Tom, First of all let's consider solely the data fields wee_import can obatin from WU and the Cumulus monthly log files. When we import from WU we cannot obtain inside temperature, inside humidity and rain rate so if those fields are populated in your Cumulus data you would lose that data if you import from WU (WU does not provide UV but you said you do not have that sensor so no loss of data there). There are also a couple of other differences (apparent temperature, wind chill, heat index and rain rate) that WU does not provide but these are derived observations that wee_import can calculate. You will find more info on what fields wee_import can import from WU and Cumulus in the Utilities Guide here <http://weewx.com/docs/utilities.htm#Importing_from_Weather_Underground> and here <http://weewx.com/docs/utilities.htm#Mapping_data_to_archive_fields51> respectively.
The other issue is the integrity of the data source being used. Importing from WU requires wee_import to submit a http WXDailySummary request to obtain one days data at time. This may or may not return all data for the day, in fact if you run a wunderfixer session for a given day (wunderfixer uses the same http call to get a given day's data from WU) say 10 times, the number of records returned by WU will almost certainly vary across some of the runs. This effect can be offset to some degree by running the import multiple times, but at the end of the day unless you check each days records you cannot be sure you have them all. Equally there can be integrity issues with the Cumulus monthly log files for any number of reasons, but on the whole I have found them to be more reliable than WU. Still along data integrity lines, WU requires the weather station software to submit data via the internet, weeWX is fortunate to have wunderfixer to catch up on any WU records that may have been lost if the internet was unavailable for some reason. I am not sure if Cumulus has such a mechanism and if not there may well be some holes in the WU data if you have had any internet outages. If your Cumulus data is compete and you have no reason to doubt it I would use your Cumulus data in prefernce to WU. If for some reason you have a gap in your Cumulus data but it exists on WU, then you might consider importing the Cumulus data and then just that missing data from WU (wee_import does allow you to limit by date-time what data is imported). I defintely would not import from both for any given time period as all you will need is a 1 second difference in timestamp and you could end up with 2 records, largely the same but separated by a very small number of seconds which could well skew some of your aggregates. Hope this helps. Gary On Sunday, 14 January 2018 09:02:29 UTC+10, T Konzl wrote: > > Hello everyone, > > I searched the group for this information, but couldn't find anything > related. My question: is there any advantage of importing WU over default > (out-of-the-box) Cumulus data?...specifically in regard to data > completeness? Do any additional fields get populated from either the > Cumulus data or WU data vs the other? I suppose it depends on the PWS. I > have a Davis VantageVue ISS, so no solar or other fancy sensors. > > I'm at a point where I'm ready to continue importing to weeWX and have > both Cumulus and WU data for 2016 & 2017, and want to know which is > preferred to upload and why. > > Thank you, > > Tom K. > -- 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. For more options, visit https://groups.google.com/d/optout.
