[rrd-users] Trend to show cloud height -Weather Station Application

[Robert Conway]

Hi,

I want to create a trend which shows the height of clouds for my weather
station.  (Approx cloud height is a calculation from pressure and humidity)
Instead of shading the area under graph value I want to shade above the
value up to 100% of scale in a sky blue.  I was going to simply use a CDEF
to calculate the diff between actual value and 100% of scale and trend this
via a stack.  My question is that the real value I want to be totally
transparent so I only see the sky blue colour in the upper part of the
trend.    

 

Is there a hex colour value for totally transparent ?

 

It would be really cool if the upper "sky" blue area of the graph actually
shows some random white clouds within this area so it really looks like sky.
I don't know if I could achieve this via a CDEF anybody have any idea's of
how I could achieve a cloud shape object within this upper area randomly
within the time line. I assume its again a stack command however really need
it as a random shape "cloud looking".  An alternative maybe to simply
generate the graph then use imagemagic to insert clouds within the upper
graph area.

 

Any idea's

 

Cheers

 

Rob Australia

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