writeDataset: Create and save to disk a single variable dataset
Description
The daily and hourly files conatin many data elements
Typically one works with a single variable at time. This function
allows you to create subsets of data that have one and only one variable
in the file. The monolithic file, of course, can be read with
read.table. This function uses read.table, but skips the columns
not requested and writes out the subset of data
Filename of the monolithic file. for example:
CRN_Hourly_2011-09-19.dat or CRN_Daily_2011-09-19.dat.
The function collateDaily for example will create
a file of all stations and all variables and append a date stamp.
this function reads that data and selects a single variable from the
35+ variables in the datasets
cnames
The column names either colnamesDaily or colnamesHourly
It must match the file you are reading: hourly for hourly; daily for daily
varname
the variable you want to extract. It must be quoted
exactly as it appears in the colnames constant
Value
requested.
Details
The function masks off all unnecessaru columns and writes
a dataset. The station ID ( WBANNO) and date and time are also saved.
one variable and one variable only is added to these base variables
and output to the file