undef

s1a-iw-grd-vh-20170506t102452-20170506t102521-016460-01b44a-002_filter

s1a-iw-grd-vv-20170506t102452-20170506t102521-016460-01b44a-001_filter

s1a-iw-grd-vh-20170506t102452-20170506t102521-016460-01b44a-002_winddir

s1a-iw-grd-vv-20170506t102452-20170506t102521-016460-01b44a-001_winddir