map reading
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MAP READINGMAP READINGCXC GEOGRAPHYCXC GEOGRAPHYWORKSHOP 2009WORKSHOP 2009
MS. K. BROWN
IMPORTANCE OF MAP IMPORTANCE OF MAP READING IN THE EXAMREADING IN THE EXAM
• MAP READING IS COMPULSORY IN THE EXAM
• IT IS THE ONLY COMPULSORY QUESTION.
• IT CAN MAKE THE DIFFERENCE BETWEEN EXAM GRADES 1 OR 2.
• IT CAN MAKE THE DIFFERENCE BETWEEN PASS AND FAIL
• 28% OF THE MARKS IN THE EXAM IS OBTAINED FROM MAP READING
TOPICSTOPICS• LOCATING PLACES USING GRID
REFERENCE• FINDING THE BEARING OF PLACES• CALCULATING GRADIENT OF
SLOPES• MEASURING DISTANCES WITH
SCALES• DRAWING AND INTERPRETING
CROSS SECTIONS
TOPICS TOPICS CONT’DCONT’D
• DRAWING OF SKETCH MAPS• DESCRIBING LANDFORMS FROM
MAPS• DESCRIBING DRAINAGE NETWORKS• DESCRIBING LANDUSE• DESCRIBING THE INFLUENCE OF
LANDFORM ON MAN’S ACTIVITIES (SETTLEMENT,
AGRICULTURE, TRANSPORT NETWORK
GRID REFERENCEGRID REFERENCE• TOPOGRAPHIC MAPS ARE DIVIDED
INTO GRIDS.• THESE GRIDS HELP US TO LOCATE
PLACES EASIER• GRID LINES ARE NUMBERED LINES
ON A MAP• THE VERTICAL GRID LINES ARE
CALLED EASTINGS• HORIZONTAL GRID LINES ARE
CALLED NORTHINGS
22 23 24 25
11
12
13
EASTING
N O R T H I N G
2211
2212
READ THE GRID REFERENCE IN THE FORM OF LETTER ‘L’
GRID REFERENCEGRID REFERENCE
• THERE IS THE FOUR FIGURE GRID REFERENCE
• EG. 2211, 2212• EASTINGS ARE ALWAYS WRITTEN
BEFORE NORTHINGS• THE FIRST TWO NUMBERS ARE THE
EASTING AND THE LAST TWO NORTHING
GRID REFERENCEGRID REFERENCE
• THERE IS ALSO SIX FIGURE GRID REFERENCE
• THE SIX FIGURE GRID REFERENCE IS USED TO GIVE MORE PRECISE LOCATIONS
• TO GIVE THE SIX FIGURE GRID REFERNCE DIVIDE EACH GRID BOX INTO TEN EQUAL PARTS ON EACH SIDE
• NUMBER EACH LINE 1-9
22 23 24
11
12
13
1 2 3 4 5 6 7 8 9
987654321
221116
224113
25
5
5
241119
247111
GRID REFERENCEGRID REFERENCE
• WHAT IS THE FOUR FIGURE GRID REFERENCE OF:(a) SPRING VILLAGE(b) BUSHY PARK(c) MC COOKS PEN
GRID REFERENCEGRID REFERENCE
FOUR FIGURE GRID REFERENCE
•5237•5238•5338
GRID REFERENCEGRID REFERENCE
• WHAT IS THE SIX FIGURE GRID REFERENCE OF:(a) THE TRIGONOMETRY STATION
AT BUSHY PARK(b) SCHOOL IN SPRING VILLAGE
(C) POSTAL AGENCY NEAR CHURCH PEN
(d) THE BRIDGE THAT CROSSES THE SPRING GARDEN RIVER
GRID REFERENCEGRID REFERENCE
SIX FIGURE GRID REFERENCE
• 527371
• 519378
• 524385
• 535384
SCALESSCALES
•THREE TYPES OF SCALES ARE REPRESENTED ON TOPOGRAPHIC MAPS
•LINEAR SCALE•REPRESENTATIVE FRACTION
•DIRECT STATEMENTS
SCALESSCALES
• LINEAR SCALE-A BAR DIVIDED INTO SECTIONS
• THIS SCALE CAN BE REPRESENTED IN ANY UNIT (MILES, KILOMETRES, METRES,YARDS, FEET
SCALESSCALES• REPRESENTATIVE FRACTION-
WRITTEN AS A RATIO. FOR EG.• 1:50,000• THIS MEAN 1UNIT ON THE MAP
REPRESENTS 50,000 UNITS ON THE GROUND
OR1:25,000
THIS MEANS 1 UNIT ON THE MAP REPRESENTS 25,000 UNITS ON THE GROUND
SCALESSCALES
•DIRECT STATEMENTS - WRITTEN IN WORDS. FOR EG.
•1CM REPRESENT 50,000CM
OR•1CM REPRESENT 1KM
SCALESSCALES• FUNCTIONS:• USED TO MEASURE DISTANCES OF ROADS, RIVERS, RAILWAYS, LANDFORMS.
THESE FEATURES CAN BE MEASURED AS • STRIGHT LINE DISTANCES (LINE DRAWN
BETWEEN THE TWO POINTS AND THEN MEASURED.
• ACTUAL DISTANCES (THE ENTIRE DISTANCE ALONG THE FEATURE IS MEASURED USING A STRING OR PAPER.
SCALESSCALES
• USING THE LINEAR SCALE:• PLACE A STRIP OF PAPER ALONG THE
LENGTH OF THE FEATURE (ROAD, RIVER)
• USE A PENCIL TO MARK OFF EACH STRAIGHT PORTION OF THE FEATURE
• PIVOT THE PAPER USING THE PENCIL UNTIL YOU ARE AT THE END OF THE FEATURE
SCALESSCALES
• WHEN FINISHED PLACE THE STRIP OF PAPER ALONG THE LINEAR SCALE.
• YOUR STARTING POINT MUST BE AT 0
• RECORD THE VALUE OF THE DISTANCE OF THE FEATURE
• DO NOT FORGET TO WRITE DOWN THE UNIT OF THE DISTANCE THAT YOU MEASURED IN. FOR EG. KM, MILES, METRES.
1000750
500250
0
Metre
1 2 3
X start here Kilometre
•PAY CLOSE ATTENTION TO THE UNIT OF THE SCALE
SCALESSCALES
• USING THE REPRESENTATIVE FRACTION 1:50,000
• USE A RULER TO MEASURE THE DISTANCE BETWEEN THE TWO POINTS
• THE VALUE OBTAINED (EG.5CM) MUST BE MULTIPLED BY THE NUMBER TO THE RIGHT OF THE COLON. (5X50,000)
SCALESSCALES
• 5X50,000=250,000CM
• IF THE ANSWER IS TO BE IN KM DIVIDE YOUR ANSWER BY 100,000 (100,000CM=1KM)
• 250,000 DIVIDED BY 100,000=2.5KM
SCALESSCALES
• HOW TO SPEED IT UP?• USE A THUMB TACK (THE
COLOURED ONE) AND STICK IT IN THE STRIP OF PAPER THAT IS USED TO MEASURE THE DISTANCE
• TURN THE PAPER AS YOU MEASURE AND MOVE THE THUMB TACK ALONG THE PAPER
SCALESSCALES
• CONVERSIONSIMPERIAL UNITS3 FEET = 1YARD5,280 FEET = 1 MILE1760 YARDS= 1 MILE
BEARINGSBEARINGS
• THIS IS THE ANGULAR DISTANCE OF ONE PLACE X FROM ANOTHER Y
• BEARINGS ARE CALCULATED BY THE USE OF A PROTRACTOR.
BEARINGSBEARINGS
• HOW TO CALCULATE BEARINGS1. DRAW A LINE BETWEEN THE
TWO POINTS
X
Y
BEARINGSBEARINGS
2. DRAW A VERTICAL LINE THROUGH THE POINT FROM WHICH YOU ARE TAKING THE BEARING.
FOR EG. WHAT IS THE BEARING OF X FROM Y
DRAW THE VERTICAL LINE THROUGH POINT Y
BEARINGSBEARINGS
3. PLACE THE PROTRACTOR ON THE VERTICAL LINE
4. STARTING FROM 0º IN A CLOCKWISE DIRECTION, MEASURE THE ANGLE BETWEEN THE VERTICAL LINE AND THE LINE DRAWN BETWEEN THE TWO POINTS
BEARINGSBEARINGS
• EXERCISE(a)WHAT IS THE BEARING OF THE
NEGRIL LIGHTHOUSE FROM THE YATCH CLUB
(b)GIVE THE BEARING OF THE YOUTH CENTRE FROM THE CHURCH NEAR SILVER SPRING
BEARINGSBEARINGS
• HOW TO SPEED IT UP?• USE THE PROTRACTOR THAT IS
COMPLETE AS A CIRCLE• DRAW LONG VERTICAL AND
CONNECTING LINES.• USE SHARP PENCILS!!! DULL
PENCILS CAN GIVE ERROR UP TO 3º
GRADIENTGRADIENT
• THE RATE OF CHANGE OF A SLOPE
• THE DEGREE OF SLOPE
DEGREE OF SLOPE
GRADIENTGRADIENT• THE MATHEMATICIAN VS GEOGRAPHER
GRADIENT AS FRACTION AS RATIO1/20 1:20RISE/RUNRISE:RUN
THESE ARE INTERPRETED THE SAME WAYTHE GEOGRAPHER IS SAYING RUN IS 20
TIMES LONGER THAN RISE.
GRADIENT
1CM
20CM RUN
SLOPERISE
GRADIENTGRADIENT• GRADIENT IN THE FIRST PHOTO
IS VERY HIGH ALMOST VERTICAL.1:0
GRADIENT IN THE SECOND PHOTO IS MODERATE 1:75
GRADIENT IN THE THIRD PHOTO IS VERY LOW, GENTLE, ALMOST FLAT
1:270
270m
1m
GRADIENTGRADIENT• THE NUMBER TO THE LEFT OF THE COLON
INDICATE THE VALUE OF THE VERTICAL HEIGHT (THAT IS THE RUN)
• THE NUMBER TO THE RIGHT OF THE COLON INDICATE THE VALUE OF THE HORIZONTAL DISTANCE ON THE GROUND
(THAT IS THE RISE)
• THE SMALLER THE NUMBER TO THE RIGHT OF THE COLON, THE STEEPER THE GRADIENT
GRADIENTGRADIENT
•FOR EG.1:75 IS STEEPER THAN 1:270
LOOK BACK AT THE GRADIENTS IN THE PHOTOS
GRADIENTGRADIENT
•HOW TO CALCULATE GRADIENT?
•PRE-REQUISITE:•YOU MUST BE ABLE TO
CALCULATE DISTANCE•YOU MUST UNDERSTAND
CONTOUR INTERVALS
GRADIENTGRADIENT
•TO CALCULATE GRADIENT:YOU NEED THE DIFFERENCE IN
HEIGHT BETWEEN THE TWO POINTS (A-B)
ANDTHE HORIZONTAL DISTANCE
BETWEEN THE TWO POINTS
GRADIENTGRADIENT
• THE SCHOOL AT MAIDEN STONE IS 320METRES , THE HEIGHT OF THE COAST NEAR RIO GRANDE IS SEA LEVEL, THE STRAIGHT LINE DISTANCE IS 5KM CALCULATE THE AVERAGE GRADIENT
A
B
HORIZONTAL DISTANCE
GRADIENTGRADIENTDIFFERENCE IN VERTICAL HEIGHT
HORIZONTAL DISTANCE• THE VERTICAL DISTANCE IS
OBTAINED BY SUBTRACTING THE SMALLER CONTOUR OR SPOT HEIGHT VALUE FROM THE HIGHER
• HORIZONTAL DISTANCE IS MEASURED AGAINST THE SCALE
GRADIENTGRADIENT
• AFTER OBTAINING THE TWO VALUES
CONVERT BOTH TO THE SAME UNITS
THAT IS THE VERTICAL DIFFERENCE MUST BE IN THE SAME UNIT AS THE HORIZONTAL DISTANCE.
FOR EG. 400M-200M=200M (VERTICAL DIFFERENCE)
HORIZONTAL DISTANCE =600M
GRADIENTGRADIENT
200:600THIS IS SAYING THAT THE LAND
RISE BY 200M OVER A DISTANCE OF 600M
• THE NEXT STEP IS TO DIVIDE THE NUMBER TO THE LEFT OF THE COLON INTO ITSELF
• THEN INTO THE NUMBER TO THE RIGHT OF THE COLON
GRADIENTGRADIENT
• 200/200 : 600/200
1 : 3 ANSWER !!!INTERPRETATION
FOR EVERY 3M HORIZONTALLY ALONG THE GROUND THE LAND RISES BY 1 M
THIS IS A GENTLE SLOPE
GRADIENTGRADIENTTHE HEIGHT OF THE SCHOOL AT MAIDEN THE HEIGHT OF THE SCHOOL AT MAIDEN STONE (0167)IS 320METRES STONE (0167)IS 320METRES
THE HEIGHTOF THE COAST NEAR THE THE HEIGHTOF THE COAST NEAR THE RIO GRANDE BRIDGE IS APPROX. 0 RIO GRANDE BRIDGE IS APPROX. 0 METRESMETRES
THE DISTANCE IN A STRAIGHT LINE THE DISTANCE IN A STRAIGHT LINE BETWEEN THE TWO POINTS IS 5KMBETWEEN THE TWO POINTS IS 5KM
CALCULATE THE AVERAGE GRADIENTCALCULATE THE AVERAGE GRADIENT
CROSS SECTIONCROSS SECTION• THIS IS A VERTICAL CUT
THROUGH A LANDFORM TO SHOW A PROFILE
• THE CROSS SECTION IS DRAWN BY A LINE GRAPH SHOWING HEIGHT AGAINST HORIZONTAL DISTANCE
• THE HEIGHT IS OBTAINED FROM THE CONTOUR LINES
CROSS SECTIONCROSS SECTION
• HOW TO DRAW A CROSS SECTION
1. IDENTIFY YOUR STARTING AND ENDING POINTS
2. DRAW A STRAIGHT LINE TO CONNECT THESE TWO POINTS
3. USING A STRIP OF BLANK PAPER MARK OFF WHERE ALL THE CONTOURS CROSS THE LINE OF SECTION
CROSS SECTIONCROSS SECTION
4. NUMBER THE CONTOURS ON YOUR STRIP OF PAPER
5. IN YOUR BOOK, DRAW A LINE THE SAME LENGTH AS THE SECTION
6. PLACE YOUR STRIP OF PAPER ALONG THIS LINE AND MARK OFF THE CONTOURS AND RECORD THE VALUE
CROSS SECTIONCROSS SECTION
7. DEVELOP A VERTICAL SCALE TO RECORD THE HEIGHT
8. USING SMALL X’S MARK THE POINT ON THE VERTICAL THAT CORRESPOND TO THE HORIZONTAL
9. DRAW A LINE CONNECTING THE X’S TO COMPLETE THE CROSS SECTION
x
y
200
250
300
345000
450
500
550
600
650
700
750
0
100
200
300
400
500
600
700
800
X
X
X
X
X
X
X
XX
XX
X
CROSS SECTION
XY
CROSS SECTIONCROSS SECTION
• HOW TO SPEED IT UP?• IDENTIFY YOUR LINE OF SECTION• DRAW A LINE EQUAL TO ITS
LENGTH ON YOUR PAPER• DEVELOP A VERTICAL SCALE• FOLD THE MAP ALONG THE LINE
OF SECTION
CROSS SECTIONCROSS SECTION
• PUT THE FOLDED SECTION ALONG THE LINE YOU DREW
• NOTE THE VALUE OF EACH CONTOUR
AND PUT IN THE POINTS (THAT IS THE X’S)
• CONNECT THEM TO COMPLETE THE SECTION
CROSS SECTIONCROSS SECTION
• YOU MAY ALSO GET A DRAWN CROSS SECTION IN THE EXAM
• THIS IS WHERE YOU HAVE TO LABEL THE CROSS SECTION WITH THE CORRESPONDING FEATURES ON THE MAP
DESCRIBING THE DRINAGEDESCRIBING THE DRINAGE
• WE ARE DESCRIBING THE GEOMETRY FORMED BY THE DRAINAGE LINES
• THE GEOMETRY OF THE DRAINAGE CAN TAKE ANY OF THE FOLLOWING PATTERN
• DENDRITIC• RADIAL• TRELLIS
DRAINAGEDRAINAGE
• WHEN THE DRINAGE IS DENDRITIC, THE TRIBUTARIES JOIN THE MAIN STRAM AT ACUTE ANGLES
• DEVELOP IN REGIONS WITH A UNIFORM ROCK STRUCTURE (ROCKS ARE OF THE SAME TYPE)
DRAINAGE
DRAINAGEDRAINAGE
• THE TRELLIS DRAINAGE PATTERN HAS TRIBUTARIES JOINING THE MAIN STREAM AT RIGHT ANGLES
• DEVELOP IN REGIONS THAT HAVE ALTERNATING BANDS OF HARD AND SOFT ROCKS
DRAINAGE
DRAINAGEDRAINAGE
• THE RADIAL DRAINAGE PATTERN HAS TRIBUTARIES FLOWING IN AN OUTWARD DIRECTION FROM A CENTRAL AREA. (LIKE THE SPOKES OF A WHEEL)
• STREAMS RADIATE FROM A HILL OR VOLCANIC DOME
DRAINAGE
DRAINAGEDRAINAGE
• HOW TO DESCRIBE THE DRAINAGE OF AN AREA?
1. FIRST IDENTIFY THE DOMINANT DRAINAGE PATTERN ON THE AREA. FOR EG. RADIAL
2. NEXT LOOK FOR ANY SMALLER DRAINAGE PATTERN OF INDIVIDUAL STREAM.
3. MAKE SURE TO GIVE THE GRID REFERENCE FOR THEIR LOCATION
DRAINAGEDRAINAGE
4. DESCRIBE THE DIRECTION OF FLOW OF THE MAIN STREAM.
THE FLOW IS FROM HIGH CONTOUR VALUES TO LOW VALUES
5. DESCRIBE THE NATURE OF THE STREAM
THIS IS WHETHER THE RIVERS ARE SEASONAL OR PERMANENT
THIS IS SHOWN IN THE KEY
DRAINAGEDRAINAGE
6. DESCRIBE THE NATURE OF THE VALLEY-THIS MEANS SAYING WHETHER THE VALLEY IS NARROW OR WIDE, GENTLE OR STEEP SIDED
THIS IS OBTAINED FROM THE SHAPE OF THE CONTOUR LINES
DRAINAGEDRAINAGE
7. DESCRIBE WHETHER THE MAIN RIVER COURSE IS STRAIGHT OR MEANDERING
8. DESCRIBE CHANNEL FEATURES SUCH AS WATERFALLS, RAPIDS (SHOWN IN THE KEY) OR RAPIDS
DRAINAGEDRAINAGE
9. DESCRIBE THE DRAINAGE DENSITY
THIS IS THE NUMBER OF STREAMS WITHIN THE AREA.
IF THERE ARE MANY STREAMS THE DRAINAGE DENSITY IS HIGH
IF THERE ARE FEW STREAMS THE DRAINAGE DENSITY IS LOW
DESCRIBING LANDFORMSDESCRIBING LANDFORMS
THIS IS DESCRIBING FEATURES SUCH AS MOUNTAINS, HILLS, VALLEYS AND PLAINS ON THE MAP
• WHAT INFORMATION DO YOU USE?• CONTOUR VALUES• CONTOUR SHAPES• CONTOUR SPACING• CONTOUR ORIENTATION• SCALE ON THE MAP
LANDFORMSLANDFORMS• WHAT ARE YOU DESCRIBING ABOUT
THE LANDFORM?• HEIGHT OR DIFFERENCES IN HEIGHT
THIS IS BASED ON THE CONTOUR VALUES
• SHAPE OF THE LANDFORM THIS IS BASED ON THE SHAPE OF THE
CONTOURS• SIZE OF THE LANDFORM BASED ON THE SCALE
LANDFORMSLANDFORMS
• LIST OF LANDFORMS• MOUNTAIN• VALLEY• HILL• PLAIN• PLATEAU• ESCARPMENT• GAP/PASS
LANDFORMS
• COASTAL LANDFORM• STEEP CLIFFED AREA TO THE
EAST• GENTLE SLOPING COASTAL AREA
IN THE WEST
LANDFORM AND LANDFORM AND SETTLEMENTSETTLEMENT
• FLAT AREAS HAVE HIGH POPULATION DENSITY
• STEEP SLOPES AND THE HILLY REGIONS ARE SPARSELY POPULATED
• FLAT AREAS USUALLY HAVE A NUCLEAR AND LINEAR SETTLEMENT
• HILLY AREAS HAVE A DISPERSED OR ISOLATED SETTLEMENT
LANDFORM AND LANDFORM AND AGRICULTUREAGRICULTURE
• AGRICULTURAL ACTIVITIES ARE CONCENTRATED ON AREAS OF LOW RELIEF. (SUGAR CANE FOR EXAMPLE ARE PLANTED ON FLAT AREAS
COCONUTS ARE GROWN IN AREAS WITH HIGHER RELIEFS
RELIEF AND TRANSPORT RELIEF AND TRANSPORT NETWORKNETWORK
• MAIN ROADS (‘A’ CLASS ROADS) ARE LOCATED IN FLAT AREAS
• THESE ROADS ARE STRAIGHTER IN APPEARANCE
• TRACKS FOOTPATHS AND MINOR ROADS ARE LOCATED IN HILLY AREAS
• THESE ROADS ARE MORE WINDING
• YOU MAY ALSO BE ASKED TO DESCRIBE THE SETTLEMENT OF AN AREA
• DESCRIBE THE TRANSPORT NETWORK
• DESCRIBE THE VEGETATION• DESCRIBE THE CULTIVATION
• YOU MUST REMEMBER TO GIVE THE GRID REFERENCE OF THE AREA THAT YOU ARE DESCRIBING.
FOR EXAMPLE, LINEAR SETTLEMENT IS LOCATED IN GRID BOX 3325
• YOU MUST ALSO STATE THE NAME OF THE PLACE
FOR EXAMPLE, SAVANNA-LA MAR IS DENSELY POPULATED
SKETCH MAPSSKETCH MAPS
• A GRID IS USUALLY GIVEN TO DRAW THE SKETCH MAP OF A GIVEN AREA
• YOU MAY BE REQUIRED TO DRAW THE MAP ON A LARGER OR SMALLER SCALE.
SKETCH MAPSSKETCH MAPS
• YOU MUST LABEL THE GRID LINES
• DRAW THE FEATURES THAT ARE ASKED TO BE DRAWN
• HAVE A KEY• TITLE• NORTH ARROW
SKETCH MAPSSKETCH MAPS
• YOU SHOULD FIRST LABEL THE GRID LINES PROVIDED.
• CAREFULLY LOCATE THE FEATURES THAT YOU ARE REQUIRED TO INSERT.
• DRAW EACH FEATURE ACCURATELY.
• INSERT A KEY TO REPRESENT THE FEATURES.
DESCRIBING VEGETATIONDESCRIBING VEGETATION
• DESCRIBE THE TYPE OF VEGETATION
• USE GRID REFERENCE, COMPASS DIRECTIONS AND NAMES OF TOWNS TO GIVE THE LOCATION OF EACH TYPE OF VEGETATION YOU DESCRIBE.
• DESCRIBE THE EXTENT OF THE VEGETATION (LARGE AREA,PATCH, POCKET ETC.)
DESCRIBING VEGETATION DESCRIBING VEGETATION CONTDCONTD
• DESCRIBE THE ELEVATION FOR EACH VEGETATION TYPE
• REMEMBER THAT THE VEGETATION IS NATURAL DO NOT CONFUSE IT WITH CULTIVATION.
• TYPES INCLUDE FOREST, TREES AND SCRUBS. MANGROVES, WOODLAND.