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weewx-GTS

XType extension for WeeWX to provide

"Grünlandtemperatursumme" (a kind of growing degree days)
observation types 'dayET' and 'ET24' as the opposite to 'dayRain' and 'rain24'
observation types for equivalent (potential) temperature, mixing ratio, absolute humidity, and (saturation) vapor power
additional aggregation type for 'radiation' to calculate the total energy received during the aggregation interval
tags for day boundaries other than midnight local timezone time
observation types 'yearGDD' and 'seasonGDD'
aggregation type 'GDD'

Creating issues

If you want to report bugs or need help, please, refer to Help! Posting to weewx user for instructions. It applies here, too.

Please note, that GTS and yearGDD require temperature data from January 1st on to be calculated. If your database does not cover the whole timespan, those values cannot be calculated. You will have to wait for the next year.

If skin creation lasts too long for you, please, read the WeeWX wiki article XTypes performance first before creating an issue here. We can try to optimize things, but we cannot do magic.

Installation instructions:

download

wget -O weewx-GTS.zip https://github.com/roe-dl/weewx-GTS/archive/master.zip

run the installer

WeeWX up to version 4.X
```
sudo wee_extension --install weewx-GTS.zip
```
WeeWX from version 5.0 on and WeeWX packet installation
```
sudo weectl extension install weewx-GTS.zip
```
WeeWX from version 5.0 on and WeeWX pip installation into an virtual environment
```
source ~/weewx-venv/bin/activate
weectl extension install weewx-GTS.zip
```

check configuration in weewx.conf

[StdWXCalculate]
    [[Calculations]]
        ...
        GTS = software,archive
        GTSdate = software, archive
        utcoffsetLMT = software, archive
        dayET = prefer_hardware, archive
        ET24 = prefer_hardware, archive
        yearGDD = software, archive
        seasonGDD = software, archive
        outVaporP = software,loop
        outSVP    = software,loop
        outMixingRatio = software,loop
        outEquiTemp = software,loop
        outThetaE = software,loop
        outHumAbs = software,loop
...
[Engine]
    [[Services]]
        ...
        xtype_services = ... ,user.GTS.GTSService

restart weewx

for SysVinit systems:

sudo /etc/init.d/weewx stop
sudo /etc/init.d/weewx start

for systemd systems:

sudo systemctl stop weewx
sudo systemctl start weewx

Including in skins:

You can use the values provided by this extensions in all skins of WeeWX. You can show the values, and you can create a diagram. The following observation types are provided:

Grünlandtemperatursumme

"Grünlandtemperatursumme" is a kind of growing degree days that is used to estimate the start of growing of the plants. For the algorithm see below.

Display values (CheetahGenerator)

GTS: the value of "Grünlandtemperatursumme" itself (example tag: $current.GTS)
GTSdate: the date when the GTS value exceeds 200, which is considered the beginning of real spring (example tag: $day.GTSdate.last.format("%Y-%m-%d"))
utcoffsetLMT: offfset of the local mean time (Ortszeit) at the station's location
LMTtime: a string showing the local mean time (Ortszeit) at the station's location (can only be used with ".raw", example tag: $current.LMTtime.raw)

The values can be used together with every time period defined in the customization guide of WeeWX. There can be used aggregations as well. The following aggregations are defined: avg, min, max, last, has_data, not_null. Not all time spans are possible.

See http://weewx.com/docs/customizing.htm#Tags for details on how to use tags in skins.

Caution: The aggregation exists only reports whether the observation type is included in the database or not. For pure XTypes like the observation types provided here it reports False. The behavior of has_data changed. It reports False for WeeWX up to version 4.10 and True for WeeWX from version 5.0 on.

Diagrams (ImageGenerator)

To create diagrams you need to include additional sections into the [ImageGenerator] section of skin.conf. What follows are examples. There are more possibilities than that.

Within [[month_images]]:

        [[[monthGTS]]]
            line_gap_fraction = 0.04
            yscale = 0,None,None
            aggregate_type = avg
            [[[[GTS]]]]
                aggregate_interval = 86400
                label = Grünlandtemperatursumme

Within [[year_images]]:

        [[[yearGTS]]]
            aggregate_type = avg
            [[[[GTS]]]]
                label = Grünlandtemperatursumme

These examples create image files named 'monthGTS.png' or 'yearGTS.png', respectively. To display them within the web page appropriate <img> tags need to be included for example in index.html.tmpl:

<img src="monthGTS.png" />

<img src="yearGTS.png" />

Diagrams (WDC skin)

see Using weewx-GTS in WDC wiki

Diagrams (Belchertown skin)

configuration in graphs.conf:

    [[Vegetation]]
        #title = "Gr&uuml;nlandtemperatursumme"
        title = "Vegetation"
        aggregate_type = avg
        yAxis_label = "Wachstumsgradtage"
        yAxis_softMin = 100
        yAxis_softMax = 200
        exporting = 1
        [[[GTS]]]
            observation_type = GTS
            name = "Gr&uuml;nlandtemperatursumme"
        [[[yearGDD]]]
            observation_type = yearGDD
            name = "Wachstumsgradtage"
        [[[seasonGDD]]]
            observation_type = seasonGDD
            name = "Wachstumsgradtage Saison"

Growing degree days

Display values (CheetahGenerator)

yearGDD: the sum or integral of growing degrees from the beginning of the actual year up to the current time
seasonGDD: the sum or integral of growing degrees from GTSdate up to the current time. Before GTSdate the value is undefined. After October 31st it is undefined, too.
aggregation type GDD (or growdeg): Used to calculate growing degree days for observation types other than outTemp. This can be every temperature value, say greenhouse temperature.

Diagrams (ImageGenerator)

Within [[year_images]]:

        [[[yearGDD]]]
            aggregate_type = avg
            [[[[yearGDD]]]]
                label = Growing degree days
            [[[[seasonGDD]]]]
                label = Season growing degree days

This example creates an image files named 'yearGDD.png'. To display it within the web page appropriate <img> tags need to be included for example in index.html.tmpl:

<img src="yearGDD.png" />

You can combine that with GTS:

        [[[yearGTS]]]
            aggregate_type = avg
            [[[[GTS]]]]
                label = Grünlandtemperatursumme
            [[[[yearGDD]]]]
                label = Growing degree days
            [[[[seasonGDD]]]]
                label = Season growing degree days

To display it within the web page include the appropriate <img> tag for example into index.html.tmpl:

<img src="yearGTS.png" />

Diagrams (WDC skin)

see Using weewx-GTS in WDC wiki

Diagrams (Belchertown skin)

see above

Evapotranspiration

Display values (CheetahGenerator)

dayET: the sum of ET from the beginning of the archive day on, like dayRain does for rain
ET24: the sum of ET over the last 24 hours, like rain24 does for rain

Diagrams (ImageGenerator)

dayET and ET24 are not used in plots.

Special derived meteorological readings

WeeWX already includes the calculation of some special derived meteorological readings, but they are used internally, only. This extension makes them available for use in section [StdWXCalculate] and in tags.

Please note: WeeWX comes with an example extension, that calculates a value called "vapor pressure", but it is in fact saturation vapor pressure. The example uses another algorithm than WeeWX internally.

Caution: The calculation of these values is alpha code. It needs to be evaluated.

Display values (CheetahGenerator)

outSVP: saturation vapor pressure
outVaporP: actual vapor pressure
outMixingRatio: mixing ratio
outHumAbs: absolute humidity
outEquiTemp: equivalent temperature
outThetaE: equivalent potential temperature
boilingTemp: boiling temperature depending on station altitude and actual air pressure

Diagrams (ImageGenerator)

To show diagrams of these readings there is no need to store them in database. They will be calculated "on the fly" by the XTYPE system of WeeWX.

Example: absolute humidity

        [[[dayhumabs]]]
            unit = gram_per_meter_cubed
            [[[[outHumAbs]]]]

Diagrams (Belchertown skin)

Example: Display both the relative and absolute humidity in one diagram

    [[humidity]]
        title = "Humidity"
        [[[outHumidity]]]
            name = "relative
        [[[outHumAbs]]]
            name = "absolute"
            yAxis = 1
            unit = gram_per_meter_cubed
            [[[[numberFormat]]]]
                decimals = 1

Radiation energy

'radiation' and 'maxSolarRad' are built-in observation types of WeeWX. This extension only provides an additional aggregation type to them. It is called 'energy_integral' and calculates the total energy received during the aggregation interval.

Note: An Integral is not a sum of observation readings. See below for algorithm.

Display values (CheetahGenerator)

You need to use this aggregation type together with aggregation timespans like $day, $yesterday, $week, $month, and $year as well as timespans defined by some other extension to WeeWX.

energy_integral can be used like any other aggregation type like min, max, or sum.

Example: $yesterday.radiation.energy_integral displays the total sun energy received the day before.

To display the value in kWh/m^2 instead of Wh/m^2 use: $yesterday.radiation.energy_integral.kilowatt_hour_per_meter_squared

Diagrams (ImageGenerator)

Within [[month_images]]:

        [[[monthRadiationEnergy]]]
            line_gap_fraction = 0.04
            #y_label = "Wh/m²"
            [[[[radiation]]]]
                label = "Sonnenenergie (täglich gesamt)"
                data_type = radiation
                aggregate_type = energy_integral
                aggregate_interval = 86400

This example creates an image file called 'monthRadiationEnergy.png' To display it within the web page an appropriate <img> tag needs to be included for example in index.html.tmpl:

<img src="monthRadiationEnergy.png" />

Diagrams (Belchertown skin)

Belchertown skin uses another plot engine (Highcharts). Therefore the syntax is slightly different.

In section [month] or [year] of graphs.conf:

    [[Sonnenenergie]]
        title = "Sonnenenergie (täglich gesamt)"
        aggregate_type = energy_integral
        aggregate_interval = 86400
        yAxis_label = Energie
        yAxis_label_unit = "Wh/m&sup2;"
        [[[radiation]]]

No <img> tag is needed.

NOAA-like Table

There is an example template to create a text file showing monthly summeries of sun energy and sun radiation in the examples directory. To use it, copy the file to your skin directory and add the following to your skin.conf:

[CheetahGenerator]
    ...
    [[SummaryByYear]]
        ...
        [[[sun_year]]]
            encoding = strict_ascii
            template = sun-%Y.txt.tmpl

This creates a file for every year that data is available for.

Soil moisture

For soil moisture WeeWX defines the unit group group_moisture using the unit centibar. This presumably refers to the Davis Instruments soil moisture/temperature station 6345, which strictly speaking does not measure moisture but suction pressure.

Sometimes this pressure is expressed in a logarithmic value called pF value. This extension provides the pF value as an additional unit to group_moisture, called pF_value. It makes other pressure units than centibar available to group_moisture, too.

Special time spans

Sometimes day span used in meteorology are not from midnight to midnight but start and end at some arbitrary time of day like 09:00 a.m. To aggregate values with day boundaries other than midnight the following tags are provided. They are used like standard $hour, $day etc.

Arbitrary offset to UTC

$offsethour(data_binding=None, hours_ago=0, dayboundary=None)
$offsetday(data_binding=None, days_ago=0, dayboundary=None)
$offsetyesterday(data_binding=None, dayboundary=None)
$offsetmonth(data_binding=None, months_ago=0, dayboundary=None)
$offsetyear(data_binding=None, years_ago=0, dayboundary=None)

dayboundary is an offset to UTC in seconds, that sets the time of day to use as the day boundary for the given aggregation. In case of Python <3.7 the value is rounded to whole minutes.

Local Mean Time of the station location

$LMThour(data_binding=None, hours_ago=0)
$LMTday(data_binding=None, days_ago=0)
$LMTyesterday(data_binding=None)
$LMTmonth(data_binding=None, months_ago=0)
$LMTyear(data_binding=None, years_ago=0, month_span=None)

Day boundary is midnight Local Mean Time which is always near the antitransit of the sun at the station's location.

The optional parameter month_span is a time span of several months within the given year. For example $LMTyear(month_span=(6,8)).outTemp.avg is the average temperature of the summer of the actual year. $LMTyear(years_ago=1,month_span=(12,2)).outTemp.max is the maximum temparature of the last winter season.

The attribute days can be used together with $LMTmonth and $LMTyear for iteration.

Daylight timespan

$daylight(timestamp=None, data_binding=None, days_ago=0, horizon=None, use_center=False)

timespan from sunrise to sunset

If timestamp is None (the default), it is the timespan from sunrise to sunset of the current day or the day days_ago days ago.

Otherwise timestamp can be a class TimespanBinder, a timespan or a timestamp. $daylight is then the timespan between sunrise and sunset of the day the specified timespan or timestamp is in. This is useful in #for loops over days.
$LMTweek(data_binding=None, months_ago=0).daylights(horizon=None, use_center=False)

series of timespans describing the timespan from sunrise to sunset for each individual day. For use in #for loops
$LMTmonth(data_binding=None, months_ago=0).daylights(horizon=None, use_center=False)

series of timespans describing the timespan from sunrise to sunset for each individual day. For use in #for loops
$LMTyear(data_binding=None, months_ago=0).daylights(horizon=None, use_center=False)

series of timespans describing the timespan from sunrise to sunset for each individual day. For use in #for loops

For the options horizon and use_center see WeeWX customization guide. If omitted, defaults are used.

Examples:

average temperature while the sun is up
```
$daylight.outTemp.avg
```

table with day of month and the average temperature while the sun is up on that day

#for $span in $LMTmonth.daylights
<p>$span.dateTime.format("%d"): $span.outTemp.avg</p>
#end for

rain during day and night of the days of the current week

#from weewx.units import ValueTuple, ValueHelper
<table>
<tr>
<th>Day</th>
<th>Day rain</th>
<th>Night rain</th>
</tr>
#for $dd in $week.days
#set $light=$daylight(timestamp=$dd)
#set $nightrain=$dd.rain.sum.raw-$light.rain.sum.raw
#set $nightrain_vh=ValueHelper(ValueTuple($nightrain,$unit.unit_type.rain,'group_rain'),formatter=$station.formatter)
<tr>
<td>$dd.start.format("%Y-%m-%d")</td>
<td>$light.rain.sum</td>
<td>$nightrain_vh</td>
</tr>
#end for
</table>

sunrise, sunset, and duration of daylight using the timestamp option

<table>
<tr>
  <th>sunrise</th>
  <th>sunset</th>
  <th>daylight</th>
</tr>
#for $dd in $week.days
<tr>
  <td>$dd.format("%A")</td>
  <td>$daylight(timestamp=$dd).start</td>
  <td>$daylight(timestamp=$dd).end</td>
  <td>$daylight(timestamp=$dd).length</td>
</tr>
#end for
</table>

Algorithm:

Grünlandtemperatursumme (GTS)

GTS is calculated from the daily average temperatures. If the daily average temperature is above 0°C (32°F) it is used to add to the sum, otherwise it is discarded.
In January the daily average temperatures are multiplied by 0.5.
In February the daily average temperatures are multiplied by 0.75.
From March on the daily average temperatures are used as is.
To get the GTS value of a day all the values as described above are added from January 1st to the day in question. So the GTS value increases in time.
If the GTS value exceeds 200 this event is considered the beginning of growing of the plants in spring.
The GTS value itself is calculated up to May 31st. The end value is considered a statement about the spring.

Radiation energy

Radiation energy is calculated as follows: All the radiation readings within the aggregation interval are multiplied by their respective archive interval. That is based on the assumption that the radiation was constant during that interval. The error resulting form that is considered small enough to tolerate.

After that all the products of radiation and time interval are summarized together.

While the unit label of the radiation reading is W/m^2, the unit label of the radiation energy is Wh/m^2.

Daylight timespan

The $daylight tag uses the built-in module of WeeWX that provides the $almanac tag.

While $almanac.sunrise and $almanac.sunset calculate sunrise and sunset using the actual temperature and barometer of the calculation time, $daylight observes temperature and barometer of the time, the daylight timespan is calculated for if there are database records available. It first calculates approximate sunrise and sunset times for the ICAO standard atmosphere at 15°C and 1013.25 mbar. Then it looks up the real temperature and barometer for both those times. After that it calculates sunrise and sunset again, using the respective temperature and barometer.

That's why $daylight(timestamp=$X).start provides a more accurate time for sunrise than $almanac(timestamp=$X).sunrise if $X is a timestamp somewhere in the past and database records are available for that time. The same applies to $daylight(timestamp=$X).end instead of $almanac(almanac_time=$X).sunset for sunset and $daylight(timestamp=$X).length instead of $almanac(almanac_time=$X).sun.visible for the daylight duration.

Barometer

WeeWX includes several algorithms to calculate the barometer value out of the station pressure. Unfortunately those algorithms are not available to the user by default. And by 2023 there is no way to pass parameters to an XType. The barometer extension does a little bit of that and allows to add an algorithm name to the observation type barometer. This allows the following observation types:

barometerManBar
barometerDavisVp
barometerUnivie
barometerDWD

This is a temporary workaround only. It will be removed when WeeWX fully implements parameters to observation types.

Sources:

http://www.groitzsch-wetter.de/HP/green1.html
http://www.regionalwetter-sa.de/sa_gruenland.php
WeeWX examples/stats.py

hoetzgit/weewx-GTS

weewx-GTS

Creating issues

Installation instructions:

Including in skins:

Grünlandtemperatursumme

Display values (CheetahGenerator)

Diagrams (ImageGenerator)

Diagrams (WDC skin)

Diagrams (Belchertown skin)

Growing degree days

Display values (CheetahGenerator)

Diagrams (ImageGenerator)

Diagrams (WDC skin)

Diagrams (Belchertown skin)

Evapotranspiration

Display values (CheetahGenerator)

Diagrams (ImageGenerator)

Special derived meteorological readings

Display values (CheetahGenerator)

Diagrams (ImageGenerator)

Diagrams (Belchertown skin)

Radiation energy

Display values (CheetahGenerator)

Diagrams (ImageGenerator)

Diagrams (Belchertown skin)

NOAA-like Table

Soil moisture

Special time spans

Arbitrary offset to UTC

Local Mean Time of the station location

Daylight timespan

Algorithm:

Grünlandtemperatursumme (GTS)

Radiation energy

Daylight timespan

Barometer

Sources:

Links: