jsGraph

Error bars

Scientific data often comes along with error bars. You can chose to display bars or boxes using the serie.setErrorStyle(); method.

Defining errors

Errors are essentially stored in multi-level array, such as : [ [ [ [ 0.5, 0.2 ], [ 0.8, 0.2 ] ] ] ]

The first level corresponds to your data. Error at index n will be assigned to dat at index n

The second level differentiates error bars in the x or the y direction. First argument is y, second is x

The third level reprensents bars or boxes. To know which one is which, refer to the order you specified in serie.setErrorStyle function. Use false or null not to display errors of this level for this particular point

The fourth level represents above/below or lefthand/righthand error bars/boxes. Use only one argument to make it symmetric.

Source code

var seriedata = [],
  error = [];

for ( var i = 0; i < 5; i += 0.5 ) {
  seriedata.push( [ i, Math.sin( i ) ] );
  error.push( [
    [
      [ Math.random() / 10, Math.random() / 10 ],
      [ ( 1 + Math.random() ) / 5, ( 1 + Math.random() ) / 5 ]
    ]
  ] );
}

var graphinstance = new Graph( domGraph );

graphinstance.newSerie( "serieTest", {}, "scatter", function( serie ) {

  serie
    .setLabel( "My serie" )
    .autoAxis()
    .setData( seriedata )
    .setDataError( error )
    .setErrorStyle( [ 'box', 'bar' ] );

  graphinstance.redraw();
  graphinstance.drawSeries();
} );