NAME

       plmapline - Plot all or a subset of Shapefile data using lines in world coordinates

SYNOPSIS

       plmapline(mapform, name, minx, maxx, miny, maxy, plotentries, nplotentries)

DESCRIPTION

       Plot all or a subset of Shapefile data using lines in world coordinates. Our 19th standard
       example demonstrates how to use this function. This function plots data from  a  Shapefile
       using  lines  as  in  plmap(3plplot),  however it also has the option of also only drawing
       specified elements from the Shapefile. The vector of indices of the required elements  are
       passed  as  a  function  argument.  The  Shapefile  data  should  include  a metadata file
       (extension.dbf) listing all items within the Shapefile. This file can be  opened  by  most
       popular  spreadsheet  programs  and  can  be  used to decide which indices to pass to this
       function.

       Redacted form: plmapline(mapform, name, minx, maxx, miny, maxy, plotentries)

       This function is used in example 19.

ARGUMENTS

       mapform (PLMAPFORM_callback(3plplot), input)
              A user supplied function to transform the coordinates given in the shapefile into a
              plot  coordinate  system.  By using this transform, we can change from a longitude,
              latitude coordinate to a polar  stereographic  project,  for  example.   Initially,
              x[0]..[n-1]  are  the  longitudes and y[0]..y[n-1] are the corresponding latitudes.
              After the call to mapform(), x[] and y[] should be replaced  by  the  corresponding
              plot coordinates. If no transform is desired, mapform can be replaced by NULL.

       name (PLCHAR_VECTOR(3plplot), input)
              An  ascii  character  string  specifying  the file name of a set of Shapefile files
              without the file extension.

       minx (PLFLT(3plplot), input)
              The minimum x value to be plotted. This must be in the same units as  used  by  the
              Shapefile.  You  could use a very large negative number to plot everything, but you
              can improve performance by limiting the area drawn. The units must match  those  of
              the Shapefile projection, which may be for example longitude or distance. The value
              of minx must be less than the value of maxx.

       maxx (PLFLT(3plplot), input)
              The maximum x value to be plotted. You could  use  a  very  large  number  to  plot
              everything, but you can improve performance by limiting the area drawn.

       miny (PLFLT(3plplot), input)
              The  minimum  y  value to be plotted. This must be in the same units as used by the
              Shapefile. You could use a very large negative number to plot everything,  but  you
              can  improve  performance by limiting the area drawn. The units must match those of
              the Shapefile projection, which may be for example latitude or distance. The  value
              of miny must be less than the value of maxy.

       maxy (PLFLT(3plplot), input)
              The  maximum  y  value  to  be  plotted.  You could use a very large number to plot
              everything, but you can improve performance by limiting the area drawn.

       plotentries (PLINT_VECTOR(3plplot), input)
              A vector containing the zero-based indices of the Shapefile elements which will  be
              drawn. Setting plotentries to NULL will plot all elements of the Shapefile.

       nplotentries (PLINT(3plplot), input)
              The number of items in plotentries.  Ignored if plotentries is NULL.

AUTHORS

       Many  developers  (who  are credited at http://plplot.org/credits.php) have contributed to
       PLplot over its long history.

SEE ALSO

       PLplot documentation at http://plplot.org/documentation.php.

                                          February, 2023                       PLMAPLINE(3plplot)