====== Quick plots with Ferret ======

[[https://ferret.pmel.noaa.gov/Ferret/|Ferret]] is an interactive computer visualization and analysis environment designed to meet the needs of oceanographers and meteorologists analyzing gridded data sets. It is very useful to create quick plots to check what is going on with the data. Below a few very basic examples are given to illustrate how to quickly visualize data with Ferret.\\ 

In order to use Ferret on levante, load it via 

<code bash>
module load ferret
</code>

Start Ferret by

<code ferret>
ferret
</code>

in the shell command prompt, the ferret command prompt will look like

<code ferret>
yes? 
</code>

Ferret expects gridded data, i.e. on a longitude-latitude-height-time grid. As an example, say you have a gridded (0.05°x0.05°; this is high resolution) file of surface temperature from the ICON dpp0016 simulation. You can load this file into ferret via:

<code ferret>
yes? use dpp0016_ts_005x005.nc
</code>

You can inspect the data via:

<code ferret>
yes? show data

currently SET data sets:
    1> ./dpp0016_ts_005x005.nc  (default)
 name     title                             I         J         K         L         M         N
 TS       surface temperature              1:7200     1:3600     ...       1:297     ...       ...
</code>

You can see the longitude (7200 data points), latitude (3600) and time (297 days).\\

To make a plot of the tropical Atlantic averaged over the entire time period, do (it may take some time because the file is large):

<code ferret>
yes? shade TS[x=60W:20E,y=30S:30N,t=@ave]
yes? go land
</code>
{{:analysis:postprocessing_icon:3.plottting:ferret:dpp0016_005x005_ts_ta.png?400|}}


To make a plot of a timeseries of surface temperature over a spatial mean of some region in the tropical Atlantic, do:
<code ferret>
yes? plot TS[x=30W:10E@ave,y=5S:5N@ave]
</code>
{{:analysis:postprocessing_icon:3.plottting:ferret:dpp0016_005x005_ts_ta_timeseries.png?400|}}

Exit ferret via
<code ferret>
yes? q
</code>