[Weather] Documentation problem about snow item unit

[emme-g]

Hello, in the place where I live is going to snow in the next hours, so I checked my Openhab2 system where I recently added more forecast item from the Weather binding to see if the precipitation-snow item would signal that and: yes, the number item is not null and gives me the information that I'm going to see outside a 0.5 mm/h snowfall! That 0.5 mm/h seemed to me a little bit too precise so I've checked in the binding documentation page and I found a contradiction in it:

• in the "Unit conversion" section is written that snow has cm as default unit;
• in the "Items" section the unit for the precipitation-snow item is mm/h. I think it would be good to clear if the units of the information given through this item are mm, mm/h, cm or cm/h. I guess the last option could be the right one but I think it would be better if one of the binding developers could specify that. Bye.

[cweitkamp]

The snow volume is given in mm/h (see http://openweathermap.org/weather-data). OWM API returns a value for the next three hours. The binding converts it to one hour.

I will clean up the documentation.

[cweitkamp]

After looking into it I'm sure we have to do some more tweaking. The binding provides the data for snowfall for the following three providers: https://github.com/openhab/openhab1-addons/blob/eb78378754a8d8761f3cb9d52c7a31e45a5e7f2e/bundles/binding/org.openhab.binding.weather/src/main/java/org/openhab/binding/weather/internal/model/Precipitation.java#L36-L41

Weather Underground returns a value in cm / day, OpenWeaterMap returns a value in mm / 3h (is converted to mm / h by the binding) and HAMweather returns a value in mm (no information about any period). This has to be unified.

@emme-g Which weather provider do you use?

[emme-g]

Hi, thank you for taking care of this problem. I'm using Wunderground as weather data provider, so it means that the number I red yesterday in my item indicated a probability for a snowfall of about 0,5 cm (for all the day). I agree with you when you write that would be better to unify the information given by the binding, the meaning of the value shouldn't be affected from the chosen whether data provider. If that would result difficult to achieve, I think that at least that should be clearly documented. Let me know if I can help anyhow for this modification process (I'm not it-professional but I'm available if needed), and thank you again. Bye.