A diagram is a two-dimensional geometric symbolic representation of information according to some visualization technique. Sometimes, the technique uses a three-dimensional visualization which is then projected onto the two-dimensional surface. The word graph is sometimes used as a synonym for diagram.A diagram is a 2D geometric symbolic representation of information according to some visualization technique. Sometimes, the technique uses a 3D visualization which is then projected onto the 2D surface. The term diagram in common sense can have two meanings. visual information device: Like the term "illustration" the diagram is used as a collective term standing for the whole class of technical genres, including graphs, technical drawings and tables.[1] specific kind of visual display: This is only the genre, that show qualitative data with shapes that are connected by lines, arrows, or other visual links.

Cycle diagram,

In general an activity diagram shows a sequence of activities.

A chart is a graphic depicting the relationship between two or more variables with a discrete or continuous value range, used, for instance, in visualising scientific data. Charts are often used to make it easier to understand large quantities of data and the relationship between different parts of the data.

A flow chart is a schematic representation of an algorithm or a process, or the step-by-step solution of a problem.Flow charts use suitably annotated geometric figures connected by flow lines for the purpose of designing or documenting a process or program.

A pie chart (or a circle graph) is a circular chart divided into sectors, illustrating proportion. In a pie chart, the arc length of each sector (and consequently its central angle and area), is proportional to the quantity it represents. When angles are measured with 1 turn as unit then a number of percent is identified with the same number of centiturns. Together, the sectors create a full disk. It is named for its resemblance to a pie which has been sliced. The earliest known pie chart is generally credited to William Playfair's Statistical Breviary of 1801.[1][2]The pie chart is perhaps the most ubiquitous statistical chart in the business world and the mass media.[3] However, it has been criticized,[4] and some recommend avoiding it,[5][6][7][8] pointing out in particular that it is difficult to compare different sections of a given pie chart, or to compare data across different pie charts. Pie charts can be an effective way of displaying information in some cases, in particular if the intent is to compare the size of a slice with the whole pie, rather than comparing the slices among them.[1] Pie charts work particularly well when the slices represent 25 to 50% of the data,[9] but in general, other plots such as the bar chart or the dot plot, or non-graphical methods such as tables, may be more adapted for representing certain information. It also shows the frequency within certain groups of information.

A bar chart or bar graph is a chart with rectangular bars with lengths proportional to the values that they represent. The bars can be plotted vertically or horizontally.Bar charts are used for plotting discrete (or 'discontinuous') data which has discrete values. Some examples of discontinuous data include 'shoe size' or 'eye color', for which you would use a bar chart. In contrast, some examples of continuous data would be 'height' or 'weight'. A bar chart is very useful if you are trying to record certain information whether it is continuous or not continuous data. Bar charts also look a lot like a histogram.They are often mistaken for each other.