    **+a**\ *angle*
       Place annotations at a fixed angle, or use **+an** for contour-normal and
       **+ap** for contour-parallel [Default].  For **+ap**, you may optionally
       append **u** for up-hill and **d** for down-hill cartographic annotations.

    **+c**\ *dx*\ [/*dy*]
       Sets the clearance between label and optional text box. Append
       **c**\|\ **i**\|\ **p** to specify the unit or % to indicate a
       percentage of the label font size [15%].

    **+d**
       Turns on debug mode, which will draw helper points and lines to illustrate
       the workings of the contour line setup.

    **+e**
       Delay the plotting of the text. This is used to build a clip path
       based on the text, then lay down other overlays while that clip path
       is in effect, then turning off clipping with :doc:`clip` **-C** which
       finally plots the original text. Note that the clip path may 
       truncate other regions where there is no text overlap. Double check 
       to ensure the correct result is obtained as expected. Carefully selecting 
       the right place to run :doc:`clip` manually after each use of **+e** is recommended.

    **+f**\ *font*
       Sets the desired font [Default :term:`FONT_ANNOT_PRIMARY` with its
       size changed to 9p].

    **+g**\ [*color*]
       Selects opaque text boxes [Default is transparent]; optionally
       specify the color [Default is :term:`PS_PAGE_COLOR`].

    **+i**
       Invisible lines (i.e., hide the lines) [Default draws the lines]. This may be useful if all you want
       is to see annotations and labels and not the lines that guides them.

    **+j**\ *just*
       Sets label justification relative to the line center point [Default is **MC**].

    **+n**\ *dx*\ [/*dy*]
        Nudges the placement of labels by the specified amount (append
        **c**\|\ **i**\|\ **p** to specify the units). Increments
        are considered in the coordinate system defined by the
        orientation of the contour (contour is *x*, normal to contour is *y*);
        use **+N** to force increments in the overall
        plot x/y coordinates system [no nudging]. Not allowed with **+v**.

    **+o**
        Selects rounded rectangular text box [Default is rectangular].
        Not applicable for curved text (**+v**) and only makes sense for
        opaque text boxes.

    **+p**\ [*pen*]
        Draws the outline of text boxes [Default is no outline];
        optionally specify pen for outline [Default selects width = 0.25p,
        color = black, style = solid].

    **+r**\ *min\_rad*
        Will not place labels where the contours's radius of curvature is
        less than *min\_rad* [Default is 0].

    **+t**\ [*file*]
        Saves contour label x, y, angle, and text to *file* [Contour\_labels.txt].

    **+u**\ *unit*
        Appends *unit* to all contour labels. [Default is no unit].
        If **z** is appended we use the z-unit from the grid file.

    **+v**
        Specifies curved labels following the contour [Default is straight
        labels].

    **+w**\ *n*
        Specifies how many (*x*,\ *y*) points will be used to estimate
        label angles [automatic].

    **+x**\ [*first,last*]
	Adds *first* and *last* to these two labels [,'] placed at either end of a quoted line.
	This modifier is only allowed when **-SqN**\ 2 is used to place a label at the
	start and stop of a line (the default adds a prime to the end label).

    **+=**\ *prefix*
        Prepends *prefix* to all contour labels. [Default is no prefix].
