No, i just adjustet the vaporpressure.py example.
But i see what you mean, i have to calculate it by my own, this means i
have to load all data for a day and calculate it.
im not shure i can do this.
i quess its easyer and better to do this in the database.
gjr80 schrieb am Donnerstag, 17. Dezember 2020 um 20:37:57 UTC+1:
> Hi,
>
> When you wrote your xtype extension what methods did you implement? Did
> you implement get_aggregate()?
>
> Gary
>
> On Friday, 18 December 2020 at 02:41:34 UTC+10 bwal...@gmail.com wrote:
>
>> Hi
>> i made a xtype extension for a wetbulp temperaur. this worsks fine with
>> the $current tag and the image generator.
>>
>> with tag $day.wetbulp_t.min the chetagenerator rise no error but whrites
>> $day.wetbulp_t.min in the file...
>>
>> do i have do add wetbulp_t in database for get this to work?
>>
>
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#
# Copyright (c) 2020 Tom Keffer <tkef...@gmail.com>
#
# See the file LICENSE.txt for your full rights.
#
"""This example shows how to extend the XTypes system with a new type, wetbulp_t, the vapor
pressure of water.
REQUIRES WeeWX V4.2 OR LATER!
To use:
1. Stop weewxd
2. Put this file in your user subdirectory.
3. In weewx.conf, subsection [Engine][[Services]], add WetbulptemperureService to the list
"xtype_services". For example, this means changing this
[Engine]
[[Services]]
xtype_services = weewx.wxxtypes.StdWXXTypes, weewx.wxxtypes.StdPressureCooker, weewx.wxxtypes.StdRainRater
to this:
[Engine]
[[Services]]
xtype_services = weewx.wxxtypes.StdWXXTypes, weewx.wxxtypes.StdPressureCooker, weewx.wxxtypes.StdRainRater, user.wetbulp.wetbulpService
4. Restart weewxd
"""
import math
import weewx
import weewx.units
import weewx.xtypes
from weewx.engine import StdService
from weewx.units import ValueTuple
class WetBulp(weewx.xtypes.XType):
def __init__(self, algorithm='simple'):
# Save the algorithm to be used.
self.algorithm = algorithm.lower()
def get_scalar(self, obs_type, record, db_manager):
# We only know how to calculate 'vapor_p'. For everything else, raise an exception UnknownType
if obs_type != 'wetbulp_t':
raise weewx.UnknownType(obs_type)
# We need outTemp in order to do the calculation.
if 'outTemp' not in record or record['outTemp'] is None:
raise weewx.CannotCalculate(obs_type)
# We have everything we need. Start by forming a ValueTuple for the outside temperature.
# To do this, figure out what unit and group the record is in ...
unit_and_group = weewx.units.getStandardUnitType(record['usUnits'], 'outTemp')
# ... then form the ValueTuple.
outTemp_vt = ValueTuple(record['outTemp'], *unit_and_group)
# Both algorithms need temperature in Celsius, so let's make sure our incoming temperature
# is in that unit. Use function convert(). The results will be in the form of a ValueTuple
outTemp_C_vt = weewx.units.convert(outTemp_vt, 'degree_C')
# Get the first element of the ValueTuple. This will be in Celsius:
outTemp_C = outTemp_C_vt[0]
# We need outHumidity in order to do the calculation.
if 'outHumidity' not in record or record['outHumidity'] is None:
raise weewx.CannotCalculate(obs_type)
# We have everything we need. Start by forming a ValueTuple for the outside humidity.
# To do this, figure out what unit and group the record is in ...
unit_and_group = weewx.units.getStandardUnitType(record['usUnits'], 'outHumidity')
# ... then form the ValueTuple.
outHumidity_vt = ValueTuple(record['outHumidity'], *unit_and_group)
# Algorithms need humidity in percent, so let's make sure our incoming humidity
# is in that unit. Use function convert(). The results will be in the form of a ValueTuple
#outHumidity_P_vt = weewx.units.convert(outTemp_vt, 'group_percent')
# Get the first element of the ValueTuple. This will be in Percent:
outHumidity_P = outHumidity_vt[0]
# Now we can use the formula. Results will be in degree celcius. Create a ValueTuple out of it:
w_b = ValueTuple(-5.809 + 0.058 * outHumidity_P + 0.697 * outTemp_C + 0.003 * outHumidity_P * outTemp_C, 'degree_C', 'group_temperature')
# We have the wetbulp temeratur as a ValueTuple. Convert it back to the units used by
# the incoming record and return it
return weewx.units.convertStd(w_b, record['usUnits'])
class wetbulpService(StdService):
""" WeeWX service whose job is to register the XTypes extension wetbulp with the
XType system.
"""
def __init__(self, engine, config_dict):
super(wetbulpService, self).__init__(engine, config_dict)
# Get the desired algorithm. Default to "simple".
try:
algorithm = config_dict['WetBulp']['algorithm']
except KeyError:
algorithm = 'simple'
# Instantiate an instance of VaporPressure:
self.vp = WetBulp(algorithm)
# Register it:
weewx.xtypes.xtypes.append(self.vp)
def shutDown(self):
# Remove the registered instance:
weewx.xtypes.xtypes.remove(self.vp)
# Tell the unit system what group our new observation type, 'vapor_p', belongs to:
weewx.units.obs_group_dict['wetbulp_t'] = "group_temperature"
