geog 204 lecture 3 map int 2014

8/12/2019 GEOG 204 Lecture 3 Map Int 2014

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Department of Geography &

Resource Development

LECTURE 3

Principles of Map Interpretation

Interpreting physical or natural features

Interpreting cultural or human features

Centre for Distance Education, University of Ghana, egon


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D! GE"G! #$% M'P I()ERPRE)')I"( '(D *UR+E #$-.

/ac0ground Interpretation of maps

There is the need to first identify identical sections on the map. This must be done

based on common characteristics portrayed within the selected area. Demarcation

is therefore necessary as an initial step in map interpretation. Demarcation of the

map into homogeneous units or regions is done by grouping identifiable features into

broad categories, natural and human, as shown, for example, in Table 1.1.

Accordingly, we can categori1enatural features into broad groups comprising relief

or topography, drainage and vegetation. Human, cultural or manmade features, on

the other hand, comprise settlements and population, transportation and

communication networ!s, and other land uses.

Table 1.1 "ist of common natural and human features on a map

(atural or Physical 2eatures Cultural or 3uman 2eatures

Relief 2eatures

#pur

$idges

%lateau

%lain

#carp , etc

*ettlement and Population 2eatures

#ite

%attern

&orms

#ituation

&unction

Drainage 2eatures

1. Age or stage of rivers

'. Drainage patterns

Dendritic

Trellis

%arallel

$adial

Communication 2eatures

$ails

$oads

Air routes

+egetation 2eatures

$ainforest

#avannah

Desert

and use 2eatures

(conomic Activities

#ource) Authors

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GE"G! #$% M'P I()ERPRE)')I"( '(D *UR+E #$-.

As you can see from the Table above, the list of features that may be represented

on a map will vary according to what pertains to the specific area that is mapped.

*aps are therefore demarcated into units or regions based on the natural and+or

cultural features that are found on the map. They are further described and

examined based on their individual, general and prominent characteristics. The

characteristics or features are grouped into natural and cultural or human features.

In map interpretation, you should be able to express your opinion on what you see

on the topographical sheet. ou must also explain every possible feature. our

ability to do this will depend on how to identify and demarcate the map into similar or

homogeneous areas.

'ctivity -!- ou are provided a set of maps

-omment on the main features found on a map. n what basis would you group

them to facilitate map interpretation4

*ummaryI have discussed with you two broad categories of features which are important as a

first step to map interpretation. I have also explained to you what constitute physical

and cultural features. It is upon these features that one can divide the map into

common units.

*ection # Interpreting (atural or Physical 2eatures

Introduction

-ontours are very important in showing landforms on the map. -ontours on a

topographical sheet show the uneven nature of the terrain or the environment. They

attempt to represent physical reality of the landform or topography on the land. &rom

contours, you can identify the various forms and features of relief or topography,

drainage and possible vegetation associated with them.

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Relief

The relief or topography of an area as you are already aware means the position

and character of landforms, e.g. highlands and lowlands /Hilton, 102. The most

important single means of showing relief is by contours. Thus, contours are used to

show the si3e, shape and slopes of relief features such as plateaux, hills, ridges and

scarps among other. There are other methods of showing relief such as layer tinting

or colouring, hill shading and hachuring. The specific variations in contour shape,

spacing and alignment indicate the specific relief feature being portrayed. Thus, to

demarcate a map into relief regions, the map has to be carefully studied to identify

the character of the landscape changes from lowland to highland. Accordingly, the

process of demarcation will entail a series of steps of grouping the ma4or or primary

division, subdivisions and subsubdivisions.

'ctivity #!-

(xplain briefly the term 5relief6. 7ame the common methods for representing relief.

Description of some common relief features

/i2. *pur) They are shown by 8shaped contours with the apex of the contour

pointing away from the highland and the smallest contour being the highest

point of the spur and height decrease outwards.

/ii2. Ridge) This is an elongated hill. It is indicated by closely spaced contours

with slopes running down from both sides and the length is many times

greater than the width.

/iii2. *carp or Escarpment) It is a highland with a gentle slope at one side and a

steep slope on the other side. The difference is that contour spacing for the

5dip slope6 or gentle side is wider than the steep slope called the 5scarp slope6.

/iv2. Plateau) A highland with a relatively broad top. This is shown on a map by a

number of closely spaced contours showing the steep rising of the land and a

comparative absence of contours towards the centre.

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There are many other uni9ue features which are associated with particular

landscapes around us. ou will come across them in your reading and travel.

Procedures for demarcating and descri5ing relief

ou may be as!ed to divide all or parts of a map into two or more relief regions. In

addition, you may be as!ed to write an account of all or some of these. To identify

relief regions, you must first study the map carefully. Then you must see where on

the map the character of the landscape changes : from lowland to highland, for

example, or from an area with many streams to one with very few. #ometimes one

or more of the main divisions will need to be subdivided. &or example, a lowland

region may consist partly of a broad rivervalley floor, and partly of a coastal or otherplain. #ome maps are so simple, that is, easy to recognise the divisions at a glance;

other maps need more careful study.

The following are some general procedures for demarcating and describing relief)

/i2. Ta!e note of the scale of the map, the convectional signs for relief which are

shown in the legend+!ey and whether heights are in metres or feet.

/ii2. %roceed to loo! at the general appearance of the land shown on the map. Are

there ma4or contrasts in relief between one part of the map and another. ?., 100

'ge or stage of river 5asin features

Drainage basin may also be divided into youthful or young, mature and old stages.

The course of rivers in the above stages must be identified and described. The

respective cross sections are shown in &igure 1.' below)

&igure 1.' A $iver %rofile showing the shape of the valley in each stage

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#ource) The web

Guidelines for demarcating and descri5ing drainage features

/i2. 7ote the scale of the map, the conventional signs for drainage which are

shown in the !ey, and whether the heights are in metres or feet.

/ii2. &ind the main rivers and their tributaries, and their direction of flow. Do the

rivers have a pattern li!e the ones described earlierovernment policies

*ettlement Patterns

This is the general shape of the settlement. #ome factors influence the form that

settlements ta!e. #ettlement patterns could be linear, dispersed, nucleated or may

ta!e no particular pattern depending on the factors that affect the site of the

settlement. A combination of these patterns may also occur

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inearThis may be a result of a constrictive site example the alignment of a

routeway or river or an elongated relief feature such as a ridge or escarpment

base. #ometimes the reason is cultural, for example the traditional village

layout in A!uapem, ?wahu, the Hu3a system in ?robo and the coastal

settlement pattern along ?eta and Anloga. (ucleated, Concentric or circularIn this case, growth has generally been

outwards from a central core or nucleus.

DispersedTypical pattern here is the compound system associated with the

compound system of farming in parts of 7orthern >hana.

Rectangular or grid=ironThis is a system where town develops in bloc!s.

2unctions of settlements

The pattern of land use within the form of larger settlements may reveal welldefined

functional 3ones i.e. 3ones within which there are concentration of particular activity.

#ettlement may perform the following functions or a combination of functions.

Administrative

-entral usiness District

$ecreation

-ultural

(ducational

$esidential Industrial

-ultivation+farms

Communication

There are many !inds of communication networ!s. The main ones found on maps

are roads, railways, airfields, navigable waterways, telegraph and telephone lines.

These are represented by conventional symbols on maps explained in the !ey or

legend. >eneral coverage of map by communication lines should be noted.

Road:These are usually classed into 1stclass, 'ndclass and Brdclass and

sometimes Cthclass roads and motorable dryweather roads and local loads.

ther route ways such as footpaths are also shown on maps.

Rail7ay) These may indicate some economic activity and may influence

settlement patterns. $ail lines avoid steep slopes and sharp curves and use

level land as much as possible

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'ir7ays, >ater7ays, etc

"ther land uses

ther land use types may include those related to economic activity e.g. agriculture

/crops and livestoc!2, forests, 9uarries, fishing, mining and milling. (vidence for such

land use activities on maps can be direct or indirect. Direct evidence is provided on

maps by text and by special symbols and indirect is provided in various ways and

relies on deduction.

Guidelines for interpreting human features

Describing a human feature in isolation is very difficult thing to achieve. To do this

successfully it is common to)

Describe them on the map sheet relating them to the physical features on the

map.

#ome of the cultural features such as communication and settlement

features are easier to notice than the land use features.

=hen recounting these features, the legend provided should be of immense

assistance. ou must loo! out for guidingcluesE which will help you ma!e

correct guesses.

'ctivity .!-

=hat is a legend for a map< f what significance is the legend for interpreting

human features on a map. ?. /1002 Comprehensive Mapwork for West African Schools,

Heinemann, #cotland.

7ima!o, D.A. /10'2 Map Reading for West Africa, "ongman >roup "td, @.?.

%ritchard, . *. /10C2 Practical Geography for Africa, "ongman >roup "td, @.?.

geog 204 lecture 3 map int 2014

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