FAI Pixel Count with Sentinel 2A


I am using an image from S2A and applied the FAI algorithm for Hu et al. (2009). A mask was build and applied for land pixels. so, I was wondering if it was possible to calculate how many FAI pixels that image has?

You can use the Statistics tool in the Analysis section. Open your image and select Statistics. There you can choose your ROI mask to calculate the statistics (number of pixels, min value, max value, average, etc) and to visualise the histogram and the percentile plots.

How can I convert my product to a mask?

You can create one in the mask manager using the band information as criterion, e.g. FAI > 0

Is there any chance that I can get how many fai pixels are available in km or meters? I tried creating a mask as mentioned before.

I don’t know if I am doing it right.

Yes, that’s okay. But the value is rounded.
10m² resolution of B4 in your S2 data means:
This times 28 pixels is 0.0028km²
Rounded to 0.003 as shown in the image.