5.1.6 . One-dimensional or Bar diagrams
Bar diagrams are the most common type of diagrams used in practice. 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. When the number of items is large, lines may be drawn instead of bars to economise space. The special merits of bar diagrams are the following :
(i) They are readily understood even by those unaccustomed to reading charts or those who are not chart-minded.
(ii) They posses the outstanding advantage that they are the simplest and the easiest to make.
(iii) When a large number of items are to be compared they are the only form that can be used effectively.
While constructing bar diagrams the following points should be kept in mind.
(i) The width of the bars should be uniform throughout the diagram.
(ii) The gap between one bar and another should be uniform throughout.
(iii) Bars may be either horizontal or vertical. The vertical bars should be preferred. Figures at the end of each bar so that the reader can know the precise value without looking at the scale. This is particularly so where the scale is too narrow, for example, 1” on paper may represent 10 crore people.
Types of Bar Diagrams :
Bar diagrams are of the following type :
(a) Simple bar diagrams
(b) Sub-divided bar diagrams
(c) Multiple bar diagrams
(d) Percentage bar diagrams
(e) Deviation bars