undef

s1a-ew-grd-vv-20180304t145347-20180304t145451-020866-023ca4-001_filter

s1a-ew-grd-vh-20180304t145347-20180304t145451-020866-023ca4-002_filter

s1a-ew-grd-vh-20180304t145347-20180304t145451-020866-023ca4-002_winddir

s1a-ew-grd-vv-20180304t145347-20180304t145451-020866-023ca4-001_winddir