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

**FIRST DEPRESSION LINE TAKES THE VALUE OF THE CONTOUR LINE SURROUNDING IT

THE “WHISKERS” POINT TO THE LOWER ELEVATION

A BENCHMARK POINT IS A LOCATION WHOSE EXACT ELEVATION IS KNOWN AND IS NOTED ON A BRASS ALLUMINUM PLATE ( BM )

A  MAXIMUM ELEVATION- HIGHEST 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)

RELIEF- DIFFERENCE IN ELEVATION

RELIEF MAP – RAISED MAP WHICH SHOWS DIFFERENCE IN ELEVATION(3-D)

PROFILE- SIDE VIEW OF THE SHAPE OF THE LAND ON A TOPOGRAPHIC MAP