after following your step ,i got this classification
can help in identifying the black area
as that is a river area, but i made two classes blue showing water area , then why black?
and what does confidence image tells.
after following your step ,i got this classification
areas which are not classified do not fulfill the confidence criterion of Random Forest, that means they cannot be assigned to one of the classes.
You should read a bit about the classifier before applying it:
http://wgrass.media.osaka-cu.ac.jp/gisideas10/papers/04aa1f4a8beb619e7fe711c29b7b.pdf
Please also use the search function for common questions:
Did you uesd the raster layer to train the samples ?there I had uesd the raster to classfy the study areas with 3 types .if you do please tell me .
you see in the screenshot that she used training vectors (red squares).
You can only use rasters as training inputs if they represent the final classes (e.g. land cover maps).
Please have a look here: Supervised and unsupervised classification, Sentinel 2
Classification of S2 products only works with reprojected data, please have a look here:
thank you sir ,i had get it.
dear ABraun sir,I had a train classification results,as follows,but it failed when i try to run the RFclassfication(my study area is moutain glacier ,need to classfied with wet snow,dry snow ,moranie,and ice) [图片]
please specify the problem.
Dear @ABraun,
I am running Random Forest to classify a stack image (between SAR band and several texture band created from DEM). Bearing in mind that Random Forest can work with data quite flexibly. However, I faced this error and did not know why. Do you have a clue for that?
Thank you!
Another issue is my stacking image could not be opened (after subsetting and applying Land/sea mask). And I don’t know why. Can you please help me to solve it?
the NullPointerException is not telling us much about the source of the error, but we can try to narrow it down.
Dear @ABraun
messages.log (149.5 KB)
I try to reproject, and it could not be done with the below message.
I check the data layer properties and remove all the check mark in row No Data value Used, then save it and run the classification again. It still does not work with the red words at the bottom of the dialog “Incomplete expression”
please completely remove all the geometries from the product, save it and import them again.
If the RF works with the Sigma0 bands, there is something wrong with the texture layers. Please check the valid pixel expressions again if you have left a character or something (Missing ‘)’ sounds like there is an incomplete statement)
These are Floating point and Unsigned 8 bit data.
Do you mean some pixels were not Digital Number value?
the classifier wants to extract all pixel values under the training geometries. If one of them is defined as NaN (not a number) defined in the band properties. These are displayed transparent in SNAP.
Please also see here: Polarimetric Classification NaN problem
Please try -9999 for no data in all bands and save the product
Dear @ABraun,
I carefully check the input data;
Remove all the “Valid Pixel Expression”;
Un-check the No-Data Value Used
Set the Nodata as 0;
Save the product;
Then run the RF.
The message now as below: Java.lang.NullPointerException
It is really strange ;(