add burst metadata: burst_duration & swath_name (#33)

+ s1_slc_burst: add two more metadata via @Property:
   - burst_duration
   - swath_name

+ README: update usage to load_bursts()

Co-authored-by: Liang Yu <[email protected]>

Author: yunjunz

README.md

@@ -52,7 +52,8 @@ orbit_dir = '/home/user/data/sentinel1_orbits'
 orbit_path = s1reader.get_orbit_file_from_dir(zip_path, orbit_dir)
 
 # returns the list of the bursts
-bursts = s1reader.burst_from_zip(zip_path, orbit_path, swath_num, pol)
+bursts = s1reader.load_bursts(zip_path, orbit_path, swath_num, pol)
+burst_ids = [x.burst_id for x in bursts]
 ```
 
 ### License

src/s1reader/s1_burst_slc.py

@@ -447,10 +447,27 @@ def sensing_stop(self):
         d_seconds = (self.length - 1) * self.azimuth_time_interval
         return self.sensing_start + datetime.timedelta(seconds=d_seconds)
 
+    @property
+    def burst_duration(self):
+        '''Returns burst sensing duration as float in seconds.
+
+        Returns:
+        --------
+        _ : float
+            Burst sensing duration as float in seconds.
+        '''
+        return self.azimuth_time_interval * self.length
+
     @property
     def length(self):
         return self.shape[0]
 
     @property
     def width(self):
         return self.shape[1]
+
+    @property
+    def swath_name(self):
+        '''Swath name in iw1, iw2, iw3.'''
+        return self.burst_id.split('_')[1]
+