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.
[Web Version (in ASP)] aspdemo\contourinterpolate.asp
<%@ language="vbscript" %>
<%
Set cd = CreateObject("ChartDirector.API")
' This script can draw different charts depending on the chartIndex
Sub createChart(viewer, chartIndex)
' The x and y coordinates of the grid
dataX = Array(-4, -3, -2, -1, 0, 1, 2, 3, 4)
dataY = Array(-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).
ReDim dataZ((UBound(dataX) + 1) * (UBound(dataY) + 1) - 1)
For yIndex = 0 To UBound(dataY)
y = dataY(yIndex)
For xIndex = 0 To UBound(dataX)
x = dataX(xIndex)
dataZ(yIndex * (UBound(dataX) + 1) + xIndex) = Sin(x * 3.1416 / 3) * Sin(y * 3.1416 /3)
Next
Next
' Create a XYChart object of size 360 x 360 pixels
Set c = cd.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
Call c.setPlotArea(30, 25, 300, 300, -1, -1, -1, &Hc0000000, -1)
' Add a contour layer using the given data
Set layer = c.addContourLayer(dataX, dataY, dataZ)
' Set the x-axis and y-axis scale
Call c.xAxis().setLinearScale(-4, 4, 1)
Call c.yAxis().setLinearScale(-4, 4, 1)
If chartIndex = 0 Then
' Discrete coloring, spline surface interpolation
Call c.addTitle("Spline Surface - Discrete Coloring", "Arial Bold Italic", 12)
ElseIf chartIndex = 1 Then
' Discrete coloring, linear surface interpolation
Call c.addTitle("Linear Surface - Discrete Coloring", "Arial Bold Italic", 12)
Call layer.setSmoothInterpolation(False)
ElseIf chartIndex = 2 Then
' Smooth coloring, spline surface interpolation
Call c.addTitle("Spline Surface - Continuous Coloring", "Arial Bold Italic", 12)
Call layer.setContourColor(cd.Transparent)
Call layer.colorAxis().setColorGradient(True)
Else
' Discrete coloring, linear surface interpolation
Call c.addTitle("Linear Surface - Continuous Coloring", "Arial Bold Italic", 12)
Call layer.setSmoothInterpolation(False)
Call layer.setContourColor(cd.Transparent)
Call layer.colorAxis().setColorGradient(True)
End If
' Output the chart
Call viewer.setChart(c, cd.SVG)
End Sub
' This example includes 4 charts
Dim viewers(3)
For i = 0 To Ubound(viewers)
Set viewers(i) = cd.WebChartViewer(Request, "chart" & i)
Call createChart(viewers(i), i)
Next
%>
<!DOCTYPE html>
<html>
<head>
<title>Contour Interpolation</title>
<!-- Include ChartDirector Javascript Library to support chart interactions -->
<script type="text/javascript" src="cdjcv.js"></script>
</head>
<body style="margin:5px 0px 0px 5px">
<div style="font:bold 18pt verdana;">
Contour Interpolation
</div>
<hr style="border:solid 1px #000080; background:#000080" />
<div style="font:10pt verdana; margin-bottom:1.5em">
<a href="viewsource.asp?file=<%= Request("SCRIPT_NAME") %>">View Chart Source Code</a>
</div>
<!-- ****** Here are the chart images ****** -->
<%
For i = 0 To Ubound(viewers)
Call Response.Write(viewers(i).renderHTML())
Call Response.Write(" ")
Next
%>
</body>
</html>
[Windows Version (in Visual Basic)] vbdemo\contourinterpolate.cls
Public Sub createChart(viewer As Object, chartIndex As Integer)
Dim cd As New ChartDirector.API
' The x and y coordinates of the grid
Dim dataX()
dataX = Array(-4, -3, -2, -1, 0, 1, 2, 3, 4)
Dim dataY()
dataY = Array(-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).
ReDim dataZ((UBound(dataX) + 1) * (UBound(dataY) + 1) - 1)
Dim yIndex As Long
For yIndex = 0 To UBound(dataY)
Dim y As Double
y = dataY(yIndex)
Dim xIndex As Long
For xIndex = 0 To UBound(dataX)
Dim x As Double
x = dataX(xIndex)
dataZ(yIndex * (UBound(dataX) + 1) + xIndex) = Sin(x * 3.1416 / 3) * Sin(y * 3.1416 /3)
Next
Next
' Create a XYChart object of size 360 x 360 pixels
Dim c As XYChart
Set c = cd.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
Call c.setPlotArea(30, 25, 300, 300, -1, -1, -1, &Hc0000000, -1)
' Add a contour layer using the given data
Dim layer As ContourLayer
Set layer = c.addContourLayer(dataX, dataY, dataZ)
' Set the x-axis and y-axis scale
Call c.xAxis().setLinearScale(-4, 4, 1)
Call c.yAxis().setLinearScale(-4, 4, 1)
If chartIndex = 0 Then
' Discrete coloring, spline surface interpolation
Call c.addTitle("Spline Surface - Discrete Coloring", "arialbi.ttf", 12)
ElseIf chartIndex = 1 Then
' Discrete coloring, linear surface interpolation
Call c.addTitle("Linear Surface - Discrete Coloring", "arialbi.ttf", 12)
Call layer.setSmoothInterpolation(False)
ElseIf chartIndex = 2 Then
' Smooth coloring, spline surface interpolation
Call c.addTitle("Spline Surface - Continuous Coloring", "arialbi.ttf", 12)
Call layer.setContourColor(cd.Transparent)
Call layer.colorAxis().setColorGradient(True)
Else
' Discrete coloring, linear surface interpolation
Call c.addTitle("Linear Surface - Continuous Coloring", "arialbi.ttf", 12)
Call layer.setSmoothInterpolation(False)
Call layer.setContourColor(cd.Transparent)
Call layer.colorAxis().setColorGradient(True)
End If
' Output the chart
Set viewer.Picture = c.makePicture()
End Sub
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