The different types of diagrams can be divided into following heads - 

(1) One dimensional diagrams 

(2) Two dimensional diagrams 

(3) Three dimensional diagrams

(4) Pictograms 

(5) Cartograms 

(1) One Dimensional Diagrams or Bar Diagrams : 

Bar diagrams are the most common types of diagram. A bar is a thick line whose width is shown merely for attention. They are called one dimensional because it is only the length of the bar that matters and not the width. 

Kinds of Bar Diagrams : 

(i) Line Diagrams : When the number of items is large, but the proportion between the maximum and minimum is low, lines may be drawn to economise space. Only individual or time series are represented by these diagrams 

(ii) Simple Bar Diagrams : A simple bar diagram is used to represent only one variable. For example the figures of sales, production etc. of various years may be shown by means of simple bar diagram. The bars are of equal width only the length varies. These diagrams are appropriate in case of individual series, discrete series and time series. 

(iii) Multiple Bar Diagrams : In a multiple bar diagram, two or more sets of interrelated data are represented. Different shades, colors or dots are used to distinguish between the bars. These are used to compare two or more related variables based on time and place. 

(iv) Sub-divided Bar Diagrams : If a bar is divided into more than one parts, it will be called sub-divided bar diagram. Each component occupies a part of the bar proportional to its share in the total. For example total expenditure incurred by a family on various items such as food, clothing, education, house rent etc can be represented by means of sub-divided bar diagram. 

(v) Percentage Sub-Divided Bar Diagrams : Percentage subdivided bars are particularly useful to measure relative changes of data. When such diagrams are prepared, the length of the bar is kept equal to 100 and segments are cut in these bars to represent the components of an aggregate. 

(vi) Profit – Loss Diagrams : If relative change of cost & sales or profit or loss are to be represented with the help of bars, then profit – loss diagram are constructed. These diagrams are similar to percentage sub-divided bars and are prepared in the same way. 

(vii) Duo-Directional Bar Diagrams : In duo-directional bar diagram comparative study of two major parts of data is represented in a single bar. Such duo directional diagrams are represented on both sides of the horizontal axis, i.e. above and below the base line. 

(viii) Paired Bars : If two different informations which are in different units are to be presented then paired bar diagram are used. These bars are not vertical but horizontal and the first scale is in the first half and second scale is in the second half. 

(ix) Deviation Bar Diagram : Deviation bars are popularly used for representing net quantities i.e. net profit, net loss, net exports or net imports etc. Such bars can have both positive or negative values. Positive values are shown above the base line and negative values below it. 

(x) Progress Chart or Gant Chart : These charts are mainly used in factories for comparing the actual production with targeted production. By looking at it, it can be known how much production has been achieved and how much they are lacking behind the capacity. 

(xi) Pyramid Bar Diagram : These diagrams are constructed to show population distribution. The distribution of population according to sex, age, education etc are represented by this diagram. In this diagram, the base line is in the middle and its shape is like a pyramid. 

(xii) Sliding Bar Diagrams : These bars are like deo-directional bars but instead of absolute figures percentages of two variables are shown. One of them is shown on the right side of the base and the other on its left. 

(2) Two Dimensional Diagrams :

In two dimensional diagrams, the height as well as the width of the bars will be considered. The area of the bars represents the magnitude of data. Such diagrams are also known as area diagrams or surface diagrams. The important types are – 

(i) Rectangle diagram 

(ii) Square diagram 

(iii) Circle or Pie diagram 

(i) Rectangle Diagram : Rectangles are often used to represent the relative magnitude of two or more values. The area of rectangles is kept in proportion to the values. They are placed side by side like bars and uniform space is left between different rectangles. The rectangles may be of different types - a) Simple Rectangles 

b) Sub-divided Rectangles

c) Percentage sub-divided Rectangles 

(ii) Square Diagrams : When there is a large difference between the extreme values (example the smallest value is 4 and the biggest value is 800) is such a case square diagram is more appropriate. 

First of all square roots of the given values are calculated and the sides are taken in the proportion of square roots. The squares are drawn on the common base line, serially either in increasing or decreasing heights to have beautiful and attractive appearance. 

For calculating the scale, the area is calculated by squaring its side, on the basis of that value of 1 sq.cm. is calculated. 

(iii) Circle or Pie Diagram : These diagrams are more attractive, therefore, pie diagrams are preferred to square diagrams. These diagrams are used to represent data of population, foreign trade, production etc. 

The square roots of the given values are calculated and then it is divided by some common factor so as to attain the radii for the circles. The area of the circle is calculated by the formula - (π r²) . The sides for squares are taken as the radii for different circles. 

A circle can also be sub-divided on the basis of angles to be calculated for each component. There is 360 degree at the centre of the circle and proportionate sectors are cut taking the whole data equal to 360 degrees. Such a circle is known as sub-divided circle or Angular diagram. 

(3) Three Dimensional Diagrams : 

In three-dimensional diagrams length, width and height (depth) are taken into consideration. If the difference between the minimum and maximum value is so wide as it is difficult to represent them by square or circle diagram, then three dimensional diagram is used. For this cubic roots of the given numbers is calculated. Three dimensional diagrams include cubes, blocks, spheres and cylinders etc. 

(i) Pictorgrams : Pictograms are used by government and nongovernment organizations for the purpose of advertisement and publicity through appropriate pictures. It is a popular technique particularly when statistical facts are to be presented for a layman having no background of mathematics or statistics. For representing data relating to social, business and economic phenomena for general masses in fairs and exhibitions, this method is used. 

(ii) Cartograms : Cartograms or statistical maps are also used to represent data. Cartograms are simple and elementary form of visual presentation and are very easy to understand. While highlighting the regional or geographical comparisons, mapographs or cartograms are generally used.