Definition of Topographic Maps 1. A graphical representation of the three dimensional shape of the earth’s surface. 2. A reduced, simplified representation of the earth’s surface which has been projected on a horizontal plane.

Features of Topographic Maps TOPOGRAPHY (RELIEF): - printed in brown - contour lines shows hills, mountains, plains, etc. WATER FEATURES: - printed in blue - includes oceans, lakes, ponds, rivers, canals, etc.

Features of Topographic Maps Relationship between 3D and 2D representation 3D view 2D view

Title and Location MAP TITLE

Title and Location QUADRANGLE LOCATION

Map design Other Information

Earth's Surface Location Coordinates A location on the surface of the earth is most easily described by angle such as: - Lines of parallel - latitude (angle from equator) - Lines of meridians -longitude (angle from Greenwich, England) So: Latitudes are lines drawn on the globe parallel to the equator. Longitudes are circles drawn on the globe that pass through the two poles.

Latitude and Longitude Generalized system of meridians and parallels

Projection DEFINITION The process of constructing a map involves the transfer of the meridians and parallels to a flat sheet of paper. The resulting product is called a 'map projection'. This can be done in a wide variety of ways, the principle differences being projections that show accurate area over the entire map, and those that show accurate distance.

Projections: Equal Distance vs. Area Equal Area Cylindrical Equidistant Cylindrical

Orthographic Projection: Orbital View Othographical

Time Zones of the Lower 48

Contour lines DEFINITION A contour line is an imaginary line on the surface of the earth connecting points of equal elevation. Topography is the configuration of the land surface and is shown by means of contour lines. The contour interval (C.I.) is the difference in elevation between any two adjacent contour lines.

Contour lines Relationship between topographic features and contour lines

General Features of Contour Lines - contour lines connect points of equal elevation - steep slopes are shown by closely spaced contour lines - gentle slopes are shown by widely spaced contour lines contour lines do not intersect, branch or cross

Contour Lines when contour lines cross streams they bend upstream; the contour line forms a 'V‘ pointing in an upstream direction. closed contours appearing on the map as ellipses or circles represent hills or knobs. closed contours with hatchures, (short lines pointing toward the center) represent closed depressions.

- It graphically represents the 'skyline' as viewed from a distance. Topographic Profiles - A topographic profile is a diagram that shows the change in elevation of the land surface along any given line. - It graphically represents the 'skyline' as viewed from a distance.

Topographic Profile

Topographic Profile Constructing a Topographic Profile