Check if UNW is missing from the metadata

[webgisdeveloper]

[webgisdeveloper]

Examples:

# Ground Range Unwrapped Phase                   (&)             = SanAnd_23513_17112-004_18072-007_0352d_s01_L090HH_02.unw.grd     ; File Size           0 bytes
# Ground Range Unwrapped Phase                   (&)             = harvrd_18501_09063-002_09063-004_0000d_s01_L090HH_02.unw.grd     ; File Size   230940780 byte
# Ground Range Unwrapped Phase                   (&)             =  N/A