knmi

knmi

Ruby API to access Royal Netherlands Meteorological Institute daily climate data Access climatological data as provided by the Royal Netherlands Meteorological Institute through the http get forms for daily and hourly data

• http://www.knmi.nl/climatology/daily_data/getdata_day.cgi
• http://www.knmi.nl/klimatologie/uurgegevens/getdata_uur.cgi

This gem was constructed using information from the KNMI climate data pages here.

• Hourly data (Dutch) - http://www.knmi.nl/klimatologie/uurgegevens/scriptxs-nl.html#uur
• Daily data (English) - http://www.knmi.nl/climatology/daily_data/scriptxs-en.html
• Select Data with a form, listed below are links to metadata about each station http://www.knmi.nl/climatology/daily_data/selection.cgi

Installation

gem install httparty
gem install geokit

gem install knmi

Example Usage

Launch console e.g. irb at the command line

Quick Script

require 'knmi'

station = KNMI.station_by_id(235)
parameters = KNMI.parameters(period = "daily", params = nil, categories = ["TEMP", "WIND"])
starts = Time.utc(2010, 6, 28) # 2010 April 28th
ends = Time.utc(2010, 6, 29) # 2010 April 29th
request = KNMI.get_data(station, parameters, starts, ends)
data = KNMI.convert(parameters, request)

Elaborated Script

require 'knmi'

# Get station object by station ID
station = KNMI.station_by_id(235)

station
#=> #<KNMI::Station:0x0000010133c938> # A struct object

# Available Instance Variables
station.instance_variables
#=> [:@id, :@name, :@elevation, :@photo, :@map, :@web, :@instrumentation, :@coordinates]
station.id
#=> 235
station.name
#=>"De kooy"
station.coordinates
#=> 52.924,4.785


# Get parameter object at the time interval you wish to use "hourly" or "daily"
# Params can be a single term or an array of terms such as "TG" or ["TG", TX]
# Categories can be a single term or an array of terms such as "WIND" or ["WIND", "TEMP"]
parameters = KNMI.parameters(period = "daily", params = nil, categories = ["TEMP", "WIND"])

parameters # returns an array of parameter objects
#=> [#<KNMI::Parameters:0x000001011387e0 @parameter="TX", @category="TEMP", @description="Maximum Temperature", @validate="n.integer?", @conversion="n / 10", @units="C", @period="daily">]

# Available Instance Variables
parameters[0].instance_variables
#=>[:@parameter, :@category, :@description, :@validate, :@conversion, :@units, :@period]

parameters[0].parameter
#=> "TX"


# Define Time period of interest
starts = Time.utc(2010, 6, 28) 	# 2010 April 28th
ends = Time.utc(2010, 7, 01) 		# 2010 April 29th

# Get Data using previously retrieved objects
request = KNMI.get_data(station, parameters, starts, ends)

# Available Instance Variables
request.instance_variables
#=> [:@query, :@data]

request.query
#=>["stns=235", "vars=TX", "start=20100628", "end=20100629"]

request.data
#=>[{:STN=>"235", :YYYYMMDD=>"20100628", :TX=>"263"}, {:STN=>"235", :YYYYMMDD=>"20100629", :TX=>"225"}]

request.data[0]
#=>{:STN=>"235", :YYYYMMDD=>"20100628", :TX=>"263"}


# Convert data from storage format to operating format
data = KNMI.convert(parameters, request)

Available Parameters

All available recorded parameters can be found in the file .data/data_key.yml This file contains the parameter name, category, description, a script to validate the data, a script to convert the data to to appropriate units, units, and the appropriate period.

Daily Data

Parameter	Category	Description
YYYYMMDD		Time Stamp
DDVEC	WIND	Wind Direction
FHVEC	WIND	Vector Mean Wind Speed
FG	WIND	Daily Mean Wind Speed
FHX	WIND	Maximum Hourly Mean Windspeed
FHXH	WIND	Hourly Division at Which Maximum Wind Speed Was Measured
FHN	WIND	Minimum Hourly Mean Windspeed
FHNH	WIND	Hourly Division at Which Minimum Wind Speed Was Measured
FXX	WIND	Maximum Instantaneous Wind Speed
FXXH	WIND	Hourly Division at Which Maximum Instantaneous Wind Speed Was Measured
TG	TEMP	Daily Mean Temperature
TN	TEMP	Minimum Temperature
TNH	TEMP	Hourly Division in Which Minimum Temperature Was Measured
TX	TEMP	Maximum Temperature
TXH	TEMP	Hourly Division in Which Maximum Temperature Was Measured
T10N	TEMP	Minimum Temperature at 10 Cm Above Surface
T10NH	TEMP	Six Hourly Division at Which Minimum Temperature at 10 Cm Above Surface Was Measured
SQ	RADT	Sunshine Duration
SP	RADT	Percent of Maximum Sunshine Duration
Q	RADT	Global Radiation
DR	PRCP	Precipitation Duration
RH	PRCP	Daily Precipitation
RHX	PRCP	Maximum Hourly Precipitation
RHXH	PRCP	Hourly Division in Which Maximum Hourly Precipitation Was Measured
EV24	ATMS	Potential Evapotranspiration
PG	ATMS	Daily Mean Sea Level Pressure
PX	ATMS	Maximum Hourly Sea Level Pressure
PXH	ATMS	Hourly Division on Which Maximum Hourly Sea Level Pressure Was Measured
PN	ATMS	Minimum Hourly Sea Level Pressure
PNH	ATMS	Hourly Division in Which Minimum Hourly Sea Level Pressure Was Measured
VVN	VISB	Minimum Visibility
VVNH	VISB	Hourly Division in Which Minimum Visibility Was Measured
VVX	VISB	Maximum Visibility
VVXH	VISB	Hourly Division in Which Maximum Visibility Was Measured
NG	VISB	Mean Daily Cloud Cover
UG	ATMS	Daily Mean Relative Humidity
UX	ATMS	Maximum Relative Humidity
UXH	ATMS	Hourly Division in Which Maximum Relative Humidity Was Measured
UN	ATMS	Minimum Relative Humidity
UNH	ATMS	Hourly Division in Which Minimum Relative Humidity Was Measured

Hourly Data

Parameter	Category	Description
YYYYMMDD		Time Stamp
HH		Hour
DD	WIND	Mean wind direction during the 10-minute period preceding the time of observation
FH	WIND	Hourly mean wind speed
FF	WIND	Mean wind speed
FX	WIND	Maximum wind gust
T	TEMP	Air Temperature at 1.5 m
T10N	TEMP	Minimum Air Temperature at 10 cm in the preceding 6 hours
TD	TEMP	Dew Point Temperature
SQ	RDTN	Sunshine Duration
Q	RDTN	Golbal Radiation
DR	PRCP	Precipitation Duration
RH	PRCP	Precipitation
P	ATMS	Air Pressure
VV	VISB	Visibility
N	VISB	Cloud Cover
U	ATMS	Relative Humidity
M	WTHR	Fog
R	WTHR	Rainfall
S	WTHR	Snow
O	WTHR	Thunder
Y	WTHR	Ice
WW	WTHR	Weather Code

TODO

Write unit tests for lib/calculations/calculations.rb

Please Note the license included in the header source header

# DEZE GEGEVENS MOGEN VRIJ WORDEN GEBRUIKT MITS DE VOLGENDE BRONVERMELDING WORDT GEGEVEN:
# KONINKLIJK NEDERLANDS METEOROLOGISCH INSTITUUT (KNMI)
#
# THESE DATA CAN BE USED FREELY PROVIDED THAT THE FOLLOWING SOURCE IS ACKNOWLEDGED:
# ROYAL NETHERLANDS METEOROLOGICAL INSTITUTE

Copyright

Copyright (c) 2011 Patrick Galvin Schmitz [e-mail]. See LICENSE.txt for further details.