Need some help changing a chart

[Steve2Q]

Hi all. I have not been on since BC (before Covid). I want to change my windspeed chart, but so far (because I forgot what my initial change was), I have not been successful. Here is what I would like to do;

Presently my windspeed chart looks like the attached. I thought I was being clever at the time by adding what I thought was windgust, but this was incorrect as my console (Peet Bros) only sends wind speed. I also added average windspeed. As you can see, the actual windspeed (blue) is labeled Gust Speed while the incorrect windgust (black) is labeled Wind Speed. What I want to do is get rid of the windgust completely and have the true wind speed labeled properly. I also want to keep the average windspeed as that calculation appears correct.

The following snip is from my skin.conf file:

 #        time_length = 43200
   #  Removed # on following 5/8/18 Switched order of WindSpeed and WindGust
              [[[[windGust]]]]
                color = 'blue'
                anti_alias = 2
   #  Changed color and data_type
              [[[[wind_avg]]]]
                color = 'yellow'
                data_type = windSpeed
                aggregate_type = avg
                aggregate_interval = 3600    # 1 Hour
                line_gap_fraction = 0.05
                label =  1 Hour Avg Speed
   #  End of addition
               [[[[windSpeed]]]]
                color = 0x000000
                anti_alias = 2

Thanks for any help..

[gjr80]

Steve,

So have you tried:

 #        time_length = 43200

   #  Changed color and data_type
              [[[[wind_avg]]]]
                color = 'yellow'
                data_type = windSpeed
                aggregate_type = avg
                aggregate_interval = 3600    # 1 Hour
                line_gap_fraction = 0.05
                label =  1 Hour Avg Speed
   #  End of addition
               [[[[windSpeed]]]]
                color = 0x000000
                anti_alias = 2

That will plot windSpeed (black) and the one hour average windSpeed (yellow) values. Keep in mind that for your system the windSpeed value in each archive record is the average of all of the loop packet windSpeed values seen in that archive period. So if your station sees a windSpeed of, say 20mph, in a single loop packet that value well be 'lost' when all of the loop packet windSpeed values are averaged to give the windSpeed value for the archive period (chances are the average will be less than the maximum value) - so don't expect the max wind speeds seen by your station to be appear on the modified plot. The default action by WeeWX when no windGust is provided by the station/driver is to use the highest windSpeed value seen during the archive period as the windGust value in the archive record. Another way of looking at it is to think of the labelling of your current plot as 'Gust Speed    1 Hour Avg Speed    5 Minute Avg Speed' (assuming you have a five minute archive interval).

Gary

[Steve2Q]

Hi Gary. I did not get to try your suggestions until today. We went on a 3 week cruise, but when I got home I ended up with Covid. Not a very bad case, but I am just now getting my act together.

Just a few comments:

1. I made your suggested change by commenting out the lines pertaining to wind gust, but I want to wait until I see a full days plot before making any other changes. One thing I do see is that the 1 Hour Average Speed is showing as dots rather than a continuous line as before. Does that mean the LineGap fraction has to be changed?

2. Regarding the windspeed v windgust differences you mention. I have a Peet Bros Ultimeter, so the windspeed (along with the other parameters) is emitted nearly constantly. My archive interval is 2 minutes, while the Loops are approx every 2 seconds. I noticed that when I had windgust included in the plot, it appeared to more accurately reflect the "High Wind" reading under "Since Midnight" on the Current Conditions page. Is it possible to have windgust plotted while having the chart label as windspeed?

I just want to say thank you for all the help you have given me over the past few years...it is greatly appreciated

[gjr80]

Hi Steve, sorry to hear about COVID, hope you get over that quickly,

I need to refresh my memory on line_gap_fraction, from memory on a 27 hour plot with line_gap_fraction = 0.05 you should only see gaps when the dots are >81 minutes apart. You could try removing the line_gap_fraction setting by commenting it out.

Just to refresh what WeeWX does with your station wind speed data. Whilst your station does feed wind speed every two seconds to WeeWX, the WeeWX field windSpeed is calculated as the average of all of those loop wind speed values over a two minute archive period. So if you plot windSpeed you will loose visibility of those 'highs' as those two second wind speed values are averaged. WeeWX will calculate the WeeWX field windGust as the maximum loop wind speed value seen over a two minute archive period. So if you want to see those wind speed 'highs' you are going to need to include windGust somehow in your plots. The out of-the-box wind speed plot from WeeWX plots both windSpeed and windGust, this gives the characteristic two line plot where windSpeed is the 'lower' plot line and windGust is the 'upper' plot line. Some folks don't like the inherent averaging that the windSpeed plot uses and they want to see the 'highs' so they remove windSpeed from the plot and just plot windGust. I expect some do other things like plotting various aggregates. Myself, I like to see both windSpeed and windGust as it gives me an indication of 'peakiness' of the wind as well as the 'steady state' wind speed.

You can easily change the label for any plot, just use the label option (as above for the [[[wind_avg]]] plot).

Also, no need to wait for a day to see your changes, just delete the corresponding plot file from your WeeWX machine and it will be regenerated on the next report cycle.

Gary

[Steve2Q]

Hi Gary. Thanks for the good wishes. I tested negative this AM. I played around for a while, and decided that WindGust would show me what I wanted on the chart; agreement with the daily High Wind under Since Midnight. I also had the epiphany (at least it was for me because I did it before reading you message!) that I could just chart WindGust but label it Wind Speed. So here is a screen grab of the chart where the high wind speed since midnight is 11mph at 1644: