For the loop packets this is what I already thought to know. What I wanted to know if my weew archive interval is 5 mins, and the hardware stored at 1min: Lets assume the archive_interval 11:05:00am to 11:10:00am is to be backfilled. The driver gets the stored archive values from the hardware, where the maxvalue was at 11:07:00am. Is the maxvalue in the archive_day_xxx table for that day timestamped with 11:07:00am or with 11:10:00am?
gjr80 schrieb am Dienstag, 9. Februar 2021 um 13:11:41 UTC+1: > If your one loop packet was the only loop packet received by WeeWX in that > archive interval then the archive record that WeeWX would synthesise from > that solitary loop packet would be the same as that loop packet. If as you > said that loop packet was stored by hardware and if the driver's > genArchiveRecord() method obtains that same data when it generates an > archive record, then yes they will be the same. Highs and lows in the daily > summaries would be the same but it would not surprise me if some timestamps > were different. Loop packets are generally timestamped when the data is > read, whereas archive records are typically timestamped at the end of the > period they cover. So for an archive interval that covers say 11:05:00am to > 11:06:00am, the loop packet may have been created at 11:05:25am and > timestamped accordingly. If WeeWX is set to obtain highs and lows from loop > packets (ie loop_hilo <http://weewx.com/docs/usersguide.htm#StdArchive> > is True) then if a new max/min is found in that loop packet the relevant > timestamp recorded in the daily summary will be the loop packet timestamp. > If you now consider the archive record that is read during a backfill, it > will be timestamped 11:06:00am, again any new highs or lows will be > recorded (so the actual aggregate value will be the same) but in this case > the timestamp recorded for the high or low will be the archive record > timestamp 11:06:00am. If you happen to have more than one loop packet in > the archive period then you may loose some fidelity of the actual > observation high/low value as well. > > This is the same effect you see if you rebuild your daily summaries with > wee_database > --rebuild-daily, if you have loop_hilo = True then your daily summary > tables will likely have loop packet timestamps for many highs and lows but > after you rebuild the daily summaries you loose that fine detail and your > high/low timestamps will align with archive record timestamps. If you have > multiple loop packets in an archive interval then your high/low values may > be one of the values in those loop packets, after rebuilding though you end > up with archive values being used to generate the highs and lows which are > typically averages of loop values. For example, if you have four loop > packets in an archive interval and each has an outTemp value of 8.0, 9.0, > 12.0 and 7.0 degrees C your daily summary may record 12.0 as the max. The > corresponding archive record outTemp value would (8.0+9.0+12.0+7.0)/4=9.0 > so your max might be 9.0. > > Gary > > On Tuesday, 9 February 2021 at 21:03:10 UTC+10 [email protected] wrote: > >> > If you mean does WeeWX determine if any incoming archive record has >> (for example) a new daily max for some field and then save that data, then >> yes that is what StdArchive does. >> >> So if a hardware sends a loop packet with all the readings in a >> one-minute-interval, and stores these exact values in its own storage in a >> separate entry, one entry per minute, the weewx database values are exactly >> the same, regardless if they were received as loop data as if they were >> backfilled? Including timestamps and Values for min/max in >> archive_day_xxxx, which may differ from the min/max value found in all >> weewx archive records of that particular day, with timestamps between >> possible timestamps of archve values? >> >> -- You received this message because you are subscribed to the Google Groups "weewx-development" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/weewx-development/83e6a266-ad60-484f-a0d1-a55d6c89ef37n%40googlegroups.com.
