Friday, April 5, 2013

Vertical line markers in R using geom_vline

Say you have a two data sets that share a common dimension/axis only.  Here's an example:

# Event csv
2013-04-03 22:59:05.061Z,A
2013-04-03 22:59:05.061Z,B
2013-04-03 22:59:07.109Z,C
2013-04-03 22:59:07.115Z,D
2013-04-03 22:59:07.209Z,E

# Performance data
box1;1;2013-04-03 22:59:02 UTC;-1;10.53;0.00;2.01;0.50;0.00;86.97
box1;1;2013-04-03 22:59:03 UTC;-1;0.25;0.00;0.00;0.00;0.00;99.75
box1;1;2013-04-03 22:59:04 UTC;-1;0.00;0.00;0.25;0.25;0.00;99.50
box1;1;2013-04-03 22:59:05 UTC;-1;10.72;0.00;1.00;0.25;0.00;88.03
box1;1;2013-04-03 22:59:06 UTC;-1;10.67;0.00;10.67;0.00;0.25;78.41
box1;1;2013-04-03 22:59:07 UTC;-1;5.01;0.00;9.02;3.51;0.00;82.46
box1;1;2013-04-03 22:59:08 UTC;-1;12.28;0.00;11.53;4.26;0.25;71.68
box1;1;2013-04-03 22:59:09 UTC;-1;15.88;0.00;11.66;10.92;0.50;61.04
You'd like to plot these values on one graph; one overlaid over the other. Based on the data from the example above, you'd like to plot the CPU user against the timestamp metric, then you'd like to add in markers to show events over the chart.

Here's a gist:

 Obviously, we need a better legend, y axis label and a title for this graph.. That's left as an exercise.

Tuesday, April 2, 2013

R and GFS.

Playing with NOAA's GFS data with R.


Here are some sample images.


  • Fetched data from NOAA (in particular this dataset).
  • Installed wgrib2.
  • Extracted the fields I was interested in from the grib2 file into netcdf
./grib2/wgrib2/wgrib2  -s  gfs.t12z.sfluxgrbf03.grib2  | grep :LAND | ./grib2/wgrib2/wgrib2 -i gfs.t12z.sfluxgrbf03.grib2 -netcdf land.netcdf
./grib2/wgrib2/wgrib2  -s  gfs.t12z.sfluxgrbf03.grib2  | grep TMP:2 | ./grib2/wgrib2/wgrib2 -i gfs.t12z.sfluxgrbf03.grib2 -netcdf temp2.netcdf
./grib2/wgrib2/wgrib2  -s  gfs.t12z.sfluxgrbf03.grib2  | grep VEG: | ./grib2/wgrib2/wgrib2 -i gfs.t12z.sfluxgrbf03.grib2 -netcdf vegetation.netcdf
./grib2/wgrib2/wgrib2  -s  gfs.t12z.sfluxgrbf03.grib2  | grep TCDC: | ./grib2/wgrib2/wgrib2 -i gfs.t12z.sfluxgrbf03.grib2 -netcdf cloud.netcdf

  • You can also view the available fields using:
./grib2/wgrib2/wgrib2  -s  gfs.t12z.sfluxgrbf03.grib2  | less

Having fun

Started R and installed netcdf and fields:
Then used the following gist in R.