12 steps an hour

[opticsman0127]

Been using exclusively Cumulus now for a couple of weeks. It's excellent, runs a treat. However, I am pretty sure that I have got something set up wrong which is not showing off its true capabilities though. As an example, the pressure graph displayed here http://www.barrypemb.f2s.com/trends.htm is far more detailed than the wind graph at same URL. I have the logging interval set at 5 mins and the 10 min average box unchecked. Attached screenshot of set up display.
Have I set up something wrong or, does the wind graph plot every logging interval of 5 mins, 12 per hour?

Any guidance appreciated.

Barry

[steve]

Wind speed is plotted once a minute, the same as everything else. I suspect the reason for the lack of change on your 'speed' plot is simply that your wind speed is low and the 10-minute average isn't changing much (given the 1 mph resolution of Davis stations).

For the 'gust' plot, you can tick 'plot latest gust' in the Graphs section of the Display settings, and Cumulus will then plot the current value of the 3-second speed read from the station, and this should in theory vary more often than the 'peak 10-minute' value that it plots by default. Note that if you do this your 'gust' line will sometimes be above the average and sometimes below, which confuses some people as they expect a "gust" to always be higher than the average. This happens because the Davis stations don't actually supply a 'gust' figure in the sense of a peak value, which is why the default is to plot the peak from the last 10 minutes.

[opticsman0127]

Sounds logical. Will pray for a little more wind to check out the theory. Will also set the 'plot latest gust' later this morning and post results.

Thanks for suggestions.

Barry

[opticsman0127]

Steve,

See what you mean about the gust, it does need a bit of thought to relate to the gust dropping below average but, the maths support that.
OK on the resolution of the wind speed is 1mph with the Davis. So, on software like WD, are they just applying smoothing to the graphs, it appears so.
One aspect of Cumulus resolution; the inside and outside temps seem to have either a different resolution or different plotting features, the 'inside' seems very stepped compared with 'outside' or, have I got a setting wrong here too?

Barry

[mcrossley]

One aspect of Cumulus resolution; the inside and outside temps seem to have either a different resolution or different plotting features, the 'inside' seems very stepped compared with 'outside' or, have I got a setting wrong here too?

It's just that the graph range for the internal temp is much smaller than the external, so you can see the measurement quanta. Switch your heating off and leave the windows open for the day, then it will look a lot smoother!

[opticsman0127]

Cheers Mark,

[opticsman0127]

Just had a quick tour round a few sites. One near me http://www.nelsonm.plus.com/weather/trends.htm shows a great deal of resolution in the wind speed. Something must be wrong with my settings.

Another http://sixtownsweather.dyndns.org/trends.htm another http://sandaysoft.com/maps/cumulus-map.php there are dozens showing far higher resolution

Barry

[steve]

They don't have Davis stations.

[opticsman0127]

Excellent reason!

[opticsman0127]

Could it be that these stations may have got wrong equipment listed?

http://www.hosiene.co.uk/weather/cumulus/trends.htm Varying degrees of resolution
http://www.bramptonweather.co.uk/cumulus/ Looks to be higher resolution than mine but wider time scale
http://carnbreaweatherstation.co.uk/weather/ Exactly what I am looking for on wind

Barry

[steve]

The Vantage Pro 2 has a wind speed resolution of 1 mph. I can't change that.

Those stations are plotting to a resolution of 1 mph. Two of them are plotting knots. Two of them have 'plot latest gust' selected, hence the plotted value changes more frequently; the other one is plotting a period of 48 hours, so the 'steps' appear smaller.

If a Davis site is showing average wind speeds at a smaller resolution that 1 mph, it's because they have Cumulus calculating the average, and they haven't selected the option to not show decimal places, which they really should do, as otherwise they are claiming unwarranted accuracy.

[opticsman0127]

Steve,

i thouight I followed all this but there is something which, if I am understanding it correctly, conflicts with your comments. If the Davis only registers wind speed to 1mph, how is Cumulus recording on the wind dial regularly wind speeds to an naccuracy of 0.1mph but only recording to 1mph scale? See attachment

Barry

[steve]

It appears that you've set a 'gust' multiplier of 1.2.

[opticsman0127]

Thanks Steve. You are correct, it is set at x1.2. Unable to check at the moment but, does Cumulus plot the wind coming from the Davis or, after the x1.2 factor is applied.

[mcrossley]

After the factor is applied. Note also that the gauge component only seems to display to integer values.