02_UTCDateTime.ipynb

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        "<img src=\"https://raw.githubusercontent.com/seismo-live/seismo_live/refs/heads/master/notebooks/Workshops/2017_Baku_STCU_IRIS_ObsPy_course/images/obspy_logo_full_524x179px.png\" width=90%> "
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        "This is a bit dry but not very difficult and important to know. It is used everywhere in ObsPy!\n",
        "\n",
        "\n",
        "* All absolute time values are consistently handled with this class\n",
        "* Based on a double precision POSIX timestamp for accuracy\n",
        "* Timezone can be specified at initialization (if necessary)\n",
        "* In Coordinated Universal Time (UTC) so no need to deal with timezones, daylight savings, ...\n",
        "\n",
        "---"
      ]
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      "source": [
        "try:\n",
        "  import obspy\n",
        "except ModuleNotFoundError:\n",
        "  !pip -qq install obspy\n",
        "  import obspy"
      ]
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      "source": [
        "import matplotlib.pyplot as plt\n",
        "plt.style.use('ggplot')\n",
        "plt.rcParams['figure.figsize'] = 12, 8"
      ]
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      "source": [
        "---\n",
        "\n",
        "## Features of **`UTCDateTime`**\n",
        "\n",
        "#### Initialization"
      ]
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      "id": "c423b008",
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      "source": [
        "from obspy import UTCDateTime\n",
        "\n",
        "print(UTCDateTime(\"2011-03-11T05:46:23.2\"))        # mostly time strings defined by ISO standard\n",
        "print(UTCDateTime(\"2011-03-11T14:46:23.2+09:00\"))  # non-UTC timezone input\n",
        "print(UTCDateTime(2011, 3, 11, 5, 46, 23, 2))\n",
        "print(UTCDateTime(1299822383.2))"
      ]
    },
    {
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      "source": [
        "# Current time can be initialized by leaving out any arguments\n",
        "print(UTCDateTime())"
      ]
    },
    {
      "cell_type": "markdown",
      "id": "e2566748",
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      "source": [
        "#### Attribute Access"
      ]
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      "source": [
        "time = UTCDateTime(\"2011-03-11T05:46:23.200000Z\")\n",
        "print(time.year)\n",
        "print(time.julday)\n",
        "print(time.timestamp)\n",
        "print(time.weekday)\n",
        "# try time.<Tab>"
      ]
    },
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      "source": [
        "#### Handling time differences\n",
        "\n",
        "* \"**`+`**/**`-`**\" defined to add seconds to an **`UTCDateTime`** object\n",
        "* \"**`-`**\" defined to get time difference of two **`UTCDateTime`** objects"
      ]
    },
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      "source": [
        "time = UTCDateTime(\"2011-03-11T05:46:23.200000Z\")\n",
        "print(time)"
      ]
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      "id": "aeb58355",
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      "source": [
        "# one hour later\n",
        "print(time + 3600)"
      ]
    },
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      "id": "549d930c",
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      "source": [
        "time2 = UTCDateTime(2012, 1, 1)\n",
        "print(time2 - time)"
      ]
    },
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      "source": [
        "### Exercises\n",
        "\n",
        "Calculate the number of days passed since the Tohoku main shock (the timestamp used above)."
      ]
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      "id": "b837c23a",
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      "source": [
        "Make a list of 10 UTCDateTime objects, starting today at 10:00 with a spacing of 90 minutes."
      ]
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      "id": "13434ea6",
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      "source": [
        "Below is a list of strings with origin times of magnitude 8+ earthquakes since 2000 (fetched from IRIS). Assemble a list of interevent times in days. Use matplotlib to display a histogram."
      ]
    },
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        "times = [\"2001-06-23T20:33:09\",\n",
        "         \"2003-09-25T19:50:07\",\n",
        "         \"2004-12-23T14:59:00\",\n",
        "         \"2004-12-26T00:58:52\",\n",
        "         \"2005-03-28T16:09:35\",\n",
        "         \"2006-06-01T18:57:02\",\n",
        "         \"2006-06-05T00:50:31\",\n",
        "         \"2006-11-15T11:14:14\",\n",
        "         \"2007-01-13T04:23:23\",\n",
        "         \"2007-04-01T20:39:56\",\n",
        "         \"2007-08-15T23:40:58\",\n",
        "         \"2007-09-12T11:10:26\",\n",
        "         \"2009-09-29T17:48:11\",\n",
        "         \"2010-02-27T06:34:13\",\n",
        "         \"2011-03-11T05:46:23\",\n",
        "         \"2012-04-11T08:38:36\",\n",
        "         \"2012-04-11T10:43:10\",\n",
        "         \"2013-05-24T05:44:48\"]"
      ]
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