scrapeMeteo: Scrape meteorological data from <URL: meteo.enel.it>

In mbask/meteopv: Tools to scrape meteorological data and to estimate pv cells power generation

Description

enel.it does not provide any API. Meteorological parameters, including temperature and irradiance, are scraped from its website. Therefore even slight changes to HTML code may break the code. A forged POST request is sent to dettaglio_ajax.php. The request includes a fake cookie, the code for the town and the date for the forecast to be looked up. The website provides 8 forecasts of 12 variables a day:

1. "Te" (Air temperature) [^\circ C]

2. "Mc" (Current weather conditions), one of

   • "Sun"

   • "Burning sun"

   • "Scattered clouds"

   • "Broken clouds"

   • "Broken clouds and rain"

   • "Broken clouds, rain and snow"

   • "Broken clouds and light snow"

   • "Overcast clouds"

   • "Overcast clouds and rain"

   • "Overcast clouds and rain"

   • "Overcast clouds and snow"

   • "Overcast clouds, snow and rain"

   • "Overcast clouds, thunderstorms"

   • "Overcast clouds and mist"

   • "Fog"

   • "Broken clouds, rain, chance of thunderstorms"

   • "Overcast clouds and heavy rain"

   • "Overcast clouds and heavy snow"

3. "R" (Precipitation), one of

   • "No rain"

   • "Drizzle"

   • "Light rain"

   • "Moderate rain"

   • "Heavy rain"

   • "Very heavy rain"

   according to these classes of precipitation (mmH_2O):

   • <0.1

   • <2

   • <6

   • <10

   • <15

   • ≥q 15

4. "Wd" (Wind direction), classes of 11.25^\circ each. One of

   • "N"

   • "NNE"

   • "NE"

   • "ENE"

   • "E"

   • "ESE"

   • "SE"

   • "SSE"

   • "S"

   • "SSW"

   • "SW"

   • "WSW"

   • "W"

   • "WNW"

   • "NW"

   • "NNW"

5. "Ws" (Wind speed) [m/s]

6. "Tw" (Wind-corrected air temperature (ie Windchill)) [^\circ C]

7. "H" (Heat) [^\circ C]

8. "Rh" (Relative humidity) [\%]

9. "V" (Visibility) [m]

10. "P" (Air pressure) [hPa]

11. "Pt" (Pressure trend), one of

    • "-2"

    • "-1"

    • "0"

    • "1"

    • "2"

12. "G" (Irradiance) [W/m^2]

Usage

scrapeMeteo(location, dates = list(Sys.Date()),
  webAddress = "http://meteo.enel.it", timeOfDayNum = 8,
  variableLabels = c(Te = "Te", Mc = "Mc", R = "R", Wd = "Wd", Ws = "Ws", Tw =
  "Tw", H = "H", Rh = "Rh", V = "V", P = "P", Pt = "Pt", G = "G"))

Arguments

location	integer code linked to a geographical location in Enel DB. Check meteo.enel.it to get the code for your town or city
dates	a list of forecast dates, defaults to a list of 1 element (today date).
webAddress	the http address where meteorological data is to be scraped from. Defaults to http://meteo.enel.it
timeOfDayNum	how many times a day forecasts are provided. Defaults to 8, i.e. every 3 hours.
variableLabels	a named vector of 12 variable names, defaults to the labels provided in Description section

Value

a data.frame of 3 columns: time, variable, value

Note

Photovoltaic panel efficiency and temperature estimation needs air temperature and irradiance variables.

Author(s)

Marco Bascietto [e-mail]

Examples

## Not run: 
# Scrapes today and tomorrow meteorological data for 4 italian towns
places = c(Roma = 170094, Nepi = 170158, Bolzano = 172858, Siracusa = 172506)
scrapeDate <- Sys.Date()
lapply(places, function(place) {measures <- scrapeMeteo(place, dates = list(scrapeDate, scrapeDate + lubridate::days(1)))})

## End(Not run)

mbask/meteopv documentation built on May 21, 2019, 2:25 p.m.