Re: newbie- can I make a bar graph?

Thanks so much! Yes, it does work and it helped me a lot. Thanks again.
:)

-Jen

Ugo Taddei wrote:
> 
> Hi Stewart and hi all,
> 
> I've got some code to draw a 2D display with "bars". I've used
> VisADLineArray rather than VisADQuadArray, because I've got a display
> showing some 365 bars, which are packed up together so closely that one
> don't want them thick. (Thickness is nevertheless controlled with
> constant maps; see code below).
> 
> The idea here is to plot daily precipitation values as "bars" (i.e.
> thick lines).
> 
> So here we go:
> 
> day =   new RealType( "day", null, null );
> precip  =  new RealType( "Precipitation", null, null );
> 
> // the function precip = f( days )
> FunctionType func_Prec = new FunctionType( day , precip );
> 
> // here the day values, as a set, we'll have 365 values
> daySet = (Set) new Linear1DSet(  day  , (float) firstDay, (float)
> lastDay, 365);
> 
> // the flat field
> ff_Prec = new FlatField( func_Prec, daySet );
> 
> // the line array
>  pBars = new VisADLineArray();
> 
> // scalar maps
> xMap    = new  ScalarMap( day, Display.XAxis );
> yMap    = new  ScalarMap( precip, Display.YAxis);
> 
> 
> // more scalar maps: 1st for shaps, and 2nd for shape scale, i.e,
> responsible for sacling the shape according to RealType precip
> 
> pBarMap = new ScalarMap(precip, Display.Shape);
> pBarScaleMap = new ScalarMap(precip, Display.ShapeScale);
> 
> // create a dispay...
> display1 = new DisplayImplJ2D("display1");
> 
> // initalize pBars: 2 vertex (with (x,y,z), where z is ignored)
> pBars.vertexCount=2;
> // and coordinates: draw some "arbitrary" line; it's be scaled according
> to values of RealType precip
> 
> pBars.coordinates = new float[] {0.0f,  0.0f, 0.0f,    0.0f, -0.10f,
> 0.0f};
> 
> // let samples_precip be you precipitatios values:
> 
> float[][] samples_Precip = new float[ 1 ][ 365 ];
> 
> // fill array with values...
> // code to fill array...
> 
> // set samples:
> 
> ff_Prec.setSamples(samples_Precip);
> 
> // adda maps to display:
> 
> display1.addMap( xMap );
> display1.addMap( yMap1);
> display1.addMap(pBarMap);
> display1.addMap(pBarScaleMap);
> 
> // get shapes control:
> 
> ShapeControl scontrol = (ShapeControl) pBarMap.getControl();
> scontrol.setShapeSet(new Integer1DSet(1));  // only one value
> scontrol.setShapes(new VisADGeometryArray[] {pBars});
> 
> // constant map to set bar color and thickness
> 
>         ConstantMap[] PrecMaps = {new ConstantMap(0.20f, Display.Red),
>                            new ConstantMap(0.50f, Display.Green),
>                            new ConstantMap(1.0f, Display.Blue),
>                            new ConstantMap(01.50f, Display.LineWidth)};
> 
> // set reference's data
> refer_Pre = new ReferenceImpl("refer_Pre" );
> 
> refer_Pre.setData( ff_Prec  );
> 
> // add reference to display, using the constant maps
> 
> display1.addReference( refer_Pre, PrecMaps);
> 
> // show display...
> 
> I hope it works, because I cut and pasted the code above from a more
> complex application. You can see the resulting display at:
> 
> http://www.geogr.uni-jena.de/~p6taug/demviewer/more/modv.jpg
> 
> You could also use a Gridded2D (?) set (actually, and array of those),
> which is by far simpler (as Bill said, VisAD sahpes are rather complex:
> some of the credits for code above goes to Bill, anyway; especially the
> magic parts ;-)
> 
> hope it has helped clear up a bit.
> 
> Cheers,
> 
> Ugo