Syntax:
splot '<file_name>' {binary <binary list>} {{nonuniform} matrix} {index <index list>} {every <every list>} {using <using list>}
The special filenames "" and "-" are permitted, as in plot. See special-filenames (p. ).
In brief, binary and matrix indicate that the data are in a special form, index selects which data sets in a multi-data-set file are to be plotted, every specifies which datalines (subsets) within a single data set are to be plotted, and using determines how the columns within a single record are to be interpreted.
The options index and every behave the same way as with plot; using does so also, except that the using list must provide three entries instead of two.
The plot option smooth is not available for splot, but cntrparam and dgrid3d provide limited smoothing capabilities.
Data file organization is essentially the same as for plot, except that each point is an (x,y,z) triple. If only a single value is provided, it will be used for z, the block number will be used for y, and the index of the data point in the block will be used for x. If two or four values are provided, gnuplot uses the last value for calculating the color in pm3d plots. Three values are interpreted as an (x,y,z) triple. Additional values are generally used as errors, which can be used by fit.
Single blank records separate blocks of data in a splot datafile; splot treats blocks as the equivalent of function y-isolines. No line will join points separated by a blank record. If all blocks contain the same number of points, gnuplot will draw cross-isolines between points in the blocks, connecting corresponding points. This is termed "grid data", and is required for drawing a surface, for contouring (set contour) and hidden-line removal (set hidden3d). See also splot grid_data (p. ).
It is no longer necessary to specify parametric mode for three-column
splots.