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.

                                                  October, 2024                               PLMAPLINE(3plplot)