ChartDirector 6.2 (.NET Edition)

Contour Interpolation

This example demonstrates spline and linear surface interpolation, and discrete and continuous coloring for the ContourLayer.

The input to the contour layer are the z values at certain (x, y) points. To draw the contour and to color the layer, it is necessarily to know the z values at all pixels in the xy plane. ChartDirector uses surface interpolation to compute the z values at all pixels from the given data points. Two types of interpolation - spline and linear - are supported. They can be configured using ContourLayer.setSmoothInterpolation.

The coloring of the contour layer can be discrete or continuous, configurable using ColorAxis.setColorGradient or ColorAxis.setColorScale.

Source Code Listing

[Windows Forms - C# version] NetWinCharts\CSharpWinCharts\contourinterpolate.cs
 ```using System; using ChartDirector; namespace CSharpChartExplorer { public class contourinterpolate : DemoModule { //Name of demo module public string getName() { return "Contour Interpolation"; } //Number of charts produced in this demo module public int getNoOfCharts() { return 4; } //Main code for creating charts public void createChart(WinChartViewer viewer, int chartIndex) { // The x and y coordinates of the grid double[] dataX = {-4, -3, -2, -1, 0, 1, 2, 3, 4}; double[] dataY = {-4, -3, -2, -1, 0, 1, 2, 3, 4}; // The values at the grid points. In this example, we will compute the values using the // formula z = Sin(x * pi / 3) * Sin(y * pi / 3). double[] dataZ = new double[dataX.Length * dataY.Length]; for(int yIndex = 0; yIndex < dataY.Length; ++yIndex) { double y = dataY[yIndex]; for(int xIndex = 0; xIndex < dataX.Length; ++xIndex) { double x = dataX[xIndex]; dataZ[yIndex * dataX.Length + xIndex] = Math.Sin(x * 3.1416 / 3) * Math.Sin(y * 3.1416 / 3); } } // Create a XYChart object of size 360 x 360 pixels XYChart c = new XYChart(360, 360); // Set the plotarea at (30, 25) and of size 300 x 300 pixels. Use semi-transparent black // (c0000000) for both horizontal and vertical grid lines c.setPlotArea(30, 25, 300, 300, -1, -1, -1, unchecked((int)0xc0000000), -1); // Add a contour layer using the given data ContourLayer layer = c.addContourLayer(dataX, dataY, dataZ); // Set the x-axis and y-axis scale c.xAxis().setLinearScale(-4, 4, 1); c.yAxis().setLinearScale(-4, 4, 1); if (chartIndex == 0) { // Discrete coloring, spline surface interpolation c.addTitle("Spline Surface - Discrete Coloring", "Arial Bold Italic", 12); } else if (chartIndex == 1) { // Discrete coloring, linear surface interpolation c.addTitle("Linear Surface - Discrete Coloring", "Arial Bold Italic", 12); layer.setSmoothInterpolation(false); } else if (chartIndex == 2) { // Smooth coloring, spline surface interpolation c.addTitle("Spline Surface - Continuous Coloring", "Arial Bold Italic", 12); layer.setContourColor(Chart.Transparent); layer.colorAxis().setColorGradient(true); } else { // Discrete coloring, linear surface interpolation c.addTitle("Linear Surface - Continuous Coloring", "Arial Bold Italic", 12); layer.setSmoothInterpolation(false); layer.setContourColor(Chart.Transparent); layer.colorAxis().setColorGradient(true); } // Output the chart viewer.Chart = c; } } }```

[Windows Forms - VB Version] NetWinCharts\VBNetWinCharts\contourinterpolate.vb
 ```Imports System Imports Microsoft.VisualBasic Imports ChartDirector Public Class contourinterpolate Implements DemoModule 'Name of demo module Public Function getName() As String Implements DemoModule.getName Return "Contour Interpolation" End Function 'Number of charts produced in this demo module Public Function getNoOfCharts() As Integer Implements DemoModule.getNoOfCharts Return 4 End Function 'Main code for creating charts Public Sub createChart(viewer As WinChartViewer, chartIndex As Integer) _ Implements DemoModule.createChart ' The x and y coordinates of the grid Dim dataX() As Double = {-4, -3, -2, -1, 0, 1, 2, 3, 4} Dim dataY() As Double = {-4, -3, -2, -1, 0, 1, 2, 3, 4} ' The values at the grid points. In this example, we will compute the values using the ' formula z = Sin(x * pi / 3) * Sin(y * pi / 3). Dim dataZ((UBound(dataX) + 1) * (UBound(dataY) + 1) - 1) As Double For yIndex As Integer = 0 To UBound(dataY) Dim y As Double = dataY(yIndex) For xIndex As Integer = 0 To UBound(dataX) Dim x As Double = dataX(xIndex) dataZ(yIndex * (UBound(dataX) + 1) + xIndex) = Math.Sin(x * 3.1416 / 3) * _ Math.Sin(y * 3.1416 / 3) Next Next ' Create a XYChart object of size 360 x 360 pixels Dim c As XYChart = New XYChart(360, 360) ' Set the plotarea at (30, 25) and of size 300 x 300 pixels. Use semi-transparent black ' (c0000000) for both horizontal and vertical grid lines c.setPlotArea(30, 25, 300, 300, -1, -1, -1, &Hc0000000, -1) ' Add a contour layer using the given data Dim layer As ContourLayer = c.addContourLayer(dataX, dataY, dataZ) ' Set the x-axis and y-axis scale c.xAxis().setLinearScale(-4, 4, 1) c.yAxis().setLinearScale(-4, 4, 1) If chartIndex = 0 Then ' Discrete coloring, spline surface interpolation c.addTitle("Spline Surface - Discrete Coloring", "Arial Bold Italic", 12) ElseIf chartIndex = 1 Then ' Discrete coloring, linear surface interpolation c.addTitle("Linear Surface - Discrete Coloring", "Arial Bold Italic", 12) layer.setSmoothInterpolation(False) ElseIf chartIndex = 2 Then ' Smooth coloring, spline surface interpolation c.addTitle("Spline Surface - Continuous Coloring", "Arial Bold Italic", 12) layer.setContourColor(Chart.Transparent) layer.colorAxis().setColorGradient(True) Else ' Discrete coloring, linear surface interpolation c.addTitle("Linear Surface - Continuous Coloring", "Arial Bold Italic", 12) layer.setSmoothInterpolation(False) layer.setContourColor(Chart.Transparent) layer.colorAxis().setColorGradient(True) End If ' Output the chart viewer.Chart = c End Sub End Class```

[WPF - C#] NetWPFCharts\contourinterpolate.cs
 ```using System; using ChartDirector; namespace CSharpWPFDemo { public class contourinterpolate : DemoModule { //Name of demo module public string getName() { return "Contour Interpolation"; } //Number of charts produced in this demo module public int getNoOfCharts() { return 4; } //Main code for creating charts public void createChart(WPFChartViewer viewer, int chartIndex) { // The x and y coordinates of the grid double[] dataX = {-4, -3, -2, -1, 0, 1, 2, 3, 4}; double[] dataY = {-4, -3, -2, -1, 0, 1, 2, 3, 4}; // The values at the grid points. In this example, we will compute the values using the // formula z = Sin(x * pi / 3) * Sin(y * pi / 3). double[] dataZ = new double[dataX.Length * dataY.Length]; for(int yIndex = 0; yIndex < dataY.Length; ++yIndex) { double y = dataY[yIndex]; for(int xIndex = 0; xIndex < dataX.Length; ++xIndex) { double x = dataX[xIndex]; dataZ[yIndex * dataX.Length + xIndex] = Math.Sin(x * 3.1416 / 3) * Math.Sin(y * 3.1416 / 3); } } // Create a XYChart object of size 360 x 360 pixels XYChart c = new XYChart(360, 360); // Set the plotarea at (30, 25) and of size 300 x 300 pixels. Use semi-transparent black // (c0000000) for both horizontal and vertical grid lines c.setPlotArea(30, 25, 300, 300, -1, -1, -1, unchecked((int)0xc0000000), -1); // Add a contour layer using the given data ContourLayer layer = c.addContourLayer(dataX, dataY, dataZ); // Set the x-axis and y-axis scale c.xAxis().setLinearScale(-4, 4, 1); c.yAxis().setLinearScale(-4, 4, 1); if (chartIndex == 0) { // Discrete coloring, spline surface interpolation c.addTitle("Spline Surface - Discrete Coloring", "Arial Bold Italic", 12); } else if (chartIndex == 1) { // Discrete coloring, linear surface interpolation c.addTitle("Linear Surface - Discrete Coloring", "Arial Bold Italic", 12); layer.setSmoothInterpolation(false); } else if (chartIndex == 2) { // Smooth coloring, spline surface interpolation c.addTitle("Spline Surface - Continuous Coloring", "Arial Bold Italic", 12); layer.setContourColor(Chart.Transparent); layer.colorAxis().setColorGradient(true); } else { // Discrete coloring, linear surface interpolation c.addTitle("Linear Surface - Continuous Coloring", "Arial Bold Italic", 12); layer.setSmoothInterpolation(false); layer.setContourColor(Chart.Transparent); layer.colorAxis().setColorGradient(true); } // Output the chart viewer.Chart = c; } } }```

[ASP.NET Web Forms - C# version] NetWebCharts\CSharpASP\contourinterpolate.aspx
 ```<%@ Page Language="C#" Debug="true" %> <%@ Import Namespace="ChartDirector" %> <%@ Register TagPrefix="chart" Namespace="ChartDirector" Assembly="netchartdir" %> ```

[ASP.NET Web Forms - VB Version] NetWebCharts\VBNetASP\contourinterpolate.aspx
 ```<%@ Page Language="VB" Debug="true" %> <%@ Import Namespace="ChartDirector" %> <%@ Register TagPrefix="chart" Namespace="ChartDirector" Assembly="netchartdir" %> ```
 ```using System; using System.Web.Mvc; using ChartDirector; namespace NetMvcCharts.Controllers { public class ContourinterpolateController : Controller { // // Default Action // public ActionResult Index() { ViewBag.Title = "Contour Interpolation"; // This example contains 4 charts. ViewBag.Viewer = new RazorChartViewer[4]; for (int i = 0; i < ViewBag.Viewer.Length; ++i) createChart(ViewBag.Viewer[i] = new RazorChartViewer(HttpContext, "chart" + i), i); return View("~/Views/Shared/ChartView.cshtml"); } // // Create chart // private void createChart(RazorChartViewer viewer, int chartIndex) { // The x and y coordinates of the grid double[] dataX = {-4, -3, -2, -1, 0, 1, 2, 3, 4}; double[] dataY = {-4, -3, -2, -1, 0, 1, 2, 3, 4}; // The values at the grid points. In this example, we will compute the values using the // formula z = Sin(x * pi / 3) * Sin(y * pi / 3). double[] dataZ = new double[dataX.Length * dataY.Length]; for(int yIndex = 0; yIndex < dataY.Length; ++yIndex) { double y = dataY[yIndex]; for(int xIndex = 0; xIndex < dataX.Length; ++xIndex) { double x = dataX[xIndex]; dataZ[yIndex * dataX.Length + xIndex] = Math.Sin(x * 3.1416 / 3) * Math.Sin(y * 3.1416 / 3); } } // Create a XYChart object of size 360 x 360 pixels XYChart c = new XYChart(360, 360); // Set the plotarea at (30, 25) and of size 300 x 300 pixels. Use semi-transparent black // (c0000000) for both horizontal and vertical grid lines c.setPlotArea(30, 25, 300, 300, -1, -1, -1, unchecked((int)0xc0000000), -1); // Add a contour layer using the given data ContourLayer layer = c.addContourLayer(dataX, dataY, dataZ); // Set the x-axis and y-axis scale c.xAxis().setLinearScale(-4, 4, 1); c.yAxis().setLinearScale(-4, 4, 1); if (chartIndex == 0) { // Discrete coloring, spline surface interpolation c.addTitle("Spline Surface - Discrete Coloring", "Arial Bold Italic", 12); } else if (chartIndex == 1) { // Discrete coloring, linear surface interpolation c.addTitle("Linear Surface - Discrete Coloring", "Arial Bold Italic", 12); layer.setSmoothInterpolation(false); } else if (chartIndex == 2) { // Smooth coloring, spline surface interpolation c.addTitle("Spline Surface - Continuous Coloring", "Arial Bold Italic", 12); layer.setContourColor(Chart.Transparent); layer.colorAxis().setColorGradient(true); } else { // Discrete coloring, linear surface interpolation c.addTitle("Linear Surface - Continuous Coloring", "Arial Bold Italic", 12); layer.setSmoothInterpolation(false); layer.setContourColor(Chart.Transparent); layer.colorAxis().setColorGradient(true); } // Output the chart viewer.Image = c.makeWebImage(Chart.JPG); } } }```
 ```@{ Layout = null; } @ViewBag.Title