Geography · Lesson 18

Practical geography 3: drainage, settlement, communication, land use and sketch maps

JAMBWAECNECO

What the syllabus asks

JAMB: map reading and interpretation, physical and human features and their relationships on topographical maps.

WAEC: identification of cultural features (settlements, communication routes, city walls), description and explanation of drainage characteristics and pattern, patterns of communication, settlement and land use

NECO: identification of cultural features (settlements, communication routes, city walls), description and explanation of drainage characteristics and pattern, patterns of communication, settlement and land use

What you will learn

Describe the drainage of a map extract, including pattern and density.
Explain drainage patterns in terms of rock and relief.
Identify settlement types, patterns, sites and functions from map evidence.
Describe communication networks and relate them to relief and drainage.
Infer land use and economic activities from map evidence.
Explain relationships between physical and human features.
Draw an annotated sketch map at a reduced scale.
Answer a full 25-mark map question within 35 minutes.

Key points

Interpretation marks need evidence then reason.
Describe drainage: rivers, flow, tributaries, pattern, density, gradient.
Oke-Ofa drainage is dendritic with low density.
Nucleated, linear and dispersed patterns all occur on the extract.
Site factors: water, dry gentle land, route focus, defence.
Deduce functions only from symbols shown.
Roads follow gentle slopes and minimise bridges.
State inferences as probable.
Sketch maps: size, features asked for, key, title, north, scale.
Numbered points: one supported point per mark.

Start here: Concept summary: from measuring to interpreting

Units gp1 and gp2 dealt with the measurement tasks. The remaining marks in the map question reward interpretation: describing and explaining the drainage, settlement, communication and land use of the area and the relationships between them and the relief. The WAEC syllabus lists exactly these: “description and explanation of drainage characteristics and pattern; patterns of communication, settlement and land use”, and identification of “cultural features such as city walls, settlements, communication routes”.

Interpretation questions use command words that tell you what to write.

Identify / name: give the feature, with a grid reference if possible.
Describe: say what and where, with evidence (heights, grid references, distances). No reasons needed.
Explain / account for: give reasons, linked to map evidence.
Relationship / influence: show how one element (usually relief or drainage) affects another (settlement, roads, land use).

The golden rule is evidence then reason. A statement such as “Oke-Ofa is a nucleated settlement” earns a mark only if the map supports it; “Oke-Ofa is a nucleated settlement: about 14 buildings are clustered around the junction of the main and minor roads at GR 336614” earns the mark beyond doubt. Remember that the map shows only what exists. If the map does not show a mine, do not invent mining; if there are no symbols for crops, say that farming is likely and give the evidence (gentle slopes, rural settlements, footpaths), rather than stating it as fact.

All answers in this unit refer to the Oke-Ofa extract (gp1, Figure 2), reproduced below for convenience.

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Practice questions

1. Drainage density is total stream length divided by

area
number of rivers
height
rainfall

Show answer

A: area
km per km².

2. A tree-like drainage pattern is

radial
trellis
parallel
dendritic

Show answer

D: dendritic
Common on uniform rocks.

3. Rivers flowing outward from a central hill form a

centripetal pattern
trellis pattern
radial pattern
dendritic pattern

Show answer

C: radial pattern
Like spokes.

4. Rivers flowing into a central basin form a

trellis pattern
centripetal pattern
radial pattern
dendritic pattern

Show answer

B: centripetal pattern
Inward drainage.

5. A trellis pattern suggests

alternating hard and soft rocks
uniform rock
a volcano
a desert

Show answer

A: alternating hard and soft rocks
Tributaries join at right angles.

Key words

Drainage density: Total length of streams per unit area.
Dendritic: Tree-like drainage pattern on rocks of uniform resistance.
Trellis: Parallel streams with tributaries at right angles.
Confluence: Point where two rivers meet.
Watershed: High ground separating two drainage basins.
Nucleated settlement: Buildings clustered round a centre.
Linear settlement: Buildings strung out along a route.
Dispersed settlement: Isolated buildings scattered over the land.
Site: The land on which a settlement is built.
Route focus: A place where several routes meet.
Function: The main activities or services of a settlement.
Sketch map: A simplified map showing selected features.

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