|No-spaces|

Description
-----------

**grdvector** reads two 2-D grid files which represents the *x*\ - and
*y*\ -components of a vector field and produces a vector field plot by
drawing vectors with orientation and length according to the information
in the files. Alternatively, polar coordinate *r*, *theta* grids may be given
instead.

Required Arguments
------------------

*compx.nc*
    Contains the x-components of the vector field.
*compy.nc*
    Contains the y-components of the vector field. (See GRID FILE FORMATS below.)

.. _-J:

.. |Add_-J| unicode:: 0x20 .. just an invisible code
.. include:: explain_-J.rst_

Optional Arguments
------------------

.. _-A:

**-A**
    The grid files contain polar (r, theta) components instead of
    Cartesian (x, y) [Default is Cartesian components].

.. _-B:

.. include:: explain_-B.rst_

.. _-C:

.. include:: use_cpt_grd.rst_

.. _-G:

**-G**\ *fill*
    Sets color or shade for vector interiors [Default is no fill].

.. _-I:

**-I**\ [**x**]\ *dx*\ [/*dy*]
    Only plot vectors at nodes every *x\_inc*, *y\_inc* apart (must be
    multiples of original grid spacing). Append **m** for arc minutes or
    **s** for arc seconds.  Alternatively, use **-Ix** to specify the
    multiples *multx*\ [/*multy*] directly [Default plots every node].

.. _-N:

**-N**
    Do NOT clip vectors at map boundaries [Default will clip].

.. _-Q:

**-Q**\ *parameters*
    Modify vector parameters. For vector heads, append vector head
    *size* [Default is 0, i.e., stick-plot]. See VECTOR ATTRIBUTES for
    specifying additional attributes.

.. _-R:

.. |Add_-R| replace:: Specify a subset of the grid.
.. include:: explain_-R.rst_

.. _-S:

**-S**\ [**i**\|\ **l**]\ *scale*
    Sets scale for vector plot lengths in data units per plot distance measurement unit. 
    Append **c**, **i**, or **p** to indicate the desired plot distance measurement
    unit (cm, inch, or point); if no unit is given we use the default value that
    is controlled by :term:`PROJ_LENGTH_UNIT`.  Vector lengths converted via plot unit
    scaling will plot as straight Cartesian vectors and their lengths are not
    affected by map projection and coordinate locations.
    For geographic data you may alternatively give *scale* in data units per map distance
    unit (see `Units`_). Then, your vector magnitudes (in data units) are scaled to map
    *distances* in the given distance unit, and finally projected onto the Earth to give
    *plot* dimensions.  These are geo-vectors that follow great circle paths and their
    lengths may be affected by the map projection and their coordinates.  Finally, use
    **-Si** if it is simpler to give the reciprocal scale in plot length or distance units
    per data unit.  To report the minimum, maximum, and mean data and plot vector lengths
    of all vectors plotted, use **-V**.  Alternatively, use **-Sl**\ *length* to set a fixed
    plot length for all vectors.

.. _-T:

**-T**
    Means the azimuths of Cartesian data sets should be adjusted according to the
    signs of the scales in the x- and y-directions [Leave alone].  This option can
    be used to convert vector azimuths in cases when a negative scale is used in
    one of both directions (e.g., positive down).

.. _-U:

.. include:: explain_-U.rst_

.. _-V:

.. |Add_-V| unicode:: 0x20 .. just an invisible code
.. include:: explain_-V.rst_

.. _-W:

**-W**\ *pen*
    Set pen attributes used for vector outlines [Default: width =
    default, color = black, style = solid].

.. _-X:

.. include:: explain_-XY.rst_

.. _-Z:

**-Z**
    The theta grid provided contains azimuths rather than directions (implies **-A**).

.. |Add_-f| unicode:: 0x20 .. just an invisible code
.. include:: explain_-f.rst_

.. |Add_perspective| unicode:: 0x20 .. just an invisible code
.. include:: explain_perspective.rst_

.. include:: explain_-t.rst_

.. include:: explain_help.rst_

.. include:: explain_distunits.rst_

.. include:: explain_grd_inout_short.rst_

.. include:: explain_vectors.rst_
