Re: [weewx-user] Convert values before loading into database

['John Kline' via weewx-user]

IIRC, When your driver creates loop and archive observations, you need to set usUnits to reflect the correct system.  For example, the vantage drive sets: 'usUnits': weewx.US In the loop data and archive records. If custom driver is in metric, set: ‘UsUnits’: weewx.METRIC If you do this, weewx will do the conversions and store values in the database in the system you specified when you created the database. But there is more.  You have to use the correct metric units.  To do this, see the weewx/units.py file.  Look up the observation in that file, find the group, and then look up what that group expects. For example, rain is: "rain"                      : "group_rain", And, if you look up group_rain for metric, you’ll find group_rain is expecting cm: "group_rain"        : "cm", # This dictionary maps unit groups to a standard unit type in the # metric unit system:            MetricUnits = ListOfDicts({          "group_altitude"    : "meter",     "group_amp"         : "amp",     "group_angle"       : "degree_angle",     "group_boolean"     : "boolean",     "group_concentration": "microgram_per_meter_cubed",     "group_count"       : "count",     "group_data"        : "byte",     "group_db"          : "dB",     "group_degree_day"  : "degree_C_day",     "group_deltatime"   : "second",     "group_direction"   : "degree_compass",     "group_distance"    : "km",     "group_elapsed"     : "second",     "group_energy"      : "watt_hour",     "group_energy2"     : "watt_second",     "group_fraction"    : "ppm",     "group_frequency"   : "hertz",     "group_illuminance" : "lux",     "group_interval"    : "minute",     "group_length"      : "cm",     "group_moisture"    : "centibar",     "group_percent"     : "percent",     "group_power"       : "watt",     "group_pressure"    : "mbar",     "group_pressurerate": "mbar_per_hour",     "group_radiation"   : "watt_per_meter_squared",     "group_rain"        : "cm",     "group_rainrate"    : "cm_per_hour",     "group_speed"       : "km_per_hour",     "group_speed2"      : "km_per_hour2",     "group_temperature" : "degree_C",     "group_time"        : "unix_epoch",     "group_uv"          : "uv_index",     "group_volt"        : "volt",     "group_volume"      : "liter" }) On Oct 2, 2024, at 7:51 PM, Thomas Carlin <thomascarl...@gmail.com> wrote: I have a sensor that is adding data to WeeWX with a custom driver.  Unfortunately, the sensor provides values in various metric units, C, hPa, µg/m³, things like that.  Obviously it is not a big deal to write these conversions into the driver, but i am curious if there is a prebuilt mechanism to convert them before they go into the database.  Obviously, we can do the conversions after the fact, but logically it is better to convert and store everything in the same units.   Do i need to do the conversions in the driver, or is there a way built into WeeWX? Many thanks! -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to weewx-user+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/weewx-user/e8e19545-1c1b-43b7-8a07-472f5daa4232n%40googlegroups.com. -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to weewx-user+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/weewx-user/7862DA18-FA9F-4B63-88AF-C8355C8D3AC2%40johnkline.com.