undef

s1a-iw-grd-vh-20170228t205933-20170228t205958-015489-01970a-002_filter

s1a-iw-grd-vv-20170228t205933-20170228t205958-015489-01970a-001_filter

s1a-iw-grd-vh-20170228t205933-20170228t205958-015489-01970a-002_winddir

s1a-iw-grd-vv-20170228t205933-20170228t205958-015489-01970a-001_winddir