Programming language: Java
Topic: Plots/Contour
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/*
*/

// Import needed classes

import java.rmi.RemoteException;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import jhplot.*;

/**
VisAD Tutorial example with denser contours
We have the function temperature = f(latitude, longitude)
represented by the MathType
( (latitude, longitude) -> elevation )
Use ContourControl
*/

// Declare variables
// The domain quantities longitude and latitude
// and the dependent quantity temperature

private RealType longitude, latitude;
private RealType temperature;

// Tuple to pack longitude and latitude together, as the domain
private RealTupleType domain_tuple;

// The function (domain_tuple -> temperature )
// Remeber, range is only "temperature"
private FunctionType func_domain_range;

// Our Data values for the domain are represented by the Set
private Set domain_set;

// The Data class FlatField
private FlatField vals_ff;

// The DataReference from data to display
private DataReferenceImpl data_ref;

// The 2D display, and its the maps
private DisplayImpl display;
private ScalarMap latMap, lonMap;
private ScalarMap tempIsoMap, tempRGBMap;

// get 2D display
display = c1.getDisplay();

// Create the quantities
// Use RealType(String name);
latitude = RealType.getRealType("latitude");
longitude = RealType.getRealType("longitude");

domain_tuple = new RealTupleType(latitude, longitude);

temperature = RealType.getRealType("temperature");

// Create a FunctionType (domain_tuple -> temperature )
// Use FunctionType(MathType domain, MathType range)
func_domain_range = new FunctionType( domain_tuple, temperature);

// Create the domain Set
// Use LinearDSet(MathType type, double first1, double last1, int lengthX,
//				     double first2, double last2, int lengthY)

int NCOLS = 50;
int NROWS = NCOLS;

domain_set = new Linear2DSet(domain_tuple, -Math.PI, Math.PI, NROWS,
-Math.PI, Math.PI, NCOLS);

// Get the Set samples to facilitate the calculations
float[][] set_samples = domain_set.getSamples( true );

// The actual temperature values are stored in this array
// float[1][ number_of_samples ]
float[][] flat_samples = new float[1][NCOLS * NROWS];

// We fill our 'flat' array with the generated values
// by looping over NCOLS and NROWS
for(int c = 0; c < NCOLS; c++)

for(int r = 0; r < NROWS; r++){

// ...temperature
flat_samples[0][ c * NROWS + r ] = (float)( (Math.sin( 0.50*(double) set_samples[0][ c * NROWS + r ])  ) * Math.cos( (double) set_samples[1][ c * NROWS + r ] ) ) ;

}

// Create a FlatField
// Use FlatField(FunctionType type, Set domain_set)
vals_ff = new FlatField( func_domain_range, domain_set);

// ...and put the values above into it
// Note the argument false, meaning that the array won't be copied
vals_ff.setSamples( flat_samples , false );

// Create Display and its maps
// Get display's graphics mode control and draw scales
GraphicsModeControl dispGMC = (GraphicsModeControl)  display.getGraphicsModeControl();
dispGMC.setScaleEnable(true);

// Create the ScalarMaps: latitude to YAxis, longitude to XAxis and
// temperature to IsoContour and eventualy to RGB
// Use ScalarMap(ScalarType scalar, DisplayRealType display_scalar)
latMap = new ScalarMap( latitude,    Display.YAxis );
lonMap = new ScalarMap( longitude, Display.XAxis );
tempIsoMap = new ScalarMap( temperature,  Display.IsoContour );
tempRGBMap = new ScalarMap( temperature,  Display.RGB );

// The ContourControl
// Note that we get the control from the IsoContour map
ContourControl isoControl = (ContourControl) tempIsoMap.getControl();

// Define some parameters for contour lines

float interval = 0.1250f;  // interval between lines
float lowValue = -0.50f;   // lowest value
float highValue = 1.0f;    // highest value
float base = -1.0f;        //  starting at this base value

// ...and set the lines with the method
isoControl.setContourInterval(interval, lowValue, highValue, base);
isoControl.enableLabels(true);

// why not try to fill the contours? uncomment as needed
// note: labels won't be draw and there must be the maps
// someRealType -> IsoContour AND
// someRealType -> RGB
//isoControl.setContourFill(true);

// Create a data reference and set the FlatField as our data
data_ref = new DataReferenceImpl("data_ref");
data_ref.setData( vals_ff );

// show it
c1.visible(true);

}

public static void main(String[] args)