Extract shapefile after k-means classification

hi,
i would extract a polygons in purple from my image… the image was obtain from unsupervised classification and the values are 1 for the purple zones and 0 for the yellow zones

I have just tried use band maths for visualized only the purple zones, but I can’t to export them as shapefile

any advice?

thanks

SNAP does currently not support exporting vector polygons.

ah okay no problem. I will export it as geotiff and then process in Qgis or R.

thank you