Workshop 3: Charts

A picture is worth thousand words Trying to draw information from numerical data takes time and is painful We can use graphical representation to give quick overview of information

A picture is worth thousand words Let’s take a look of our previous exercise for an instance. IMPORTANT!! Graphical representation is good for briefing / overview It is not as precise as numerical data Always use correct type to represent data Use together with numerical data, if it is necessary It needs to be clear and must NOT be fancy

Exercise We’ll create a chart from air quality table from previous exercise source: Step 1: select all data including header Step 2: click chart wizard icon Step 3: Choose chart type  Line  click Next http://www.pcd.go.th/AirQuality/Regional/defaultThai.cfm

Exercise Step 4: Fill the chart title and axis  click Next  Finish

Fine tuning your chart Some lines are too close to the axis due to their scale These lines are useless since they cannot give any information We need to enlarge them by adjusting vertical scale

Fine tuning your chart Linear scale is not suitable for our chart since it compresses some data series Let’s try log scale on vertical axis Right click exactly on the vertical scale, then choose “Format Axis…” Choose “Scale” tab in the Format Axis dialog, then check the Log scale box

Fine tuning your chart In the chart, we can change: Line color and thickness Chart background color Legend types Legend placement Label alignment Add trend lines Add grid lines

- 4 < x < 4 Basic Scientific Plots cos(x) x*cos(x) sin(x) / x Usually generated from a mathematical functions Exercise: plot curves of the following functions on the same chart sin(x) cos(x) x*cos(x) sin(x) / x - 4 < x < 4