Grid System MCQs Quiz | Class 9
This quiz is for Class 9 students studying NCC (Code 076), focusing on Army Unit 3: Map Reading. It covers key topics like understanding grid references and performing basic grid reading. Test your knowledge, submit your answers to see the results, and download your personalized answer sheet as a PDF.
Understanding the Map Grid System
The grid system is a network of evenly spaced horizontal and vertical lines drawn on a map, used to pinpoint locations with precision. For NCC cadets, mastering grid references is a fundamental skill in map reading, essential for navigation, reporting locations, and coordinating movements during training and operations.
Key Concepts: Eastings and Northings
The grid on a map is made up of two sets of lines:
- Eastings: These are the vertical lines that run from the top to the bottom of the map. Their value increases as you move from west to east (left to right).
- Northings: These are the horizontal lines that run from left to right across the map. Their value increases as you move from south to north (bottom to top).
A simple way to remember how to read them is the cardinal rule of map reading: “Along the corridor, then up the stairs.” This means you always read the Easting value first, then the Northing value.
Reading Grid References
Grid references come in different levels of precision, most commonly 4-figure and 6-figure.
1. Four-Figure Grid Reference
A 4-figure grid reference identifies a specific 1km by 1km grid square on the map. It is used to locate a general area or a large feature.
- Step 1: Find the Easting line number immediately to the left of the desired square. This gives you the first two digits.
- Step 2: Find the Northing line number immediately below the desired square. This gives you the last two digits.
- Example: A reference of ‘2345’ means the square is to the east of Easting line 23 and to the north of Northing line 45.
2. Six-Figure Grid Reference
A 6-figure grid reference is more precise and locates a point within a 100m by 100m area inside a grid square. This is used for locating smaller features like a bridge, building, or specific landmark.
- Step 1: First, find the 4-figure reference for the square (e.g., 2345).
- Step 2: Imagine the grid square is divided into 10 smaller columns (for Eastings) and 10 smaller rows (for Northings).
- Step 3: Estimate how many tenths you need to move east (right) from the Easting line to reach your point. This digit becomes the third number of your reference.
- Step 4: Estimate how many tenths you need to move north (up) from the Northing line to reach your point. This digit becomes the sixth number of your reference.
- Example: A reference of ‘235458’ means: Easting 23, then 5 tenths across. Northing 45, then 8 tenths up.
| Reference Type | Example | Precision | Use Case |
|---|---|---|---|
| 4-Figure | GR 1485 | 1 km square | Locating a village or a forest area. |
| 6-Figure | GR 143857 | 100 m square | Pinpointing a specific building, bridge, or temple. |
Quick Revision Points
- Grid lines are numbered lines on a map that form squares.
- Vertical lines are Eastings; their value increases to the East.
- Horizontal lines are Northings; their value increases to the North.
- The golden rule is: Read Right, Then Up.
- A 4-figure reference (e.g., 3152) identifies a 1km grid square.
- A 6-figure reference (e.g., 315528) identifies a 100m x 100m point within a grid square, offering greater accuracy.
Extra Practice Questions
- If you are given a 6-figure grid reference ‘782345’, what do the numbers ’78’ and ’34’ represent?
- Explain the mnemonic “Along the corridor, then up the stairs” in the context of reading a grid reference.
- Which type of grid reference would be more suitable for directing a patrol to a specific well in a village, and why?
- On a standard 1:50,000 scale map, what is the real-world distance represented by one grid square?
- If a point is located exactly in the center of the grid square 4567, what would its 6-figure grid reference be?
