TOPOGRAPHIC MAP
A MAP WHICH SHOWS ELEVATION OF
THE LAND WITH THE USE OF
CONTOUR LINES, SHAPES , AND
SYMBOLS
CONTOUR LINES
LINES DRAWN TO CONNECT
POINTS OF THE SAME ELEVATION
ELEVATION
CONTOUR INTERVAL- THE
DIFFERENCE IN ELEVATION
BETWEEN TWO CONSECUTIVE
CONTOUR LINES
INDEX CONTOUR- EVERY
FOURTH OR FIFTH LINE WHICH IS
DARKENED FOR EASY READING
STEEPNESS OF SLOPES
CLOSER CONTOUR LINES = STEEP
SLOPES
WELL-SPACED CONTOUR LINES = FLATTER,
GENTLE SLOPES
THE SHAPE OF THE LAND
AT VARIOUS HEIGHTS
( SINKHOLE, QUARRY, MINE)
MEASURED USING A HACHURE LINE
THE “WHISKERS” POINT TO THE
LOWER ELEVATION
**FIRST DEPRESSION LINE TAKES THE
VALUE OF THE CONTOUR LINE
SURROUNDING IT
A BENCHMARK POINT IS A
LOCATION WHOSE EXACT
ELEVATION IS KNOWN AND IS
NOTED ON A BRASS ALLUMINUM
PLATE ( BM )
A MAXIMUM ELEVATIONHIGHEST POSSIBLE ELEVATION
FIGURE OUT WHAT THE NEXT POSSIBLE
CONTOUR LINE WOULD BE THEN
SUBTRACT 1 UNIT
MINIMUM ELEVATION- LOWEST
POSSIBLE ELEVATION
THE NEXT POSSIBLE DEPRESSION LINE, THEN
PLUS 1 UNIT
RIVERS CUT A VALLEY AND CAUSE
CONTOUR LINES TO FORM A V-SHAPE
POINTING TO THE SOURCE OF THE
STREAM (UPSTREAM).
GRADIENT = CHANGE IN ELEVATION (ft)
DISTANCE
(mi)
PROFILE- SIDE VIEW OF
THE SHAPE OF THE LAND
ON A TOPOGRAPHIC MAP
RELIEF- DIFFERENCE IN ELEVATION
RELIEF MAP – RAISED MAP WHICH
SHOWS DIFFERENCE IN ELEVATION(3-D)