiphei]

@Paul Sponagle no clue...

[@ekvinaysayaraj6071]

Dear Sir, very good material- I could follow it. However, after Terrain Correction for my case, it appear "no data" background. How do I remove it?

[@prosperwashaya3177]

did you figure out how to remove it?

[@kevalan1042]

What happens exactly when you calibrate sigma0?

[@almustafaayekRS]

Thanks 🎉❤

[@quocnguyen9901]

Why is my laptop when using SNAP, the laptop is frozen and does not work ??

[@andrijamitrovic7120]

SNAP requires a lot of RAM memory to work properly. It happened to me too, and i had to borrow a laptop from friend :D

[@benjamingkato8738]

Quoc Nguyen It depends what are your laptop specifications like RAM & the processor type...these are the key determinants

[@pantausumbar645]

Great...

[@prasenjitpal4919]

Hi sir, I have 1 question. How to calculate how much area are effected in flood.

[@Andreandthepenguin]

You can multiply the number of true pixels by the square of the nominal pixel size.

[@andrijamitrovic7120]

@@Andreandthepenguin How can i calculate the number of pixels that represent the area that is flooded?

[@Andreandthepenguin]

@@andrijamitrovic7120 To extract the areas of flooding, you can use either a thresholding method, a classification method, or you can manually digitize the areas of flooding. I prefer a simple fixed thresholding, using band math for a single flood event. If it's a time series, I use something like intermeans thresholding in a script. After that, there are multiple ways to calculate area. The quick and dirty way is to look in the metadata/properties of the output image to find the pixel count and nominal pixel resolution. Raster area = pixel count * pixel size (the area of one pixel). So, if you were working with landsat the area would be: [pixel count] * 30 * 30. I hope this helps.

[@andrijamitrovic7120]

@@Andreandthepenguin Thanks for your reply. I really appreciate it. I understood it. I was thinking about other method like if i have a area (raster picture in, lets say GEOTIFF format) of water during the flood and and area (raster) before the flood event. Could I open those images in Qgis and just use some operations in order to get a new raster that represents the area that is flooded (above lake level).

[@andrijamitrovic7120]

Update. Actually, in SNAP, this is a way to create water masks before and during the flood and then we can apply difference so we can get a new mask that is the flooded area only and then use raster-masks-mask area to calculate the surface that is flooded

[@kuntheanuon8723]

I do not know why? it took long time.

[@احمدكجاله]

Amazing Go ahead

[@HerrArcturus]

Thanks!

[@abdulkadirgure6940]

Hi mate! Can I Use Sentinel-2 or Sentinel-3

[@hervisghomsi2011]

Highly intituive

[@zainabkhan2475]

Not really impressed! :?

[@nimishapaul4093]

Dear Sir, very good material- I could follow it. However, after Terrain Correction for my case, it appear "no data" background. How do I remove it?

[@prosperwashaya3177]

did you ever figure out how to remove it?