This option selects the region to plot. Note that for most operations the whole field is computed, so that one can choose other regions afterwards. Only for EOFs, SVDs, EOTs and verification measures the data is actually restricted to the region indicated.

The default is the area of the field. When the field is global, the default longitude range is from 180°W to 180°E (Europe/Africa-biased).

If a field is unexpectedly empty, try adding or subtracting 360° to the longitude. I try to map everything to a common range, but this sometimes fails.

Degrees south and west should be indicated by negative numbers. Note that ranges should always be from negative to positive, so from south to north and west to east. A range -10°N to -20°N will often not work as it goes from north to south. A range -10°W to -20°W will give a plot almost circling the earth, which is probably not what you want.

A small region will select a high-resolution background map. for a large region a low-resolution version is used.

When the maps are computed for a range of time values (seasons or lags) there is the possibility to draw the results as a time-lon or time-lat plot. The other spatial dimension then indicates a range over which the values are averaged
This feature currently does not work corectly, contact me if you need it now.