SOCIAL SCIENCES
, CONTOUR LINES [MAPWORK]
CONTOUR LINES → (contour) lines on a map > connect places of the same height above sea
level [indicate landscape phenomena]
→ symbolic horizontal line indicating height and the shape of the slopesi
→ accurate way to indicate relief on maps [shape, size & steepness]
[relief > shape of the earth's surface > unevenness of the surface]
NOTES:
Z Numbers / figures on the
contour lines > HEIGHT (in
Steep slope Gradual slope meters above sea level)
Z Contour interval > distance
between each contour line
(e.g. 20m)
DIFFERENCE BETWEEN A HILL
AND A RIDGE:
Height (m) ridge > long, narrow & steep
hilltop / mountain range
HILL
RIDGE
STEEP & GRADUAL SLOPES:
[Slope = Gradient]
Gradient > describes how style is a slope [determined by the angle of the slope]
GRADE 9 > TERM 1
STEEP GRADIENT IN SLOPE → if there is a large difference in height between locations,
while the horizontal distance between the two locations is small (e.g. cliff) [contour lines
that are CLOSE to each other]
EVEN / GRADUAL GRADIENT IN SLOPE → if there is a small difference in elevation between
locations, while the horizontal distance between the two locations is far [contour lines
that are FAR apart]
gradient=
*** a small dot ( ⚫ ) > highest point difference in vertical height [m]
horizontal distance [m]
2 © Noted Summaries Grade 9 SS Part 1 : Geography www.notedsummaries.co.za
,RIVER VALLEYS & SPURS:
VALLEY → low-lying land between hills and mountains where rivers flow thickly > ( V
shaped and runs upwards )
SPUR → finger-like pieces of land that run down from a mountain or hill > ( U shaped and
run downwards ) > stone ridges that form the valley
3 © Noted Summaries Grade 9 SS Part 1 : Geography www.notedsummaries.co.za
, ORTHOPHOTO & TOPOGRAPHIC MAPS [MAPWORK]
1 : 10 000 ORTHOPHOTO MAPS
A ORTHOPHOTO MAP > combination between a vertical aerial photograph and a map
→ show us place names, contour lines, elevations, street names and grid lines indicating
the coordinates
INDICATION OF HEIGHT:
Z orthophoto karate has contour lines.
Z they have 5m intervals
Z not all contour lines are numbered
Z dot height [dot with a number > height]
HOW IS AN ORTHOPHOTO MAP MADE?
> using vertical aerial photographs to which information is added [vertical aerial
photographs > record of everything happening on the ground when the photograph was
taken > agriculture / mining & rivers]
> cartographers use computer programs to correct the scale and to correct ambiguities
(rectification > orthophoto which is to scale)
1 : 50 000 TOPOGRAPHIC MAP
TOPOGRAPHIC MAPS → using symbols to identify features to identify features on
topographic maps
→ show different features of the earth's surface
' topographically ' = the shape of the the area shows as well as other features
[scale of topographic maps → 1; 50 000]
[1cm on the map 50,000cm in reality]
INDICATION OF HEIGHT:
GRADE 9 > TERM 1
contour interval on n 1; 50,000 topographic map = always
Contour lines 20m → every fifth contour line is darker brown than the
rest
The darker lines indicate every 100m height difference. To
determine the height of the hill you must count the darker
lines
The numbers on the lines will always be typed so that they
point to the higher parts
it indicates the exact height in meters as a number next
Point height
to a point ( ⚫ )
4 © Noted Summaries Grade 9 SS Part 1 : Geography www.notedsummaries.co.za
, CONTOUR LINES [MAPWORK]
CONTOUR LINES → (contour) lines on a map > connect places of the same height above sea
level [indicate landscape phenomena]
→ symbolic horizontal line indicating height and the shape of the slopesi
→ accurate way to indicate relief on maps [shape, size & steepness]
[relief > shape of the earth's surface > unevenness of the surface]
NOTES:
Z Numbers / figures on the
contour lines > HEIGHT (in
Steep slope Gradual slope meters above sea level)
Z Contour interval > distance
between each contour line
(e.g. 20m)
DIFFERENCE BETWEEN A HILL
AND A RIDGE:
Height (m) ridge > long, narrow & steep
hilltop / mountain range
HILL
RIDGE
STEEP & GRADUAL SLOPES:
[Slope = Gradient]
Gradient > describes how style is a slope [determined by the angle of the slope]
GRADE 9 > TERM 1
STEEP GRADIENT IN SLOPE → if there is a large difference in height between locations,
while the horizontal distance between the two locations is small (e.g. cliff) [contour lines
that are CLOSE to each other]
EVEN / GRADUAL GRADIENT IN SLOPE → if there is a small difference in elevation between
locations, while the horizontal distance between the two locations is far [contour lines
that are FAR apart]
gradient=
*** a small dot ( ⚫ ) > highest point difference in vertical height [m]
horizontal distance [m]
2 © Noted Summaries Grade 9 SS Part 1 : Geography www.notedsummaries.co.za
,RIVER VALLEYS & SPURS:
VALLEY → low-lying land between hills and mountains where rivers flow thickly > ( V
shaped and runs upwards )
SPUR → finger-like pieces of land that run down from a mountain or hill > ( U shaped and
run downwards ) > stone ridges that form the valley
3 © Noted Summaries Grade 9 SS Part 1 : Geography www.notedsummaries.co.za
, ORTHOPHOTO & TOPOGRAPHIC MAPS [MAPWORK]
1 : 10 000 ORTHOPHOTO MAPS
A ORTHOPHOTO MAP > combination between a vertical aerial photograph and a map
→ show us place names, contour lines, elevations, street names and grid lines indicating
the coordinates
INDICATION OF HEIGHT:
Z orthophoto karate has contour lines.
Z they have 5m intervals
Z not all contour lines are numbered
Z dot height [dot with a number > height]
HOW IS AN ORTHOPHOTO MAP MADE?
> using vertical aerial photographs to which information is added [vertical aerial
photographs > record of everything happening on the ground when the photograph was
taken > agriculture / mining & rivers]
> cartographers use computer programs to correct the scale and to correct ambiguities
(rectification > orthophoto which is to scale)
1 : 50 000 TOPOGRAPHIC MAP
TOPOGRAPHIC MAPS → using symbols to identify features to identify features on
topographic maps
→ show different features of the earth's surface
' topographically ' = the shape of the the area shows as well as other features
[scale of topographic maps → 1; 50 000]
[1cm on the map 50,000cm in reality]
INDICATION OF HEIGHT:
GRADE 9 > TERM 1
contour interval on n 1; 50,000 topographic map = always
Contour lines 20m → every fifth contour line is darker brown than the
rest
The darker lines indicate every 100m height difference. To
determine the height of the hill you must count the darker
lines
The numbers on the lines will always be typed so that they
point to the higher parts
it indicates the exact height in meters as a number next
Point height
to a point ( ⚫ )
4 © Noted Summaries Grade 9 SS Part 1 : Geography www.notedsummaries.co.za
