undef

s1a-iw-grd-vv-20180409t173156-20180409t173225-021393-024d4d-001_filter

s1a-iw-grd-vh-20180409t173156-20180409t173225-021393-024d4d-002_filter

s1a-iw-grd-vv-20180409t173156-20180409t173225-021393-024d4d-001_winddir

s1a-iw-grd-vh-20180409t173156-20180409t173225-021393-024d4d-002_winddir