Missing section in band math


l am trying calculate LAİ in band math. But when edit expression there is no show data name (products name). in second mage it can see there is product name. but in my snap software does not have and that is why l can’t change product name.

you can only select the product in the top when there are multiple products opened in SNAP which have exact the same dimensions (columns and rows).

l did that and get black image. you can see in bottom of first image. cause index is lai - lai. but it should be $3.LAI - $2.LAI if l want get result.

As Andreas said, the two products you are using probably don’t have the same size.
You can check this by selecting the product and the opening of the information view (Analysis / Information).

İs it differ S2A and S2B resolution?

I just tried it myself and the S2A and S2B products are identical regardin extent and pixel size, so they are interchangable in the Band Maths

Maybe you have applied some pre-processing?
As @marpet suggests, you can check the metadata if they have the same geometries. If not, you can use the collocation tool to make one stack of all your LAI products and then combine them in the band maths.

Thanks. yeah my 2 data is a little differ and that made problem to display in band math.
how may l cut one image by another image border?

The best approach is probably to collocate (Raster / Geometric Operation / Collocation) both into one product.
Also creating a subset on both products by geo-coordinates should work.

I think this is quite prone to errors for small pixel sizes or shifted alignment of two products.

I agree that collocation is the best way to bring several rasters into the same geometry.