Hi,

Perhaps a small insight into the operation of the image generator might 
help. Yes it is true that at the end of each archive period (during the 
report generation cycle) the plots are copied to public_html (or wherever 
you have set them to be copied). However, it is not quite as simple as 
that, what is really going on is only those plots that have been generated 
are copied. As you have found out the aggregate_interval has a role in how 
often/when images are generated, in fact all other things being equal plots 
are generated every aggregate_interval seconds. If no aggregate interval is 
specified then they are generated every report cycle.

So you might say well why not have a very small or zero aggregate interval 
for each plot, you can certainly do that but there is a penalty to pay. 
When WeeWX generates a plot it queries the archive and obtains all of the 
data points for the observations required over the period of the plot. In 
the case of a day plot the period covered is 27 hours so assuming a 5 
minute archive interval WeeWX would use 27x12=324 data points per 
observation. These points are then plotted. For a week plot we now have 
7x24x12=2016 points, a month we have (approx) 31x24*12=8928 and for a year 
we have 105120 data points. Now WeeWX will quite happily plot 324 data 
points, as it will 2016 but when we get to 8928 and 105120 it takes WeeWX a 
very long time to generate the plots (remember there are numerous plots 
each with (usually) multiple obs each with 8928/105120 data points. So the 
way WeeWX mitigates this load is to reduce the number of points being 
plotted by using an aggregation, say the average over 1 hour (for month 
plots) and over 1 day for year plots. This brings us down to around 744 
points for a month and 365 points for a year, much more manageable and 
comparable to day and week plots. The load on the processor is further 
reduced by only re-generating the plots after their aggregate_interval has 
passed.

So what, well as I said you can certainly reduce the aggregate interval to 
60 and all plots will then be generated every report cycle. But if you have 
a look at your logs you will probably find the time taken to produce your 
reports has increased significantly. This may or may not be a problem 
depending on your archive interval and your processor. But if your reports 
are taking close to your archive period to complete you may find your 
system will become unstable or some report cycles may be skipped - quite 
the contrary to what you are trying to achieve. Also remember that on a 1 
year plot with say 105120 points I don't think you will really be able to 
see the difference 1 extra point makes so really you are gaining very 
little by running a long period report every report cycle with a very small 
or zero aggregate interval.

I hope that helps explain what your are seeing, why you are seeing it and 
the possible consequences of your changes.

Gary

On Friday, 22 February 2019 04:59:25 UTC+10, Henry Denston wrote:
>
> Ok, after hours of trial and error I guess the lable 'aggregate_interval' 
> is responsible for my issue.
> I set it to 60 (so Images/Plots will get copied when older than a minute 
> everytime a record runs).
>

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