What is a spaghetti plot? Spaghetti plots are line plots that involve many overlapping lines. Like spaghetti on your plate, they can be hard to unravel, yet for many analysts they are a delicious staple of data visualization. This article presents the good, the bad, and the messy about spaghetti
When I read Robert Allison's article about the cost of a taxi ride in New York City, I was struck by the scatter plot (shown at right; click to enlarge) that plots the tip amount against the total bill for 12 million taxi rides. The graph clearly reveals diagonal and
The SG procedures in SAS use aesthetically pleasing default colors, shapes, and styles, but sometimes it is necessary to override the default attributes. The MARKERATTRS= option enables you to override the default colors, symbols, and sizes of markers in scatter plots and other graphs. Similarly, the LINEATTRS= option enables you
You can use histograms to visualize the distribution of data. A comparative histogram enables you to compare two or more distributions, which usually represent subpopulations in the data. Common subpopulations include males versus females or a control group versus an experimental group. There are two common ways to construct a
Last week Sanjay Matange wrote about a new SAS 9.4m3 option that enables you to show all categories in a graph legend, even when the data do not contain all the categories. Sanjay's example was a chart that showed medical conditions classified according to the scale "Mild," "Moderate," and "Severe."
In SAS, the aspect ratio of a graph is the physical height of the graph divided by the physical width. Recently I demonstrated how to set the aspect ratio of graphs in SAS by using the ASPECT= option in PROC SGPLOT or by using the OVERLAYEQUATED statement in the Graph
I began 2016 by compiling a list of popular articles from my blog in 2015. This "People's Choice" list contains many interesting articles, but some of my personal favorites did not make the list. Today I present the "Editor's Choice" list of articles that deserve a second look. I've grouped
Recently Sanjay Matange blogged about how to color the bars of a histogram according to a gradient color ramp. Using the fact that bar charts and histograms look similar, he showed how to use PROC SGPLOT in SAS to plot a bar chart in which each bar is colored according
When creating a statistical graphic such as a line plot or a scatter plot, it is sometimes important to preserve the aspect ratio of the data. For example, if the ranges of the X and Y variables are equal, it can be useful to display the data in a square
Did you know that you can use the POLYGON statement in PROC SGPLOT to draw a map? The graph at the left shows the 48 contiguous states of the US, overlaid with markers that indicate the locations of major cities. The plot was created by using the POLYGON statement, which
