The overall wind values are easy to compare side by side. Note in the bar chart on the right, the bars are actually plotted using the High-Low plot, with Type=bar. Highlow x=theta low=low high=high / group=knots type=bar Styleattrs datacolors=(forestgreen lightgreen gold cxD00000) Title h=10pt 'Wind data as stacked HighLow segments' Click on the graph for a higher resolution image. We can certainly plot this data directly as a HighLow plot in the XY space as shown below. For simplicity, each group has equal number of percentages. This is done for ease of transformation later into the polar graph. I have generated Low and High values for each segment in the table on the right. These can be seen in the legend in the graph above. For 16 values around the circle, I generate the wind percentages by 4 "Knots" categories. I start with generating the data in (R, Theta) coordinates, as shown on the right. Here, we have used a "Bar" to represent the wind from each direction. Note, this visualization does not use a scatter plot, as was the case with the polar graph in the previous article. The data was generated using some trigonometric and random functions and does not represent real or sampled data. Here I have simulated wind data by direction and speed category. The Wind Rose graph on the right is created using the SGPLOT procedure. This graph was developed to depict the wind speed and direction, and can be useful to present any directional information, or information that is cyclical in nature. In this article, we will discuss another popular polar graph called the Wind Rose Graph. With SGPLOT, we can use either a Polygon plot or SGAnnotate to draw the circular grids. With GTL, we can use the Ellipseparm statement to display the circular grids. Setting Aspect=1 ensures the graph retains its shape, and we add the radial grid lines using Vector plot statement. Then, we can plot the graph using a scatter plot statement. When the measured data (R, Theta) are in the polar coordinates as radius and angle, then this data can be easily transformed into the XY space using the simple transform shown below. Last week I posted an article on displaying polar graph using SAS.
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