Calculate NDVI from Sentinel 2 and reclassify in QGIS

QGIS 3.16.5 was used, because it's the current LTR version.

This video is part of IHE Delft OpenCourseWare and was included in the Training of Trainers 1 course for the WaterPIP Knowledge Hubs.

Apologies for the sound quality...

#IHEDelft #QGIS #GISOCW

[dianaswidler]

Thank you so much! I learned a lot and it is very easy to follow!

[elizavetakostromina]

Thank you so much for the video! it was very useful and easy to understand, it helped me a lot!

[anjaneyahk]

Thank you Sir for very informative video.

[dopamining]

Hey Hans, do you know how I should handle clouds?
I see this is possible with cloud masking, but it seems I would need to figure out how to apply this in google earth engine or something..
Is it a better idea to get multiple layers over a month or so to subtract the clouds out?

[JC-gpbd]

There isnt a Sentinel option anymore, any idea why?

[Malizfk]

Excuse me. If i want to get NDVI data from each pixel by using sentinel 2 data how can i do? or it can't (I try to use sentinel 2 data to calculate carbon collected from tree in small space) (Sorry if my eng was bad) Thank you!!

Dear Dr. Hans van der Kwast. Thank you so much for such a wonderful video. I was comparing Landsat 9 (OLI) and Sentinel 2 (Level 2A) BOA images. I used different vegetation indices including NDVI and MNDWI. However, the BOA (L2A) NDVI looks weird. Do you recommend using Level 1C or L2A for vegetation indices? Thanks

[ezequielorquera]

Thanks! Excellent video.
One Q: Should we first calibrate the L1 image to surface reflectance?

[wenchen]

Thank you very much for this tutorial. One question: how can we calculate annual NDVI or monthly NDVI?

[WilliamBelini]

Can determine the area by color in hectares?

[tegarnalle]

How to classify and put the scale range for mangrove vegetation

[carlaocano]

thank you so much for the video. Do you know how to combine sentinel 2 images with black parts in the same raster??

[megan]

Hi, does this method only work for Sentinel 2 L1C data or does it also work for L2A? I have very differing results (some working, some anomalous) and I am wondering if it is because I used Sentinel L2A?

[kategeorge]

Hi, thanks for your great video. When I did the raster calculation for NDVI it did not work. Appeared to calculate but did not show a layer. I checked correct projection and correct expression. Any ideas where I have gone wrong. Thanks

[megan]

when you do the ndvi do you need to save it within the folder of the Sentinel data e.g., the one starting with S2B_MSI etc., ? Whenever I do the NDVI calculation it never comes up with -1 to 1 as the limits - always random numbers in between this. Do you know why this might be please?

[brilianfifarsyah]

when doing reclassify, mine is not working and it says 'invalid value for maximum: 0, 1'. can you help me with this? thanks

[nailujretuas]

Thank you for the highly helpful video! I want to do the same procedure but with data for the country of germany. I can't find a fitting dataset on earthexplorer and the website won't let me upload the shapefile of germany since the polygone has more than 30 lines. Do you know where I can get the data? Again thank you for your help!

[mrx-inxh]

Hi thanks for the video. I just tried uploading a watershed KML file and I got an error telling me that the file is greater than 500 points. Is there a workaround to this limitation? thx

[josegarcia]

Hi Hans. Thanks for that video. How can I extract a % per band?? I need to clasify a percentage per band to monitor a crop over time?

[megan]

When calculating the NDVI in the raster calculator the output is never -1 to 1 - it’s always something like -0.7 to 0.6 which really messes up my NDVI map. Is there anything I can do to fix this? Thank you for all your responses to my questions!!