[weather.metoffice] v4.1.0

weather.metoffice/addon.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<addon id="weather.metoffice" version="4.0.0" name="Met Office" provider-name="powlo">
+<addon id="weather.metoffice" version="4.1.0" name="Met Office" provider-name="powlo">
   <requires>
     <import addon="xbmc.python" version="3.0.0" />
     <import addon="script.module.pytz" version="2014.2" />

weather.metoffice/changelog.txt

@@ -25,4 +25,8 @@ v3.0.0
 v4.0.0
 - Cleaned up memory leaks
 - Removed unused imaging code.
-- Removed default API key and nudged user to get their own.
+- Removed default API key and nudged user to get their own.
+
+v4.1.0
+- Added feels like calculation.
+- Updated geoip providers.

weather.metoffice/resources/settings.xml

@@ -19,7 +19,7 @@
     <setting id="ApiKey" label="32003" type="text" default="a5408080-80af-44ea-b3a6-b86d320dc706" />
     <setting id="GeoLocation" label="32004" type="bool" default="true" />
     <setting id="GeoIPProvider" label="32005" type="enum"
-      values="www.ip-api.com|www.freegeoip.net|www.geoiplookup.net" enable="eq(-1,true)" default="0" />
+      values="www.ip-api.com|www.geoiplookup.net|www.ipapi.co" enable="eq(-1,true)" default="0" />
     <setting id="EraseCache" label="32006" type="bool" default="false" />
   </category>
 </settings>

weather.metoffice/src/default.py

@@ -16,6 +16,7 @@
 # *  http://www.gnu.org/copyleft/gpl.html
 import socket
 import sys
+import traceback
 from urllib.error import HTTPError
 
 import xbmc
@@ -54,7 +55,13 @@ def main():
         properties.daily()
         properties.threehourly()
         properties.sunrisesunset()
+    except KeyError:
+        # Expect KeyErrors to come from parsing JSON responses.
+        # This is considered an intermittent error, so exception is eaten.
+        utilities.log(traceback.format_exc(), xbmc.LOGERROR)
     except HTTPError:
+        # HTTPErrors are most likely to occur when the user hasn't set their API
+        # key, so allow the script to raise to produce a parp.
         utilities.log(
             (
                 "Error fetching data.\n"

weather.metoffice/src/metoffice/constants.py

@@ -104,12 +104,12 @@ def addon():
 GEOIP_PROVIDERS = [
     {"url": "http://ip-api.com/json/", "latitude": "lat", "longitude": "lon"},
     {
-        "url": "http://freegeoip.net/json/",
+        "url": "https://api.geoiplookup.net/?json=true",
         "latitude": "latitude",
         "longitude": "longitude",
     },
     {
-        "url": "http://geoiplookup.net/geoapi.php?output=json",
+        "url": "https://ipapi.co/json/",
         "latitude": "latitude",
         "longitude": "longitude",
     },

weather.metoffice/src/metoffice/properties.py

@@ -69,7 +69,13 @@ def observation():
         )
         window().setProperty("Current.FeelsLike", "n/a")
         # if we get Wind, then convert it to kmph.
-        window().setProperty("Current.Wind", utilities.mph_to_kmph(latest_obs, "S"))
+        wind_speed = latest_obs.get("S")
+        if wind_speed:
+            window().setProperty(
+                "Current.Wind", str(round(utilities.mph_to_kph(float(wind_speed)), 0))
+            )
+        else:
+            window().setProperty("Current.Wind", "n/a")
         window().setProperty("Current.WindDirection", latest_obs.get("D", "n/a"))
         window().setProperty("Current.WindGust", latest_obs.get("G", "n/a"))
         window().setProperty(
@@ -83,6 +89,20 @@ def observation():
             "Current.DewPoint",
             str(round(float(latest_obs.get("Dp", "n/a")))).split(".")[0],
         )
+        humidity = latest_obs.get("H")
+        temperature = latest_obs.get("T")
+        if humidity and temperature and wind_speed:
+            ws_mps = utilities.mph_to_mps(float(wind_speed))
+            feels_like = utilities.feels_like(
+                float(temperature), float(humidity) / 100, ws_mps
+            )
+            window().setProperty(
+                "Current.FeelsLike",
+                str(round(feels_like)),
+            )
+        else:
+            window().setProperty("Current.FeelsLike", "n/a")
+
         window().setProperty(
             "Current.Humidity",
             str(round(float(latest_obs.get("H", "n/a")))).split(".")[0],

weather.metoffice/src/metoffice/utilities.py

@@ -7,13 +7,8 @@
 import xbmc
 import xbmcgui
 
-from .constants import (
-    ADDON_BROWSER_WINDOW_ID,
-    TEMPERATUREUNITS,
-    WEATHER_WINDOW_ID,
-    addon,
-    dialog,
-)
+from .constants import (ADDON_BROWSER_WINDOW_ID, TEMPERATUREUNITS,
+                        WEATHER_WINDOW_ID, addon, dialog)
 
 
 def log(msg, level=xbmc.LOGINFO):
@@ -119,6 +114,86 @@ def haversine_distance(lat1, lon1, lat2, lon2):
     return EARTH_RADIUS * c
 
 
+def feels_like(temp, humidity, windspeed):
+    # https://blog.metoffice.gov.uk/2012/02/15/what-is-feels-like-temperature/
+    # Using these facts we use a formula to adjust the air temperature based
+    # on our understanding of wind chill at lower temperatures, heat index at
+    # higher temperatures and a combination of the two in between.
+
+    # Inspect temperature and humidity to determine which functions below
+    # should be applied.
+
+    # But for now just use the 'simplified' apparent temperature.
+    return apparent_temperature_simplified(temp, humidity, windspeed)
+
+
+def water_vapour_pressure(t, rh):
+    # Temperature (t) is a float from 0 to 100 representing a temperature in degrees C.
+    # Relative humidity (rh) is a float from 0.00 to 1.00 representing a percentage.
+    return rh * 6.105 * math.e ** (17.27 * t / (237.7 + t))
+
+
+def apparent_temperature_simplified(t, rh, ws):
+    # A version of apparent temperature that doesn't need Q factor.
+    # From the Land of Oz.
+    # https://www.vcalc.com/wiki/rklarsen/Australian+Apparent+Temperature+%28AT%29
+    hPa = water_vapour_pressure(t, rh)
+    return t + (0.33 * hPa) - (0.70 * ws) - 4.00
+
+
+def apparent_temperature(t, rh, ws, Q=0):
+    # https://calculator.academy/apparent-temperature-calculator/
+    # temp in degrees C
+    # humidity ...
+    # windspeed in metres per second
+    # TODO: Q is a fudge factor based on absorbed solar radiation.
+    hPa = water_vapour_pressure(t, rh)
+    return t + 0.38 * hPa - 0.70 * ws + 0.70 * (Q / (ws + 10)) - 4.25
+
+
+def wind_chill(temp, windspeed):
+    # Use wind chill at lower winter temperatures.
+    return (
+        13.12
+        + 0.6215 * temp
+        - 11.37 * windspeed**0.16
+        + 0.3965 * temp * windspeed**0.16
+    )
+
+
+def heat_index(t, r):
+    # Use heat index for high summer temperatures.
+    """
+    See: https://en.wikipedia.org/wiki/Heat_index
+    The formula below approximates the heat index in degrees Fahrenheit,
+    to within ±1.3 °F (0.7 °C). It is the result of a multivariate fit
+    (temperature equal to or greater than 80 °F (27 °C)
+    """
+
+    # NB!!! rh here is a percentage expressed as 0 - 100!
+
+    c1 = -8.78469475556
+    c2 = 1.61139411
+    c3 = 2.33854883889
+    c4 = -0.14611605
+    c5 = -0.012308094
+    c6 = -0.0164248277778
+    c7 = 0.002211732
+    c8 = 0.00072546
+    c9 = -0.000003582
+    return (
+        c1
+        + c2 * t
+        + c3 * r
+        + c4 * t * r
+        + c5 * (t**2)
+        + c6 * (r**2)
+        + c7 * (t**2) * r
+        + c8 * t * (r**2)
+        + c9 * (t**2) * (r**2)
+    )
+
+
 def rownd(x):
     try:
         return str(round(float(x), 0)).split(".")[0]
@@ -142,13 +217,17 @@ def localised_temperature(t):
 
 
 @f_or_nla
-def mph_to_kmph(obj, key):
+def mph_to_kph(x):
     """
     Convert miles per hour to kilomenters per hour
     Required because Kodi assumes that wind speed is provided in
     kilometers per hour.
     """
-    return str(round(float(obj[key]) * 1.609344, 0))
+    return x * 1.609344
+
+
+def mph_to_mps(x):
+    return x / 2.237
 
 
 def gettext(s):