pyWeatherLink/conversions.py at master · OpenHackFarm/pyWeatherLink · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
"""

    This file is part of the pyWeatherLink package,
    Copyright 2008 by Henrik Persson <root@fulhack.info>.

    pyWeatherLink is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 2 of the License, or
    (at your option) any later version.

    pyWeatherLink is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with pyWeatherLink.  If not, see <http://www.gnu.org/licenses/>.

"""

import math

def f2c(f):
    c = (f-32) * (5.0/9.0)
    return round(c, 1)

def mph2kts(mph):
    kts = mph * 0.868976242
    return int(round(kts, 0))

def mph2ms(mph):
    ms = mph * 0.44704
    return round(ms, 1)

def inHg2hPa(inHg):
    return round(inHg * 33.8638816, 1)

# constants
a = 17.271
b = 237.7 # degC

def gamma(T,RH):
    g = (a * T / (b + T)) + math.log(RH/100.0)
    return g

def dewpoint_approximation(T, RH):
    gm = gamma(T,RH)
    Td = (b * gm) / (a - gm)

    return round(Td, 1)