Added a module for utility functions

pytorch/utils.py

+# -*- coding: utf-8 -*-
+"""
+Created on Tue Jul 14 15:02:23 2020
+
+@author: Daniel
+"""
+# builtins
+import re
+import datetime
+
+
+def parse_landsat8_date(scene):
+
+    # Landsat Collection 1 naming convention in regular expression
+    sensor = 'L[COTEM]0[1-8]_'
+    level = 'L[0-9][A-Z][A-Z]_'
+    swath = '[0-2][0-9]{2}[0-1][0-9]{2}_'
+    date = '[0-9]{4}[0-1][0-9][0-3][0-9]_'
+    doy = '[0-9]{4}[0-3][0-9]{2}'
+    collection = '0[0-9]_'
+    category = '[A-Z]([A-Z]|[0-9])'
+
+    # Landsat Collection 1 naming
+    C1 = (sensor + level + swath + date + date + collection + category)
+    Landsat_C1 = re.compile(C1)
+
+    # Landsat naming convention before Collections
+    C0 = (sensor.replace('_', '').replace('0', '') + swath.replace('_', '') +
+          doy + '[A-Z]{3}' + '[0-9]{2}')
+    Landsat_C0 = re.compile(C0)
+
+    # whether a scene identifier matches the Landsat naming convention
+    # if True, get the date of
+    date = None
+    if Landsat_C0.match(scene):
+        date = doy2date(scene[9:13], scene[13:16])
+    if Landsat_C1.match(scene):
+        date = datetime.datetime.strptime(scene.split('_')[3], '%Y%m%d')
+
+    return date
+
+
+def parse_sentinel2_date(scene):
+
+    # Sentinel 2 Level-1C products naming convention after 6th December 2016
+    mission = 'S2[A-B]_'
+    level = 'MSIL1C_'
+    date = '[0-9]{4}[0-1][0-9][0-3][0-9]'
+    time = 'T[0-2][0-9][0-5][0-9][0-5][0-9]_'
+    processing = 'N[0-9]{4}_'
+    orbit = 'R[0-1][0-9]{2}_'
+    tile = 'T[0-9]{2}[A-Z]{3}_'
+    level_1C = (mission + level + date + time + processing +
+                orbit + tile + date + time.replace('_', ''))
+    S2_L1C_New = re.compile(level_1C)
+
+    # Sentinel 2 Level-1C products naming convention before 6th December 2016
+    file_class = '[A-Z]{4}_'
+    file_category = '[A-Z]{3}_'
+    file_semantic = 'L[0-1]([ABC]|_)_[A-Z]{2}_'
+    site = '[A-Z_]{4}_'
+    aorbit = 'A[0-9]{6}_'
+    S2_L1C_Old = re.compile(mission + file_class + file_category +
+                            file_semantic + site + 'V' + date + time + aorbit +
+                            tile.replace('_', ''))
+
+    # ProSnow project naming convention
+    ProSnow = re.compile(tile + date + time.replace('_', ''))
+
+    # whether a scene identifier matches the Landsat naming convention
+    # if True, get the date of
+    date = None
+    if S2_L1C_Old.match(scene):
+        date = datetime.datetime.strptime(
+            scene.split('_')[7].split('T')[0].replace('V', ''), '%Y%m%d')
+    if S2_L1C_New.match(scene):
+        date = datetime.datetime.strptime(scene.split('_')[2].split('T')[0],
+                                          '%Y%m%d')
+    if ProSnow.match(scene):
+        date = datetime.datetime.strptime(scene.split('_')[1].split('T')[0],
+                                          '%Y%m%d')
+
+    return date
+
+
+def doy2date(year, doy):
+    """Converts the (year, day of the year) date format to a datetime object.
+
+    Parameters
+    ----------
+    year : int
+        the year
+    doy : int
+        the day of the year
+
+    Returns
+    -------
+    date : datetime.datetime
+        the converted date as datetime object
+    """
+
+    # convert year/day of year to a datetime object
+    date = (datetime.datetime(int(year), 1, 1) +
+            datetime.timedelta(days=(int(doy) - 1)))
+
+    return date