Displaying posts filed under

Graphing

posts related to generate graphs

Nov
26
2009

Display stock charts on your own website

Plain stock chart
In searching an easy way to display stock charts on a web page hosted in a web server, two useful scripts were found on the internet:
1. Easy Yahoo stock chart ASP.NET Page
2. Displaying a daily chart for a ticker symbol
Even the scripts were written in different languages, they use a common idea that [...]

Nov
19
2009

Gene network visualization

Cytoscape is an open source bioinformatics software platform for visualizing molecular interaction networks and biological pathways and integrating these networks with annotations, gene expression profiles and other state data. The following is a snapshot of the sowtware interface.

The current version of the software is v2.6.3. The core features of Cytoscape include data integration, visualization, and [...]

Aug
30
2009

eDigitizer user guide

As a researcher, you may encounter the following situations from time to time. You need to get original data for a graph published in a scientific paper. The simple way is to use a ruler and estimate the value of each data point by eye. If you want to get the data more accurately, you [...]

Aug
27
2009

Frequency histogram 制作频率分布图

相关函数介绍
1.FREQUENCY函数
返回指定数据和分组的频率数组。函数FREQUENCY的语法形式为:
FREQUENCY(data_array,bins_array)
其中Data_array为一数组或对一组数值的引用,用来计算频率。如果 data_array 中不包含任何数值,函数FREQUENCY返回零数组。Bins_array为一数组或对数组区域的引用,设定对data_array进行频率计算的分段点。如果bins_array中不包含任何数值,函数FREQUENCY返回data_array元素的数目。
看起来FREQUENCY的用法蛮复杂的,但其用处很大。比如可以计算不同工资段的人员分布,公司员工的年龄分布,学生成绩的分布,不同品种的产量分布情况等。这里以具体示例说明其基本的用法。
2.NORMDIST函数
返回给定平均值和标准偏差的正态分布的累积函数。函数的语法为:
NORMDIST(x,mean,standard_dev,cumulative)
x是需要计算累计概率的数据,mean为平均值,standard_dev为标准差,cumulative可以使TRUE或FALSE,当计算累计概率时取TRUE。
应用实例
例1、计算员工年龄分布情况
1)在工作表里第一列(A2:A9)输入员工的年龄,数据为28、25、31、21、44、33、22和35;
2)在C2:C5单元格中输入25、30、35、和40;
3)选择D2:D6单元格,输入=FREQUENCY(a2:a9,c2:c5),按CTRL+SHIFT+ENTER输入数组。
这样就可以计算出年龄在25岁以下、26~30岁、31~35岁、36~40岁和40岁以上各区间中的数目。本例中选择了5个垂直相邻的单元格后,即以数组方式输入公式。返回的数组中的元素个数比bins_array(数组中的元素个数多1。第五个数字1表示大于最高间隔(40)的数值(44)的个数。函数FREQUENCY忽略空白单元格和文本值。该例在age工作表中。
例2、在处理科学试验结果时,我们往往希望看看试验数据是否符合正态分布,最简单的办法是做频率分布图。本例中生成100个随机数字,然后对这些数据做频率分布图。
1)EXCEL提供了一个数据分析包(Analysis toolpak),打开该分析包的方法是使用ADD-INS菜单命令。
2)使用菜单命令Tools|Data Analysis…,在弹出菜单中选中”Random Number Generation”,完成对话框中的相应输入框,在A2:A101单元格中生成100个随机数字。
3)命名A2:A101为data;
4)计算数据的平均值和标准差,在D1和D2中分别输入=AVERAGE(data)和=STDEV(data);
5)在C5:C17中输入8.50到11.50,以0.50为间隔,这就是Bins_array;
6)选择D5:D17,输入=frequency(data,c5:c17)并按CTRL+SHIFT+ENTER输入该公式;
7)计算总频率数,在D18中输入=sum(d5:d17);
8)计算期望频率,在E5中输入=$d$18*normdist(c5,mean,stdev,true),在E6中输入=$d$18*(normdist(c6,mean,stdev,true)-normdist(c5-mean,stdev,true)),使用向下填充直到E16,在E17中输入=$d$18*(1-normdist(c16,mean,stdev,true));
在E5中计算数据小于等于8.5的累计概率,在E6-E16中两个连续数据(一组)的期望频率,在E17中计算数据大与等于11.5的累计概率;
9)计算期望频率的总和,在D18中输入=sum(e5:e17).
10)制作频率分布图:选中D5:E17,做一个连线图(Line),单击’Series’标签,在’Category(X) axis labels’中选中C5:C17,等图形完成后,选中实际数据线,单击鼠标右键,在弹出的右键菜单中选中’Chart type’,将其设置成柱状图(Cloumn),并设置间隙为0;并格式化Normal数据为平滑曲线。

[...]

Aug
26
2009

Graph Digitization in MATLAB

Sometimes we need digitize graphs from scientific papers because we can not get the original data. The digitized data can be used to fit model or redraw graphs. How can we achieve the goal? At the beginning I think we can do that by reading the image data and classifying the data by a given [...]

Aug
24
2009

Using R to create brick block graphs

R provides powerful graphics functions. We can use it to draw very complicated and beautiful graphs. Here provides a complete solution to draw brick block graph in R. The function name is brickblock that takes a matrix, graph height, a vector of x-labels, and groupname as inputs. The length of vector should be same as [...]

Aug
19
2009

Data visualization and outlier detection

Any dataset can potentially have outliers. To get good results through statistical analysis, outliers should be always excluded. There are multiple ways to do that. One way is to create box whisker plot and visually and manually find them.
Basic concept
What do the box and whiskers represent in box whisker plot? The box represents the [...]

Aug
18
2009

Automate PowerPoint Slide Creation

One time I have to generate a lot of graphs on fly and insert them to PowerPoint slides to create a nice presentation. The situation is that I have to repeat this process again and again every week or days. The graphs generated on fly are a fixed set. Nobody want to do this boring [...]

Aug
18
2009

Dynamic graphing in Excel

Problem:
Data are in two columns: A and B.  I am plotting a graph which takes data from columns  A and B as its source data. I want to generate an Excel template that can use many times. That is, I can copy data to the data sheet and view graph directly. The number of rows in [...]

Aug
18
2009

eDigitizer – a Windows application to digitize graphs

Introduction
eDigitizer is a powerful tool that can help users to digitize the data points in graphs. It is extremely useful to scientists and engineers who are trying to use data from scientific literature in their study. Click here to see a screen shot. Main features of eDigitizer include the following:

Process multiple image formats
Stretch, zoom, center [...]