A histogram widget is a type of bar chart that graphically displays the values of numeric attributes to show distribution. A good data source for a histogram widget has attribute values that are continuous in nature and can be divided into equal intervals.
A histogram is defined for a single attribute field, such as population. When configuring the histogram, you can set the number of equal intervals used to classify the data. You can also use a histogram to display categorical data, such as types of crime for a given police district. In this case the data is nominal; there is no relationship or order between each of the categories.
In an emergency management scenario following an earthquake, you could graph the value of structural damage occurring to buildings. This example histogram shows numeric values grouped into five intervals.