Overview of Data – Its Source and Compilation

Estimated time: 12 minutes

CBSE: Class 12

Key Points: Data and Its Importance in Geography

Data are numerical facts or measurements collected from the real world. A single measurement is called a datum.
Raw data alone may not give clear meaning; it must be analysed and organised to derive useful information.
Data is important in geography to study patterns like population, rainfall, crop production, migration and city growth.
Proper statistical analysis and presentation of data is necessary to avoid wrong conclusions (statistical fallacy).
Modern geographical studies focus more on quantitative analysis using data to explain relationships between different variables clearly and logically.

CBSE: Class 12

Data is collected from two sources: Primary sources and Secondary sources.
Primary data is collected first-hand by a person or organisation for the first time, while secondary data is taken from already published or unpublished records.
One important source of primary data is personal observation, where information is collected directly through field surveys.
Interviews are used to collect direct information through conversation, and questions should be simple, polite and unbiased.
Questionnaires and schedules help collect data from large areas; in questionnaires respondents fill answers themselves, while in schedules an enumerator fills it, making it useful even for illiterate people.

CBSE: Class 12

Secondary data is data already collected by others and available in published or unpublished records.
Government publications are the main sources, e.g. Census of India, NSS reports, IMD weather reports, statistical abstracts, commission reports.
Semi-government and international sources include reports from Municipal Corporations, Urban Development Authorities, and UN agencies like UNESCO, UNDP, WHO, FAO (e.g. Human Development Report).
Private sources include yearbooks, surveys, research reports published by private organisations, along with newspapers and magazines.
Unpublished sources include village revenue records (patwari), municipal plans, government documents, and records of companies, trade unions, political organisations, and welfare associations.

CBSE: Class 12

Raw data is unorganised information. To make it meaningful, it must be classified and tabulated.
A statistical table arranges data in rows and columns, making it easy to understand, compare and save space.
Data can be presented in three forms:
Absolute values (original numbers), Percentages/Ratios, and Index numbers.
Index number shows change over time or place.
Base year is usually taken as 100 and other years are compared with it.
Grouping of data means dividing raw data into classes (like 0–10, 10–20, etc.) to reduce volume and simplify study.
Classification is done using tally marks (Four and Cross method), and the final result is shown as a frequency distribution table.
Frequencies are of two types:
Simple frequency (f) = number of observations in a class,
Cumulative frequency (Cf) = total frequency up to that class (helps in “less than” or “more than” comparisons).