Lab 2 – Topographic Maps & Land Navigation

Maps/Coordinate Systems ► Represent spatial relationship of things and shape of landscape ► Must have frame of reference (coordinate system) to describe positions that is easy to interpret ► All coordinate systems necessarily relative to something  Better to have something permenant and unique

UTM ► UTM – Universal Transverse Mercator ► Based on grid of 60 zones (running N-S) ► Grid lines run N-S and E-W  Easting = X coordinate = is the distance to the "False easting,” which is uniquely defined in each UTM zone (verticle lines)  Northing = Y coordinate = the distance to the equator (horizontal lines)  Any point respresented as: Zone, Easting, Northing

UTM Zones

Bearing ► Bearings : compass direction along a line between 2 points ► Based on 4 cardinal directions  Full circle = 360  90° between N, S, E, W

Bearing ► True north (pole of rotation) v. magnetic north  Declination ► 2 formats for bearing  Azimuth (0 = north, 90 = east, 180 = south, 270 = west)  Quadrant (bearings are in 1 of 4 quadrants: E of N, W of N, E of S, W of S) ► Bearings read as angle between 0-90 away from N or S, e.g., 30 degrees E of S (=150 in azimuth)

Topographic maps ► Not only interested in only the horizontal distance between points…also want to know the vertical relationship of points  Hills, valleys, etc. ► Topo maps are a 2D way to respresent 3D surfaces ► Shown via contour lines => lines of equal elevation

Topographic maps ► See page 174 for rules of contour lines! ► Some examples...  Closed contour lines indicate hilltops  Closed contour lines with hatch marks indicate depressions  Contour lines V upstream when crossing a valley  Contour lines never cross!

Depression Tightly space contours – Steep incline Contours V upstream Hilltop