Representation of any numerical data by using diagrams is known as diagrammatic representation. Diagrammatic data representations give a simple and easy understanding of any numerical data collected as compared with the tabular form of the data or textual form of the data.

1. DIAGRAMMATIC
REPRESENTATION
A.JEEVARATHINAM
ASSISTANT PROFESSOR
V.V.VANNIAPERUMAL COLLEGE FOR WOMEN
VIRUDHUNAGAR

2. INTRODUCTION
• A diagram is a visual form for presenting statistical data for
highlighting the basic facts and relationship which are
inherent in the data.
• It attracts the attention and it is a quicker way of grasping the
results saving the time.
• They are more attractive and easier
to understand.
• Diagrams are an essential operational tool for the
presentation of statistical data.
• They are objects, mainly geometrical figures such as lines,
circles, bars, etc.

3. DIAGRAMMATIC REPRESENTATION
MEANING
• Representation of any numerical data by using diagrams is
known as diagrammatic representation.
• Diagrammatic data representations give a simple and easy
understanding of any numerical data collected as compared
with the tabular form of the data or textual form of the data.
• The diagrammatic representation of data is a method used in
the analysis and exploration of information with the help of
diagrams.
• This also includes the use of color, layout, and shape to
encode data.
• The aim is to make complex information more accessible and
easy to understand for everyone.

4. RULES FOR MAING A DIAGRAM
 A diagram should be neatly drawn and attractive.
The measurements of geometrical figures used in diagram
should be accurate and proportional.
 The size of the diagrams should match the size of the paper.
 Every diagram must have a suitable but short heading.
 The scale should be mentioned in the diagram.
Diagrams should be neatly as well as accurately drawn with
the help of Drawing instruments.
Index must be given for identification so that the reader can
easily make out the meaning of the diagram.
 Footnote must be given at the bottom of the diagram.
Economy in cost and energy should be exercised in drawing
diagram

5. TYPES OF DIAGRAM
i. One Dimensional Diagrams or Bar Diagrams
ii. Two Dimensional Diagrams
iii. Pie Diagrams
iv. Pictogram
v. Cartogram

6. ONE DIMENSIONAL DIAGRAMS
• One- dimensional diagram means a diagram which has only
one dimension or it is representing its qualitative or
quantitative property in only one dimension.
• Only the length of the lines or bars matters and not the
width.
• They are simplest and easiest one.
• The following are the main types
 Line diagram
 Simple bar diagram
 Multiple bar diagram
 Subdivided bar diagram
 Percentage subdivided bar diagram

7. LINE DIAGRAM
• Use the line that connects the points or portions of the
various data in the graph by taking two variables on horizontal
and vertical axes.
• The data's are plotted as points.
• The points are joined by the lines.
• There is an equal gap between different lines.

8. SIMPLE BAR DIAGRAM
• In the bar diagrammatic representation of data, the data can
be represented by rectangular bars.
• The height of the bars gives the value or frequency of the
variable.
• All rectangular bars should have equal width.
• This is one of the best-used tools for the comparison of the
data.

9. MULTIPLE BAR DIAGRAM
• These diagrams are used for representing two or more sets of
inter-related data.
• This is helpful in making the comparison of the values relating
to different variables in a set and a comparison of the values
of the same variable over of given period of time.

10. SUBDIVIDED BAR DIAGRAM
• A sub-divided bar diagram is used to present data having 2 or
more components.
• Simple bar diagram is first drawn with the length of the bars
proportional to the totals of the component parts and then it
is sub divided into parts of length proportional to the
component magnitudes and each part given a different color
or shading.

11. PERCENTAGE SUBDIVIDED BAR
DIAGRAM
• In this the component parts are expressed as the percentages
of the total and a component bar diagram is drawn with all
bars having equal length.

12. DIFFERENCE BETWEEN SUBDIVIDED BAR DIAGRAM
AND PERCENTAGE SUBDIVIDED BAR DIAGRAM

13. TWO DIMENSIONAL DIAGRAMS
• In geometry, a two-dimensional shape can be defined as a
flat plane figure or a shape that has two dimensions – length
and width.
• Two-dimensional or 2-D shapes do not have any thickness
and can be measured in only two faces.
• In two-dimensional diagrams the length as well as the width
of the bars is considered.
• Thus the area of the bars represents the given two-way
classified data.
• Two dimensional diagrams are also known as surface
diagrams or area diagrams.
• So, two dimensional diagrams are also known as “Area
Diagrams.”
The following are the types of two dimensional diagrams:
(i) Rectangles
(ii) Squares
(iii) Circles

14. TWO DIMENSIONAL DIAGRAMS -
Rectangles
• This form is quite popular.
• In rectangles diagram given numerical figures
are represented by areas of the
rectangles.
• So, rectangles diagram is drawn by taking one
of the two variables as lengths and
another variable as breadths of the rectangles
along two axes.

15. TWO DIMENSIONAL DIAGRAMS -
Rectangles

16. TWO DIMENSIONAL DIAGRAMS -
Squares
• The method of drawing
a square diagram is
very simple.
• One has to take the
square-root of the
values of various items
that are to be shown in
the diagrams and then
select a suitable scale
to draw the squares.
• Cannot use a
rectangular diagram
when the values of the
items greatly vary. the
data are represented in
squares with equal
length and width.

17. TWO DIMENSIONAL DIAGRAMS -
Circles
Circles can be used in all those cases in which squares are used.
Circles are difficult to compare and as such are not very popular in
statistical work. When it is necessary to use circles, they should be
compared on an area basis rather than on a diameter basis, as the
diameter basis is very misleading. Compared to rectangles, circles
are more difficult to construct and interpret.

18. PIE DIAGRAMS
• The Pie diagram is a circular
diagram. A circle which has
360° is divided into different
sectors.
• Angles of the sectors,
subtending at the center, are
proportional to the magnitudes
of the frequency of the
components.
• When a circle is sub-divided
into various component sectors,
it is called a Pie diagram.
• The pie diagram shows the
relative changes in data and
represents each component in
a percentage manner.

19. PICTOGRAM
• Pictograms are very popularly used in presenting statistical
data.
• They are not abstract presentations such as lines or bars but
really depict the kind of data we are dealing with.
• Representation of numerical figures using pictures, then the
diagram is called pictogram.
• They look really attractive but they are difficult to create.

20. CARTOGRAM
• The alternative term for a
cartogram is a map
diagram.
• By using a map diagram
we can represent data
related to a country or
geographical area.
• They are meant to
represent types of
characteristics such as
Density of population,
Crop yield and Amount of
rainfall.