Is it possible to check the flatness(OSNR) of a trail in a single click in every point?

Good question! I want to know it too!

Yes, you can select an OCh trail from the navigation tree and click the OSNR tab to view the OSNR value of the optical interface. The diagram shows whether the performance deteriorates.

Nice! Good answer! Thanks a lot!

For checking OSNR you better have Optical Doctor version 2 (ODv2) function in your system. This is required hardware (MCA, OPM and so on) and software support on NE and U2000. After you configure ODv2 you can get something like this:

Moreover, you will have some automatic system to adjust trails performance and many more functions. Please found documentation "Optical Doctor System Feature Description" on Huawei support site.