Concepts and Definitions

ChartMechanic Overview
Data Source
Types
Chart
Resource Persistence

ChartMechanic Overview

ChartMechanic is a repository of structured and semi-structured data from across the web, and from within your enterprise. Data is fetched, validated, scrubbed, and kept up-to-date. With a broad collection of data from many heterogeneous sources aggregated into one repository, it is now simpler than ever to create compelling analysis, reports, and charts.

Data Source

A data source specifies a source of values that can be represented graphically in a chart. The raw data, i.e., the actual provider of the data, can be one of the following formats:

• Spreadsheet
• Microsoft Excel
• Google Spreadsheets
• CSV: comma separated values file
• HTML: tables from web pages
• manually typed or cut/paste data

In ChartMechanic, a data source is a logical specification that contains the location of the raw data as well as information about the columns and rows of the data. The location of the raw data can be an external URL to any location on the Internet (e.g. starts with "http:"). Alternatively, the raw data can be uploaded to the ChartMechanic server and stored in ChartMechanic's Virtual File System (VFS).

Tabular, typed data is needed to create a chart. When specifying a data source, you can set the types of the columns as well as the beginning and end rows of the data you want. By customizing a data source with different column and row settings, you can create multiple data sources that point to the same underlying raw data but refer to different areas of data. For example, multiple data sources can be created that refer to different sheets or different regions within the same spreadsheet workbook.

Learn more about data sources...

Types

ChartMechanic understands data in three basic types:

• DATE - Time-based values. Many charts are time-related and time values are commonly used in the X-axis
• NUMBER - Integer or decimal values. Number typed values are most frequently used as the Y-axis values in charts
• TEXT - String or alphanumeric values. Text typed values are commonly used as categories in pie charts or bar charts.

Tabular Typed Data Example
DATE	TEXT	NUMBER
2009-02	Composite	166.8
2009-02	Boston	156.0
2009-02	Chicago	144.2
2009-02	Denver	127.0
2009-02	Las Vegas	139.0
2009-02	Los Angeles	172.2
2009-02	Miami	171.0
2009-02	New York	188.0
2009-02	San Diego	153.0
2009-02	San Francisco	139.8
2009-02	Washington DC	179.0

Learn more about data types...

Chart

A chart is a visual representation of one or more tabular data sets. The primary function of ChartMechanic is to allow you to easily build and customize charts from a variety of data sources.

Charts come in many forms and can contain various kinds of plots. The plot types supported by ChartMechanic include:

• Time Series Time series plots are like XY plots except the X axis is a Date value.
• XY XY plots graph numeric values along a two-dimensional coordinate system.
• Category Category plots show values based on Text-typed values. A common example is a bar chart where each bar corresponds to a string category and the height of the bar corresponds to the numeric value for that category.
• Gantt Gantt charts show duration of various categories against time on the X-axis.
• Pie Pie charts are a special kind of category chart that displays each category as a pie slice. In this way, the relative values of the categories can be easily compared. Pie charts can also be show in 3D as well as ring plots. Ring plots are like pie charts except that are missing the middle section
• Histogram Histogram plots show a frequency distribution of values along a spectrum of possible values

Chart & Data Compatibility
Chart Type	X Axis Type	Y Axis Type
Time Series	DATE	NUMBER
XY	NUMBER	NUMBER
Category	ANY	NUMBER
Pie	ANY	NUMBER
Histogram	N/A	NUMBER
Gantt	ANY	DATE

ChartMechanic allows you to customize your chart with different fonts, colors, shapes, axes, legends, etc. After a chart is created, it can also be displayed in a variety formats including as a image, as a PDF file, and as a Postscript file. Most commonly, a chart is displayed as a image on a web page. ChartMechanic provides you durable, bookmark-able links to chart images. One of the features of ChartMechanic is to automatically refresh the chart image when the underlying data changes.

Learn more about charts...

Resource Persistence

ChartMechanic stores all the charts and data sources you have created within an internal file system on the server. Every user has a directory tree within this Virtual File System (VFS) where charts and data can be stored. ChartMechanic supports the uploading of raw data. You may upload images, CSV values and Excel spreadsheets to be used in your charts.

You can control whether others can see your charts and data sources by changing the access level from public to private.

Learn more about persistence...