undef

s1a-iw-grd-vv-20170812t100920-20170812t100949-017889-01dff9-001_filter

s1a-iw-grd-vh-20170812t100920-20170812t100949-017889-01dff9-002_filter

s1a-iw-grd-vh-20170812t100920-20170812t100949-017889-01dff9-002_winddir

s1a-iw-grd-vv-20170812t100920-20170812t100949-017889-01dff9-001_winddir