Free Photogrammetry Document - Symbols in Map and classification of symbols

We are continuing our free article publishing in photography development to help photogrammetry students, GIS students, remote sensing students and all professionals related to this industry. This is a free photogrammetry document. More free photogrammetry study materials are available in Photogrammetry FAQ page.We will discuss various Mapping symbols and classification of mapping symbols in this post.

What is symbol? Write classification of symbol?

A symbol is any drawn or otherwise constructed image used as a means of presentation of data. Symbols can be classified mainly into 3 types.

a. Point Symbol: These are used to indicate location and entity or other characteristic of a feature of small territorial extent to map scale. The aspect of scale is very important at a scale of 1:1 million a city might be indicated by a point but it would never be case at a scale of 1:10,000.

b. Line control: These symbols are used to represent features of linear characteristic like roads, railways etc.

c. Area Symbols: These are used to represent features of a considerable area extent.

Quantitative and Qualitative Symbol

This is second major division of symbols

Qualitative Symbol: These are symbols, which deal with quality i.e., by these symbols identity of features is indicated or nature of feature is described.

Quantitative Symbol: These are symbols, which deal with quantity or amount of features. Both qualitative and quantitative types of symbols can take form of a point, line and area.

Qualitative Point Symbols

They can be further divided into following categories

(i) Descriptive/ pictorial type: These symbols are actual pictorial representation of features. They extent to show temple, different types of trees.
(ii) Geometric/purely abstract type: Symbols are simply geometric. Shapes are chosen at random to represent features. They bear no resemblance to features. For example hut, spring and well.
(iii) Letter or number symbols: Abbreviations are often used to give identity of a specific features along with symbols
i.e., P.O for Post Office
P.S for Police Station
R.H for Rest House.
(iv) Letter or Number Codes: Letter is very often used on soil maps or geological maps to clarify complex area symbols or to give additional information.

Qualitative Line Symbols
There are 2 types of qualitative line symbols

a. Descriptive type: These indicate natural or man-made features, which exists in terrain. In many cases, line symbols on large-scale maps indicate features at a true size.
b. Abstract or imaginary line symbol: They represent features that don’t exist on ground or line features, which are imaginary. Examples are
i. Meridians
ii. Parallels
iii. Grid Lines
iv. Contours

Qualitative Area Symbol

a. Descriptive type : Here they show the distribution of different kind of phenomenon.

b. Abstract type: They show different political units using patterns of soils using color or pattern.