Thanks Tom for the pointer. Already busy implementing Op zaterdag 23 mei 2020 02:52:39 UTC+2 schreef Tom Keffer: > > Sounds like a perfect job for the xtypes system. See this wiki article: > *WeeWX > V4 user defined types (xtypes)* > <https://github.com/weewx/weewx/wiki/WeeWX-V4-user-defined-types>. See if > it answers your question. > > If you define a derived variable using xtypes, it becomes a first-class > type and can be used in plots, or tagged expressions. If it appears in your > database schema, it will also be put in the database. > > -tk > > On Fri, May 22, 2020 at 7:14 AM Maarten van der Hoeven <hoev...@gmail.com > <javascript:>> wrote: > >> Hi group, >> >> Running weewx 4, Python 3, Mysql-database, Vantage Pro 2 with solar, UV. >> >> Within Weewx, I want to calculate a derived value from two existing >> values that's provided by my weather station. To be more specific, in the >> Netherlands, the shortage of precipitation is calculated by the amount of >> rainfall minus the amount of evapotransipration (sum of max ET-values every >> day). During the period of april till september, it;'s a drought indicator. >> >> My SQL-query to do show is, where 'tekort' (Dutch) stands for >> 'shortage'. >> >> select abs(round(sum(archive_day_rain.sum)-sum(archive_day_ET.sum),0)) as >> tekort from archive_day_ET,archive_day_rain where >> from_unixtime(archive_day_rain.datetime,'%Y')=year(curdate()) and >> month(from_unixtime(archive_day_rain.datetime)) >= 4 and >> month(from_unixtime(archive_day_rain.datetime)) <= 9 and >> archive_day_rain.datetime=archive_day_ET.datetime; >> >> What I am doing right now, is running a crontab job, and start my >> PHP-script every minute to calculate the outcome of the SQL-script above >> and writes the outcome to a plan txt-file. Next step is to grab this value >> from the txt-file and show it (javascript) on my website. See >> http://www.weerinwelsum.nl, below the webcam. It says ' Doorlopend >> neerslagtekort', [amount of millimeters]. This is the value I am talking >> about. >> >> What I really want to achieve, is that I calculate this derived valu by >> WeeWX itself, and make this derived value available for everything that's >> wants to use is. For example, store this derived value in a database-field >> I am not using (for example, soilTemp4) and make this derived value >> available for whatever skin (in my case, Belchertown). In other words, >> Weewx calculates this new value and makes it available for the complete >> WeeWX-ecosystem (if you understand what I mean). >> >> Am I clear in what I want to achieve? And is this possible, and what are >> the pointers to do so? >> >> -- >> 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...@googlegroups.com <javascript:>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/weewx-user/d48cfc39-5e17-4795-a75f-ac4c266e73b0%40googlegroups.com >> >> <https://groups.google.com/d/msgid/weewx-user/d48cfc39-5e17-4795-a75f-ac4c266e73b0%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> >
-- 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/550c4e0a-fad5-4169-bb3a-cc530f383a55%40googlegroups.com.
