Get daily or monthly data from a database and build input files *.dat and *.est
This function facilitates the creation of the input files needed by this package by retrieving the data from a database through an RODBC connection.
db2dat(varcli, anyi, anyf, minny=5, daily=TRUE, ch, dformat='%Y-%m-%d', vtable, vcode, vdate, vval, stable, scode, sname, sx, sy, sz)
varcli |
Acronym of the name of the studied climatic variable, as it will appear in all data file names. |
anyi |
Initial year of the data to be included in the file. |
anyf |
Final year of the data to be included in the file. |
minny |
Minimum number of years with data for a series to be included in the file. |
daily |
Logical flag indicating whether the data are daily (the default) or monthly (set |
ch |
Already open ODBC connection to the climatic database. |
dformat |
Date format in the database. |
vtable |
Name of the table containing our climatic variable. |
vcode |
Name of the variable containing station codes in the |
vdate |
Name of the variable containing dates in the |
vval |
Name of the climatic variable in the |
stable |
Name of the table containing station information (metadata). |
scode |
Name of the variable containing station codes in the table |
sname |
Name of the variable containing station names in the |
sx |
Name of the variable containing longitudes (degrees with decimals!) in the |
sy |
Name of the variable containing latitudes (degrees with decimals!) in the |
sz |
Name of the variable containing elevations (meters) in the |
This function creates the two input files needed by the homogenization functions of this package, ‘VAR_YEAR-YEAR.dat’ (holding the data) and ‘VAR_YEAR-YEAR.est’ (holding station coordinates, codes and names).
The table in the accessed database must contain either daily or monthly data (set daily=FALSE in this case). Otherwise the number of data per series will not be match the expected value and the function will fail.
Moreover, every data item must be in a different record in the database, as in this example table of monthly data (different variables for the same time step are O.K.):
Station Date T.max T.min Rel.Hum Precip Wind.speedS032 1991-01-01 12.1 -2.1 59 128.2 5.4S032 1991-02-01 13.2 -2.5 62 78.4 6.2...
But if the table in the database arranges all monthly values of one year (or all daily values of one month) in a single record, then this function will not retreive the data correctly.
This function does not return any value.
## Not run:
# First we must access our climatic database through RODBC, wich requires to
# have this package installed. System programs that allow ODBC connections to
# databases must also be installed and properly configured.
#
# For this example we will assume that our database is named "climate" and we
# access it with user "USER" and password "PASS". Then we open the connection
# with:
#
library(RODBC)
ch <- odbcConnect("climate",uid="USER",pwd="PASS")
#
# Now we want to use this function to gather all monthly relative humidity
# averages for the period 1961-2015, requiring a minimum of 10 years of data
# (not necessarily consecutive). We must use the corresponding names of tables
# and headers existing the the database, and putting the parameters in the
# required order we avoid the need to name them:
#
db2dat('HRel',1961,2015,10,FALSE,ch,'
'Station','Date','Value','stations','Station','Name','Longitude',
'Latitude','Elevation')
#
odbcClose(ch) #close the connection if you do not need it anymore
#
# Our data would now be ready to be homogenized with the homogen function:
#
homogen('HRel',1961,2015,vmin=0,vmax=100)
#
## End(Not run)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.