Landform Drawings Chapter 20. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper

Landform Drawings

Chapter 20

2Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

All Rights Reserved.

Objectives

• Read and draw a plat, topographic contour map, street contour map, and highway plan and profile

• Read the elevation of a tract of land using contour lines

• Identify the scale and compass orientation of a topographic map




Objectives (cont.)

• Read and notate property boundaries on a land survey map

• Create a profile map from contour lines




Definitions

• Plat• A map of a small area, plotted from a

land survey• Does not ordinarily show elevations• Drawn to calculate areas, locate

property lines, locate building projects and facilities




Land Survey Plat




Definitions

• Traverse• Consists of a series of intersecting

straight lines of accurately measured lengths

• At the points of intersection, the deflection angles between adjacent lines are measured and recorded




Definitions

• Elevations• Elevations are vertical distances

above a common datum, reference plane, or point

• Commonly, elevations are referenced to mean sea level




Definitions

• Profile• A line contained in a vertical plane

and it depicts the relative elevations of various points along the line

• If a vertical section were to be cut into the Earth, the top line of this section would represent the ground profile




Definitions

• Contours• Contours are lines drawn on a map to

locate, in the plan view, points of equal ground elevation

• On a single contour line, all points have the same elevation




Contours




Definitions

• Hatchures• Short, parallel, or slightly divergent

lines drawn in the direction of the slope

• They are closely spaced on steep slopes and converge toward the tops of ridges and hills




Definitions

• Monuments• Special installations of stone or concrete

to mark the locations of points accurately determined by precise surveying

• Monuments are intended to be permanent

• Cartography• Cartography is the science or art of map

making




Definitions

• Topographic maps depict:• Water• Relief or elevations• Culture or human constructions




Topographic Maps




Definitions

• Hydrographic Maps• These maps convey information

concerning bodies of water• Cadastral maps

• Accurately drawn maps of cities and towns showing property lines and other features that control property ownership




Definitions

• Military maps• Contain information of military

importance• Nautical maps

• Maps and charts showing navigational features and aids

• Aeronautical maps• Maps and charts showing prominent

landmarks used for air navigators




Definitions

• Engineering maps• Made for special projects as an aid to

locations and construction• Landscape maps

• Used in planning installations of trees, shrubbery, drives, and other garden features




Getting Information for Maps• Several surveying methods are used

to obtain the information necessary to make a map including:• Electronic survey instruments• Geographic positioning system (GPS)

receivers• Photogrammetry and satellites imagery




Getting Information for Maps• (cont.)

• Laser distance meters• Optical mechanical systems• Steel tape• Scaled measurements




Symbols




Bearings

• The bearing of a line is its angle from magnetic north

• Bearings are listed by referencing the angle the line makes departing from either the North or South toward either the East or West




Bearings




Elevation

• If GPS is not used to provide elevation, an optical instrument called a level, equipped with a telescope for sighting long distances can be used to determine differences in elevation

• This process is called differential leveling




Contours

• Contours are map lines showing points of equal ground elevation

• A contour interval is the vertical distance between horizontal planes passing through successive contours

• It is customary to show every fifth contour with a heavier line




City Maps




Subdivision Plats




Landscape Drawings




Structure Location Plans

• These maps are used to plan construction projects to locate construction features so they fit the topography of the area




Structure Location Plans




Highway Plans

• Before highway construction starts, it is necessary to plan the horizontal and vertical location and alignments

• Commonly both the plan view and profile are drawn on the same sheet




Highway Plans




United States Maps

• Maps of the United States prepared by the U.S. Coast and Geodetic Survey and the U.S. Geological Survey are excellent examples of topographic mapping

• Maps at large scales, such as 1:62,500, can only show the main features of terrain




United States Maps

Documents

Landform Drawings Chapter 20. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper