undef

s1a-iw-grd-vh-20180918t131447-20180918t131512-023753-029725-002_filter

s1a-iw-grd-vv-20180918t131447-20180918t131512-023753-029725-001_filter

s1a-iw-grd-vh-20180918t131447-20180918t131512-023753-029725-002_winddir

s1a-iw-grd-vv-20180918t131447-20180918t131512-023753-029725-001_winddir