Distance for circular histograms

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However, in order to properly account for the periodicity of circular data, a custom definition of distance may need to be developed. This could involve transforming the data into a circular scale or using circular statistical techniques.
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mnb96
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Hello,
I know that several definitions of distances between pdf's were definied, for example: Bhattacharyya distance.
I would like to know if there exist some definitions of distance between "circular" histograms.

A practical example would emerge when considering histograms deriving from sets of samples of wind-direction angle of the kind [tex]\Theta_n = \{ \theta(1),\ldots, \theta(n) \}[/tex].

A "good" definition should properly take into account the periodicity, hence to classify the following two histograms as very close to each other:

[tex]H_{1}(\theta)=\begin{cases}
1 & \theta=0^{\circ}\\
0 & otherwise\end{cases}[/tex] [tex]H_{2}(\theta)=\begin{cases}
1 & \theta=359^{\circ}\\
0 & otherwise\end{cases}[/tex]
 
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Yes, there are several definitions of distance between circular histograms. One such definition is the Jensen-Shannon divergence, which is a symmetric and bounded measure of the similarity between two probability distributions. Other options include Kullback-Leibler divergence, Bhattacharyya distance, and Hellinger distance. All of these measures can be applied to circular histograms.
 

FAQ: Distance for circular histograms

What is the purpose of a circular histogram?

A circular histogram is a graphical representation of data that displays the distribution of values around a circle instead of a traditional bar or line graph. It is often used to visualize data that is cyclical or periodic in nature, such as time series data or directional data.

How is distance calculated for circular histograms?

The distance for circular histograms is typically calculated using circular statistics, which takes into account the periodic nature of the data. This involves converting the circular data into polar coordinates and calculating the mean vector length or circular variance. Other measures such as angular deviation or circular standard deviation can also be used to measure distance.

Can circular histograms be used for non-circular data?

While circular histograms are primarily used for visualizing cyclical data, they can also be used for non-circular data. However, in these cases, the circular aspect of the graph may not be as informative and other types of graphs may be more suitable.

How do circular histograms differ from traditional histograms?

In traditional histograms, the data is organized into categories or bins and the frequency of each category is represented by the height of a bar. In circular histograms, the data is organized around a circle and the frequency is represented by the distance from the center of the circle, with longer distances indicating higher frequencies. Additionally, traditional histograms typically display data on a linear scale, while circular histograms use a circular scale.

What are the advantages of using circular histograms over other types of graphs?

Circular histograms allow for a more intuitive visualization of cyclical data and can reveal patterns or trends that may not be apparent in traditional graphs. They also allow for easier comparison of data across different time periods or directions. Additionally, circular histograms can be used to display large datasets without becoming cluttered or difficult to interpret.

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