undef

s1a-iw-grd-vh-20170815t205942-20170815t210007-017939-01e17a-002_filter

s1a-iw-grd-vv-20170815t205942-20170815t210007-017939-01e17a-001_filter

s1a-iw-grd-vh-20170815t205942-20170815t210007-017939-01e17a-002_winddir

s1a-iw-grd-vv-20170815t205942-20170815t210007-017939-01e17a-001_winddir