<Li> A data chart is a type of diagram or graph, that organizes and represents a set of numerical or qualitative data . </Li> <Li> Maps that are adorned with extra information (map surround) for a specific purpose are often known as charts, such as a nautical chart or aeronautical chart, typically spread over several map sheets . </Li> <Li> Other domain specific constructs are sometimes called charts, such as the chord chart in music notation or a record chart for album popularity . </Li> <P> Charts are often used to ease understanding of large quantities of data and the relationships between parts of the data . Charts can usually be read more quickly than the raw data . They are used in a wide variety of fields, and can be created by hand (often on graph paper) or by computer using a charting application . Certain types of charts are more useful for presenting a given data set than others . For example, data that presents percentages in different groups (such as "satisfied, not satisfied, unsure") are often displayed in a pie chart, but may be more easily understood when presented in a horizontal bar chart . On the other hand, data that represents numbers that change over a period of time (such as "annual revenue from 1990 to 2000") might be best shown as a line chart . </P>

What are three important features of charts and graphs