Topographic Maps

TOPOGRAPHIC MAP CONTOUR LINES 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

THREE THINGS CONTOUR LINES SHOW US 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

THE SHAPE OF THE LAND AT VARIOUS HEIGHTS STEEPNESS OF SLOPES CLOSER CONTOUR LINES = STEEP SLOPES WELL-SPACED CONTOUR LINES = FLATTER, GENTLE SLOPES THE SHAPE OF THE LAND AT VARIOUS HEIGHTS

ELEVATIONS OF LAND BELOW SEA LEVEL ( 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

INFORMATION LEARNED FROM A TOPOGRAPHIC MAP 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)

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)