CorePlot - set y-Axis range to include all data points

Question

I applied the CorePlot graph in an iOS application, however, I cannot dynamically change the y axis based on the data points in the set. Some datasets range from 10 to 50, while others range from 400 to 500. In both cases, I would like to see y-origin (0).

I tried using the scaletofitplots method:

[graph.defaultPlotSpace scaleToFitPlots:[graph allPlots]]; 

but this does not affect the graphs, they still show the default Y-Axis range from 0 to 1.

The only way I can change y-Axis is to do it manually:

 graph.defaultPlotSpace.yRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(0.0f)) length:CPTDecimalFromFloat(500.0f)]; 

However, this does not work well for graphs with smaller ranges (10-50), as you can imagine.

Is there any method to get the highest y value from my dataset so that I can manually set the maximum y-axis for this value? Or is there a better alternative?

EDIT: Here is the file I am using:

 #import "TUTSimpleScatterPlot.h" @implementation TUTSimpleScatterPlot @synthesize hostingView = _hostingView; @synthesize graph = _graph; @synthesize graphData = _graphData; -(id)initWithHostingView:(CPTGraphHostingView *)hostingView andData:(NSMutableArray *)data { self = [super init]; if (self != nil) { self.hostingView = hostingView; self.graphData = data; self.graph = nil; } return self; } -(void)initialisePlot { if ((self.hostingView == nil) || (self.graphData == nil)) { NSLog(@"TUTSimpleScatterPlot: Cannot Initialise plot with hosting view and data"); return; } if (self.graph != nil) { NSLog(@"TUTSimpleScatterPlot: Graph Object already exists."); } NSDate *refDate = [NSDate date]; NSTimeInterval oneDay = 24 * 60 * 60; CGRect frame = [self.hostingView bounds]; self.graph = [[CPTXYGraph alloc] initWithFrame:frame]; CPTXYPlotSpace *plotSpace = (CPTXYPlotSpace *)self.graph.defaultPlotSpace; plotSpace.allowsUserInteraction = YES; plotSpace.delegate = self; self.graph.plotAreaFrame.paddingBottom = 20.0f; self.graph.plotAreaFrame.paddingLeft = 35.0f; self.hostingView.hostedGraph = self.graph; CPTMutableLineStyle *lineStyle = [CPTMutableLineStyle lineStyle]; lineStyle.lineColor = [CPTColor whiteColor]; lineStyle.lineWidth = 2.0f; CPTMutableLineStyle *lineStyleThin = [CPTMutableLineStyle lineStyle]; lineStyleThin.lineColor = [CPTColor whiteColor]; lineStyleThin.lineWidth = 1.0f; CPTMutableTextStyle *textStyle = [CPTMutableTextStyle textStyle]; textStyle.fontName = @"HelveticaNeue-Medium"; textStyle.fontSize = 10; textStyle.color = [CPTColor whiteColor]; CPTMutableLineStyle *plotSymbolLineStyle = [CPTMutableLineStyle lineStyle]; plotSymbolLineStyle.lineColor = [CPTColor whiteColor]; plotSymbolLineStyle.lineWidth = 1.0f; CPTPlotSymbol *plotSymbol = [CPTPlotSymbol ellipsePlotSymbol]; plotSymbol.lineStyle = plotSymbolLineStyle; plotSymbol.fill = [CPTFill fillWithColor:[CPTColor colorWithComponentRed:0.4 green:0.6 blue:0.8 alpha:1.0]]; plotSymbol.size = CGSizeMake(8.0, 8.0); CPTScatterPlot *plot = [[CPTScatterPlot alloc] init]; plot.dataSource = self; plot.identifier = @"mainPlot"; [plotSpace scaleToFitPlots:[graph allPlots]]; CPTMutablePlotRange *yRange = [plotSpace.yRange mutableCopy]; [yRange expandRangeByFactor:CPTDecimalFromDouble(615)]; plotSpace.yRange = yRange; plotSpace.xRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(oneDay - (oneDay * 6.3f)) length:CPTDecimalFromFloat(oneDay * 6.6f)]; plotSpace.allowsUserInteraction = YES; CPTPlotRange *globalYRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromDouble(0.0f) length:CPTDecimalFromDouble(615.0f)]; plotSpace.globalYRange = globalYRange; // Modify the graph axis with a label, line style, etc CPTXYAxisSet *axisSet = (CPTXYAxisSet *)self.graph.axisSet; axisSet.xAxis.axisConstraints = [CPTConstraints constraintWithLowerOffset:0.0]; axisSet.xAxis.axisLineStyle = lineStyle; axisSet.xAxis.majorTickLineStyle = lineStyle; axisSet.xAxis.labelTextStyle = textStyle; axisSet.xAxis.labelOffset = 1.0f; axisSet.xAxis.majorIntervalLength = CPTDecimalFromFloat(oneDay*1); axisSet.xAxis.orthogonalCoordinateDecimal = CPTDecimalFromString(@"0.0"); axisSet.xAxis.minorTicksPerInterval = 0; axisSet.xAxis.majorTickLength = 0.0f; axisSet.xAxis.majorGridLineStyle = majorGridLineStyle; NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; [dateFormatter setDateFormat:@"dd MMM"]; CPTTimeFormatter *timeFormatter = [[CPTTimeFormatter alloc] initWithDateFormatter:dateFormatter]; timeFormatter.referenceDate = refDate; axisSet.xAxis.labelFormatter = timeFormatter; axisSet.yAxis.axisLineStyle = lineStyle; axisSet.yAxis.majorTickLineStyle = lineStyle; axisSet.yAxis.minorTickLineStyle = lineStyleThin; axisSet.yAxis.labelTextStyle = textStyle; axisSet.yAxis.labelOffset = 3.0f; axisSet.yAxis.majorIntervalLength = CPTDecimalFromString(@"50.0"); axisSet.yAxis.minorTicksPerInterval = 1; axisSet.yAxis.minorTickLength = 3.0; axisSet.yAxis.majorTickLength = 5.0; axisSet.yAxis.orthogonalCoordinateDecimal = CPTDecimalFromFloat(0); axisSet.yAxis.majorGridLineStyle = majorGridLineStyle; axisSet.yAxis.axisConstraints = [CPTConstraints constraintWithLowerOffset:0.0]; CPTMutableLineStyle *theLineStyle = [CPTMutableLineStyle lineStyle]; theLineStyle.lineColor = [CPTColor colorWithComponentRed:0.3 green:0.6 blue:0.9 alpha:1.0]; theLineStyle.lineWidth = 2.0f; plot.dataLineStyle = theLineStyle; plot.plotSymbol = plotSymbol; [self.graph addPlot:plot]; } 

Answer 1

It looks like you are using -scaleToFitPlots: correctly. If necessary, this method will update the chart data. Before calling, make sure that the relevant data is available to the data source.

Edit based on new code:

-scaleToFitPlots: called before adding a chart to the chart. Therefore, the -allPlots array -allPlots empty and there is nothing to scale. Move the zoom operation after plotting and adding to the plot.