Bubble chart

[tony]

hi,

How to change the range for z Axis in bubble.
The problem now is bubbles in my chart are entirely covering my chart.
I just wanted to reduce the scale for z-Axis.


Thanks,
tony

[david.gilbert]

You'll need to scale the z-values in your dataset, since the size of the bubbles is taken from the z-value but displayed relative to the x and y axes.

[gaea]

how to scale the the z axis value . for the same dataset i m having perfect chart in excel .but in jfree bubble chart ,the size of the bubble doesnt fits perfect.

i found that if the difference b/w the largest value and the smallest on either the domain or range axis is too large ,then my bubbles are bad.


plz any one post the answer.....

[david.gilbert]

I don't have Excel, so perhaps you could post a sample dataset and the resulting chart from Excel so I could see what the difference is.

[gaea]

much happy at ur reply.

here s my dataset .though the variation are too much .still i m getting good bubbles in excel.
but jfree does not.

i have set my ranges dynamically from min and max values of the domain and range axis.

my dataset



x y z
6.02 17.14 93.46
9.8 43.8 118.928
18.53 0.1 13.83
25.02 1.5 6.05
14.78 499.6 3.2
13.479 -7.4 16.404

[gaea]

x ------------------ y ---------------------------------z
6.02------------------- 17.14------------------------------ 93.46
9.8 ---------------------43.8----------------------------- 118.928
18.53 ------------------0.1 ---------------------------------13.83
25.02 ---------------1.5------------------------------------- 6.05
14.78---------------- 499.6--------------------------------- 3.2
13.479 ----------------(-7.4)------------------------------- 16.404


how can i scale the z-axis range values relative to domain or range axis value

[wzwei28]

JFreeChart 1.0.10 and 1.0.11
The equation is quite simple.(XYZDataset, DefaultXYZDataset)

When we instantiate renderer for bubble chart. We declare as follow:
XYItemRenderer xyItemRendererBubble = new XYBubbleRenderer(XYBubbleRenderer.SCALE_ON_BOTH_AXIS);
XYItemRenderer xyItemRendererBubble = new XYBubbleRenderer(XYBubbleRenderer.SCALE_ON_DOMAIN_AXIS);
XYItemRenderer xyItemRendererBubble = new XYBubbleRenderer(XYBubbleRenderer.SCALE_ON_RANGE_AXIS);
or
XYItemRenderer xyItemRendererBubble = new XYBubbleRenderer(); //default SCALE_ON_BOTH_AXIS

Let's us open the XYBubbleRenderer class at package org.jfree.chart.renderer.xy
Goto method: public void drawItem(Graphics2D g2, ...etc.)
At swtich(getScaleType()), u will observe 3 case: SCALE_ON_DOMAIN_AXIS, SCALE_ON_RANGE_AXIS and default
default equal to SCALE_ON_BOTH_AXIS.

In this example, I use SCALE_ON_RANGE_AXIS as sample, cause relative easy to understand.
In ur chart, on range-axis maybe form by 100. And it divide into 10 dotted lines which 1 interval is 10.
Then, when u Want to draw a bubble which the Z-value (equal to diameter of bubble=2 radius).
If diameter = 10, then the z-value for the seriesItem should be 10.0 If u dataset range axis is 10000,
then u want a bubble conquer 10% of the chart range, the z-axis(diameter) should be 1000 indeed.
*To automatic calculate to fit the best z-value on various chart type. U will need a double value called dRatio.

dZ * dRatio will equal to the Z-value if in SCALE_ON_RANGE_AXIS type.
How to determine dRatio? U may use ur talented brain to think about it.
(CLUE:based on dataset on different stock)

Pretty easy, ya?