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Forecast Trend Displays

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    Forecast Trend Displays

    V3.4.0 contains a proof-of-concept implementation for generation and display of what amounts to the first derivative of the barometer, humidity, and rain measurements. Only the baro rate/trend is included in the Forecast.asp page at this time.

    A new Weather sensor type, barometer rate, should be detected if a barometer sensor is installed. The value in the virtual device and database will show the rate of change for any two consecutive samples which change in the same direction. The magnitude of the value will be delta change over the last three samples. Values of zero will be used in all other cases.

    I suspect the algorithm may be too sensitive and some additional filtering can be applied. The downside to filtering, however, is responsiveness. Anyone with barometer data will need to do some empirical analysis to look at the short term response of the barometer sensor, especially as weather fronts move in.

    A 10 pixel by 10 pixel arrow icon is included on the Forecast.asp page to the right of the barometer reading. The height of this arrow (from 0 to 10 pixels) is computed as the sensitivy scale * barometer rate. A very large value entered on the Forecast tab of the setup page will cause the arrow to toggle between full scale and zero. Smaller sensitivy values will allow the arrow to scale based upon the rate at which the barometer is changing. This is again emperical to achieve the desired effect.

    The icon used is a simple arrow with poor contrast so scaling in a 10 pixel range is not very effective visually. I would like to maintain compatibility with 640x480 screens, but some improvement in the display is needed and suggestions solicited.

    The same approach is inteded for the humidity and rain. Currently the rain rate is shown numerically with the intent of it being replaced by a scaled icon similiar to what is being investigated for the baro. The humidity display contains provisions for both an indoor and outdoor reading on the Forecast.asp page. It is the intention to allow either a second reading or the trend arrow on the first to be shown.

    Since I asked for this, I'll be giving you some feedback. However .... I've managed to break my Barometer at the moment and I'm waiting on JJ to send me some IC's by post. Should only be a few days.

    Just didn'r want you to think I ask for things then ignore them