Topographic Maps

90 degrees each way to poles
aka parallels
1 min
60 sec
1 degree
60 min
great circles
divides the globe in half
great circles
formed by two meridians of longitude
aka meridians
magnetic compass
used to earth’s magnetic field at an angle to the earth’s axis of rotation
geomagnetic poles
points on the earth’s surface above the imaginary magnet
magnetic declination
angle between the direction of the geographic pole and the directon a compass points
contour interval
interval between one contour and the next
index line
a bolded contour