The Basis of Map Interpretation

Hello Steemians!!

Recently I started my new series on what I learnt in Class. For some days now I've been busy, that's why I couldn't update the series.

In my last series I talked about deformation of rocks. Today I will be talking about map interpretation, types of map, importance of map, basic elements of a map and how to represent data on a map.

Before we get into detailed discussion about map, let's check out what a map is;

What is a Map

A map is a scaled 2-dimensional representation of three dimensional features. It is a means of conveying variety of information about features in a locality on a piece of paper which could be either man made or natural.

We can also take a map as a picture or representation of the Earth's surface, showing how things are related to each other by distance, direction, and size. Maps are a way of showing many things about a portion of the earth's surface on a flat piece of paper that can be carried and transported easily. A map is not a photograph of the Earth's surface. It can show many things that a picture cannot show, and as a result, a map looks different in many ways from a photograph of the Earth's surface. Source

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Types of Map

• Political Map :- It potrays political boundaries. Examples of political maps are maps of various countries. Map of Nigeria or Map of Canada.

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• Thematic Map :- They convey information of given and defined phenomena. E. g Climatic map, drainage map and vegetation map.

• Topographical Map :- They are elevation maps that shows the relationship between different areas in terms of their elevation from a reference datum. The most common datum is mean sea level.

• Geologic Map:- It shows distribution of lithologic units in a selected area.

• Base Map:- Can serve as a reference map or starting map which can either be a topographical map, thematic map or an old geological map that could be modified to generate a new map.

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Importance of Map

• A map can help us locate our position e.g Sailor.
• It can help convey information at a glance.
• A properly interpreted map can be used for exploration purpose.
• A proper scaled map can be used to convey large information or data on a small piece of paper.

Basic of Element of a Map

• Title of a map should be well represented at the top of a map.

• Scale:- A scale is a relational components of a map that enables us conveniently represent a large dimensional area on the ground on a small piece of paper.

Your choice of scale is dependent on;

1. The amount or number of features shown on the map.
2. The volume of details you want to represent.

Types of Scales

• Statement Scale (1cm rep. 1000m)
• Linear Scale
• Fraction Scale (1:50,000)

A small scale map will show small details or map but can represent a large number of features while a large scale map will show smaller number of features with large details.

• Map Boundary :- The boundary of the map must be defined.

• Legend/Key:- Is a means to describe the various features represented on a map.

• Direction:- It tends to give us an idea of the positon of your north, south, east and west of the area covered by that map. The position of N, S, W, and E direction on the ground can be determined by the use of a compass or traditionally by the position of the sun.

• Co-ordinates:- They are readable value that can help us identify our exact location on a map. Co-ordinates can come in several oaur either as latitude and longitude, easting and northing, x and y Co-ordinates.

Representation of Data on a Map

There are three techniques used in representing data gotten from the field on a map.

1. Use of contour lines
2. Use of benchmark or spot height.
3. Use of trignometrical station.

• Contour Lines:- Majority of maps use the contour lines as the vehicle to convey the various type of data. By definition, a contour line is a line that connects points of equal values. Any map that use contour lines to convey information is called a CONTOUR MAP.

• Benchmark:- There are any item used to mark a point such as elevation reference. They are usually carved sets on stones,rock or concrete. If an elevation is mapped on a map but without any physical mark on the ground it is therefore a spot height.

• Spot Height:- They are exact spot on a map with a value recorded beside it that represents a value above a given datum.

Reference

• Ref 1

• Ref 2

• Ref 3

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