tidetable 0.1.2

Time frames

By default, the NOAA returns the tide prediction table for the current year. To get years in the recent past or future, use the year keyword argument. It seems that roughly five years in the past and two years in the future are available. There isn’t a way to get smaller time ranges of predictions than a full year.

>>> import tidetable
>>> table = tidetable.get(8416092, year=2016)
>>> table
tidetable.TideTable(stationid=8416092)
>>> table[4]['datetime']
datetime.datetime(2016, 1, 1, 3, 39)

(Note that the first few rows returned may be for the previous year.)

Writing

The TideTable object has a write_csv method. It accepts either a file name or any file-like object.

import tidetable
table = tidetable.get(8416092)
table.write_csv('tide_table.csv')

Time zones

As you can see, TideTable is a list of dicts, each of which has a datetime, a prediction in feet and cm, and a high-or-low flag. The predictions are relative to the datum, which in this case is MLLW, or the mean lower low water level. Note that MLLW is different from sea level.

By default, the datetime is in the local time, which could be standard or daylight savings time. Use the time_zone keyword argument to fetch times in either GMT or the local standard time zone. TideTable always returns naive datetime objects.

Use these constants for specifying the time zone: tidetable.GMT, tidetable.LOCAL_STANDARD_TIME, tidetable.LOCAL_TIME.

>>> import tidetable
>>> table = tidetable.get(8416092, time_zone=tidetable.GMT)
>>> table[0]['datetime']
datetime.datetime(2014, 12, 31, 0, 15)

(Note the difference from the datetime in the first example, which is in Eastern Standard Time)