Function:s2errb

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s2errb

Draw error bars at the coordinates (xpts[i], ypts[i], zpts[i]).

Prototype

void s2errb(int dir, int n, float *xpts, float *ypts, float *zpts, float *edelt, int termsize);

Description

Draw error bars at the coordinates (xpts[i], ypts[i], zpts[i]). Error bars are drawn in the direction indicated by argument dir as described below. One-sided error bar lengths are given by edelt, such that for error bars in eg. the x direction, error bars are drawn to xpts[i]+edelt[i], to xpts[i]-edelt[i], or to both. Argument termsize gives the size of the terminals to draw for each error bar; it is given in an integer increment of the current linewidth. Eg. if t=1, then end points are one pixel larger than the line width used to draw the bars.

dir: 1 for error bar in +x direction
2... +y...
3... +z...
4... -x...
5... -y...
6... -z...
7... +/-x...
8... +/-y...
9... +/-z...


PGPLOT Equivalent

PGERRB

Code Example

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "s2plot.h"


/* A modified version of sample progam s2uc1.c */

int main(int argc, char *argv[])
{
  int i;
  float np = 100;               /* point population size */
  float *xpts, *ypts, *zpts;    /* point positions */
  float *expts,*eypts,*ezpts;   /* error bar lengths */
  int symbol = 0;               /* -2 = infinitesimally small dot */
  float x1 = -100.0, x2 = +100.0;
  float y1 = -100.0, y2 = +100.0;
  float z1 = -100.0, z2 = +100.0;

  s2opend("/?",argc,argv);

  /* set world coordinate range */
  s2swin(x1,x2, y1,y2, z1,z2);

  /* generate a set of points extending over world coordinate space */
  xpts = (float *)calloc(np, sizeof(float));
  ypts = (float *)calloc(np, sizeof(float));
  zpts = (float *)calloc(np, sizeof(float));
  expts = (float*)calloc(np, sizeof(float));
  eypts = (float*)calloc(np, sizeof(float));
  ezpts = (float*)calloc(np, sizeof(float));


  for (i = 0; i < np; i++) {
    xpts[i] = x1 + (float)(rand()) / (float)RAND_MAX * (x2 - x1);
    ypts[i] = y1 + (float)(rand()) / (float)RAND_MAX * (y2 - y1);
    zpts[i] = z1 + (float)(rand()) / (float)RAND_MAX * (z2 - z1);
    expts[i]=(float)(rand()) / (float)RAND_MAX * (x2-x1)*0.05;
    eypts[i]=fabsf(ypts[i]) * 0.1;
    ezpts[i]= (z2-z1)*0.1;
  }

  /* plot red points */
  s2sci(S2_PG_RED);
  s2pt(np, xpts, ypts, zpts, symbol);

  /* plot various error bars */
  s2sci(S2_PG_WHITE);
  s2errb(4, np, xpts, ypts, zpts, expts, 1);
  s2sci(S2_PG_GREEN);
  s2errb(2, np, xpts, ypts, zpts, eypts, 2);
  s2sci(S2_PG_ORANGE);
  s2errb(9, np, xpts, ypts, zpts, ezpts, 3);

  /* draw and label a box around the points, in white */
  s2sci(S2_PG_WHITE);
  s2box("BCDET",0,0,"BCDET",0,0,"BCDET",0,0);

  s2show(1);

  return 0;



}

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