NDVI and EVI time series from Sentinel-2 in Google Earth Engine [GEE]
HTML-код
- Опубликовано: 23 сен 2021
- Attempt to generate NDVI and EVI time series in Google Earth Engine.
I hope it is helpful. Any comments are welcomed.
-Thanks!
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Important Links:
1. @BjnNowak: [GEE] NDVI time series
bjnnowak.netlify.app/2021/09/...
2. Charts as easy as what, where, print by Google Earth (Mar 23, 2021) / charts-as-easy-as-what...
3. Python for Geosciences: Raster bit masks explained (step by step) by
Maurício Cordeiro (Mar 29, 2021) / python-for-geosciences...
4. Chart Overview developers.google.com/earth-e...
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#GEE #GoogleEarthEngine
#NDVI #EVI
![Forest Change Analysis in Google Earth Engine [GEE]](http://i.ytimg.com/vi/5oONMB0UPWc/mqdefault.jpg)
![Forest Change Analysis in Google Earth Engine [GEE]](/img/tr.png)
The codes are all adapted from the other sources.
However, if you want the codes, let me know through the channel's page (fb.com/ktmagarsYT ) or you can email me (email is in the channel's about section).
Thankyou for checking the video and comments section.
it says "This page isn't available"
@@qZoneful the link is fb.com/ktmagarsYT (the bracket causing the trouble) please check now.
@@ksabmagar7 thank you!
Really, It's helpful. Thanks for sharing!
Superbly done!
KT Thanks For Sharing this information its really help me alot.thanks you very much keep the good Work...
hi, Thanks so much for your kindness!. But it‘s said 'Content cannot be displayed at this time'on your FB, How could I get the code
Thanks for the helpful video and useful links. I am however getting a syntax error: Unexpected Token 10:1 upon entering the ".filter metadata..." line in the beginning. Any ideas what could cause this?
Thanks in advance!
filterMetdata function is already deprecated. You can check other ee.Filter functions to filter the metadatas. Check in the docs tab. -Thankyou for the comment
Image.select: Pattern 'SCL' did not match any bands. This error showing, how to solve it??
Please check the bands. There are different S2 data.
Hi, I am getting a computation timed out error while generating the chart (plotNDVI). Any idea to rectify this. Thanks in advance
Happens when your field area is big, probably choosing the small geometry or a point will solve this. Thankyou for the comment.
Thank you for the video. I used the code, it is working but i have a problem. I have two different NDVI values for the exactly same polygon at the same date. Probably there are two different image (maybe one night and one at day time?). What can be the reason and how can i solve it?
If your study area is too larger, there can be overlap of two tiers. If you check the image collections, there are images in the near/same dates, with different tiles.
You can separate your polygon making it may be small for your study area, may be taking average of all the NDVI values of the area.
I hope my comment helps
How are you trying to do with it?
-Thankyou :)
When I type geom.buffer the gee is showing it's not a function.
There might be mistake with the variable name. Check the variable name in the imports. -Thanks!
HI, thanks too much!! Is it possible to do the same with Landsat 5 e 8 collections? Thanks in advance
Yes, the process is the same.
If your plan is to use of Landsat 5 and 8 together, then it might needs further steps for harmonizing them. Otherwise, process for landsat 8 alone or (landsat 5 alone) is the same. The processing concepts are the same.
If you need further assistance, you are welcomed to message me in the page. This will also be a chance to practice more for me as well.
- thankyou for the subscribe.
thankyou! :)
Hello,
'nd' which band? When I write the 'nd' tape in the code I get this error:
pattern 'nd' did not match any bands.
Thanks in advance for your answer.
Hello,
The 'nd' is default when normalized difference function is applied. Obviously, when rename is applied, the name is something different. We can try printing the image or few images (if it's collection) to see what band has been added at the end. Also, we need to check the function to see if it's adding the band.
Hello, did you solve the error? :)
Simple question, but how do you de-comment several lines of code at once? Is there a shortcut for that?
Oh it is simple, anything within /*. */ are comments. They are called block comments. :)
@@ksabmagar7 Thank you!!
Hello sir
Can you please tell, while you calculating EVI so you divided band by 10000. what is the reason behind this ?
Hello sir, thankyou for the question.
We divide by 10000 as to work with the values conversion.
This is to change the given band values to 0 to 1. More precisely, we convert the data type from int16 to float data type in earth engine.
You can run this and check the data type
var S2 = ee.ImageCollection("COPERNICUS/S2_SR")
.first();
print('B8', S2.select('B8'))
print(S2.select('B8').divide(10000))
Or follow the conversation related to this: www.researchgate.net/post/How_might_one_scale_down_the_reflectance_values_in_the_range_0-1_from_landsat_8
Hope it helps.
Thankyou for the question.
@@ksabmagar7 Thank u sir for your reply. sir, I want to calculate EVI from combined (merged) image collection of Landsat-8 and Sentinel-2, and while is used this EVI formula in combining Landsat and sentinel data I got EVI value 0 for Landsat. therefore can you help me to overcome this problem?
@@ShriGT-DeepakVerma Combining the image collections might have been not easy as I can guess. Are you trying to perform this in earth engine. If both landsat and sentinel is being talked, I think there is already data prepared for this.
If you are not aware about it. please check this. lpdaac.usgs.gov/data/get-started-data/collection-overview/missions/harmonized-landsat-sentinel-2-hls-overview/
May be that data can be downloaded and further worked on earth engine. Is my comment helpful in anyway?
Please message me in the facebook page for more discussion.
fb.com/ktmagarsYT
Please Can in get this code
Please email.
Sir please make an atmosphere correction tutorial for Sentinel-2 level 1C data using the Google Earth engine because for my final project, I don't know who to ask anymore 🙏
Hello, I will try exploring it may be in future content as I am a learner too.
May be this discussion might help for now. www.researchgate.net/post/Atmospheric_correction_code_in_Google_Earth_Engine_GEE
Or message in the facebook page if you need more help.
Thankyou
There is a short content now. ruclips.net/user/shortsCy1etLb0kv4
can i get this code
Hi there, you can check the codes from the important links in the description. All the codes are from the developers.google.cn/earth-engine/guides?hl=zh-cn
You can find the main codes here:
bjnnowak.netlify.app/2021/09/10/gee-ndvi-time-series/
Thanks!
It is a helpful video and I liked it . May I get the code plse?
Please message me. thankyou.
Hi, could you please share the code? Thanks
Please message in the fb page.
I din't find your email id on your page and page is showing page not found.
please check about section.
@@ksabmagar7 I check it but it is not there. Could you share your email here
@@muddasirahmadakhoon6044 yes, email me in ksabmagar7@gmail.com, you could have found in ABOUT section of the channel. -thankyou
Thank you for sharing.
I would like to learn Google Earth Engine, I was not able to create an account. I ask for your help to create an account.
Go to this link and try signing up.
If your current gmail doesnot work, try another gmail account.
Link: signup.earthengine.google.com/
-Thanks!
Could u provide me NDVI and EVI time series from Sentinel-2 in Google Earth Engine [GEE] codes please .
please email me.
@@ksabmagar7 Thanks 4 help.
:)
Code plz
You can find the codes from the relevant links from the description. Or email me if you want to the codes. The email is in about section. -Thankyou : )
@@ksabmagar7 email?
Mention email plz
@@fakharulislam2519 Please check the about section: ruclips.net/user/ktmagarsYTabout
or message me in the page fb.com/ktmagarsYT
Hello,
Thanks for the tutorial. I keep getting this error when I tried to create chart using shapefile.
Collection.first: Projection error: Unable to compute intersection of geometries in projections SR-ORG:6974: affine [231.65635826395825, 0.0, -2.0015109354E7, 0.0, -231.65635826395834, 1.0007554677003E7] and EPSG:4326: affine [1.0, 0.0, 0.0, 0.0, 1.0, 0.0].
How can I resolve this please
Can you try changing the projections of image. The projections of modis might be causing that. developers.google.com/earth-engine/guides/projections
@@ksabmagar7 Many thanks