**-R**\ *west*/*east*/*south*/*north*\ [/*zmin*/*zmax*][**+r**][**+u**\ *unit*]

    Specify the region of interest. |Add_-Rgeo|

    The region may be specified in one of several ways:

    1. **-R**\ *west*/*east*/*south*/*north*. This is the standard way to specify geographic regions
       when using map projections where meridians and parallels are rectilinear. The coordinates may be specified in
       decimal degrees or in [±]dd:mm[:ss.xxx][**W**\|\ **E**\|\ **S**\|\ **N**] format.

    #. **-R**\ *west*/*south*/*east*/*north*\ **+r**. This form is useful for map projections that are oblique,
       making meridians and parallels poor choices for map boundaries. Here, we instead specify the lower left corner
       and upper right corner geographic coordinates, followed by the modifier **+r**. This form guarantees a
       rectangular map even though lines of equal longitude and latitude are not straight lines.

    #. **-R**\ **g** or **-R**\ **d**. These forms can be used to quickly specify the global domain (0/360 for **-Rg**
       and -180/+180 for **-Rd** in longitude, with -90/+90 in latitude).

    #. **-R**\ *code1,code2,...*\ [**+e**\ \|\ **r**\ \|\ **R**\ *incs*]. This indirectly supplies the region by
       consulting the DCW (Digital Chart of the World) database and derives the bounding regions for one or more
       countries given by the codes. Simply append one or more comma-separated countries using either the two-character
       `ISO 3166-1 alpha-2 convention <https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2>`_ (e.g., NO) or the full
       country name (e.g., Norway). To select a state within a country (if available), append .state (e.g, US.TX),
       or the full state name (e.g., Texas). To specify a whole continent, spell out the full continent name (e.g., -RAfrica).
       Finally, append any :ref:`DCW collection <dcw-collections>` abbreviations or full names for the extent of
       the collection or named region. All names are case-insensitive. The following modifiers can be appended:

        - **+r** to adjust the region boundaries to be multiples of the steps indicated by *inc*, *xinc*/*yinc*, or
          *winc*/*einc*/*sinc*/*ninc* [default is no adjustment]. For example, **-R**\ *FR*\ **+r**\ 1 will select the
          national bounding box of France rounded to nearest integer degree, where *inc* can be positive to expand the
          region or negative to shrink the region.
        - **+R** to adjust the region by adding the amounts specified by *inc*, *xinc*/*yinc*, or
          *winc*/*einc*/*sinc*/*ninc* [default is no extension], where *inc* can be positive to expand the
          region or negative to shrink the region.
        - **+e** to adjust the region boundaries to be multiples of the steps indicated by *inc*, *xinc*/*yinc*, or
          *winc*/*einc*/*sinc*/*ninc*, while ensuring that the bounding box is adjusted by at least 0.25 times the
          increment [default is no adjustment], where *inc* can be positive to expand the region or negative to shrink
          the region.

    #. **-R**\ *xmin*/*xmax*/*ymin*/*ymax*\ [**+u**\ *unit*] specifies a region in projected units (e.g., UTM meters)
       where *xmin*/*xmax*/*ymin*/*ymax* are Cartesian projected coordinates compatible with the chosen projection
       (**-J**) and *unit* is an allowable :ref:`distance unit <dist-units>` [e]; we inversely project to determine the
       actual rectangular geographic region. For projected regions centered on (0,0) you may use the short-hand
       **-R**\ *halfwidth*\ [/*halfheight*]\ **+u**\ *unit*, where *halfheight* defaults to *halfwidth* if not given.
       This short-hand requires the **+u** modifier.

    #. **-R**\ *justify*\ *lon0*/*lat0*/*nx*/*ny*, where *justify* is a 2-character combination of
       **L**\|\ **C**\|\ **R** (for left, center, or right) and **T**\|\ **M**\|\ **B** (for top, middle, or bottom)
       (e.g., **BL** for lower left). The two character code *justify* indicates which point on a rectangular region
       region the *lon0*/*lat0* coordinates refer to and the grid dimensions *nx* and *ny* are used with grid spacings
       given via **-I** to create the corresponding region. This method can be used when creating grids. For example,
       **-RCM**\ *25*/*25*/*50*/*50* specifies a *50*\ x\ *50* grid centered on *25*\ ,\ *25*.

    #. **-R**\ *gridfile*. This will copy the domain settings found for the grid in specified file. Note that depending
       on the nature of the calling module, this mechanism will also set grid spacing and possibly the grid registration
       (see :ref:`reference/options:Grid registration: The **-r** option`\ ).

    #. **-Ra**\ [**uto**] or **-Re**\ [**xact**]. Under modern mode, and for *plotting* modules only, you can automatically
       determine the region from the data used. You can either get the exact area using **-Re** [Default if no **-R**
       is given] or a slightly larger area sensibly rounded outwards to the next multiple of increments that depend on
       the data range using **-Ra**.
