Implement time zone support

[infoex-autowx.git] / README.md

diff --git a/README.md b/README.md
index bebbdcb45c09172a3e79eb1e7be52f4d79f8090b..62d15bccc70b283bea0ca8bd646476957b22e9b7 100644 (file)
--- a/README.md
+++ b/README.md
@@ -83,6 +83,7 @@ options.
 `station_id = # the NRCS/MesoWest identifier for a particular station #`  
 `desired_data = # a comma-delimited list of fields you're interested in #`  
 `units = # either english or metric -- only applies when type is mesowest #`  
+`tz = # any entry from the Olson tz database e.g. America/Denver #`  
 `path = # the filesystem path to the Python program -- only applies when type is python #`  
 
 `[infoex]`  
@@ -206,6 +207,32 @@ or a remote web page which requires some custom parsing.
 Please see the program located at examples/custom-wx.example.py for a
 complete description of what's required.
 
+A note on time zones
+--------------------
+
+This program is aware of time zones via the pytz library. The way in
+which NRCS and MesoWest deal with time zones differs as follows:
+
+NRCS expects the request to come in the appropriate time zone, and the
+data retrieved will be in the same time zone (no transformation
+required before sending to InfoEx).
+
+MesoWest expects the request to come in UTC, and the data retrieved will
+be in the same time zone (transformation from UTC to the desired time
+zone is required before sending to InfoEx).
+
+As long as you specify the correct timezone in your configuration file,
+all will be handled correctly. The list of time zones comes from the
+Olson tz database. See that for more information.
+
+If you specify an invalid time zone, the program will exit and inform
+you of such.
+
+Lastly, InfoEx itself is timezone aware. If you notice that the data
+which makes it into your operation is inaccurate, start your
+investigation with time zone-related issues and move on only once you've
+ruled this out as a cause of the inaccuracy.
+
 A note on supported measurements
 --------------------------------