Unit 2- Dimensions of

the Earth





Latitude and Longitude

Latitude and Longitude are imaginary lines that we use for orientation and locations on maps.

Longitude runs from North to South, and Latitude runs from East to West.


To find Longitude measurements look at the numbers on the top of the topographic map.

To find Latitude, see the numbers on the side of the map.

The latitude is written before the longitude. Ex. 41oN, 73oW.

Remember: There are 60 " (seconds) in a minute and 60 ' (minutes) in a degree.

ex. 30 1/2 degrees N= 30o30'N not 30o50'N

Video on Latitude and Longitude

NY State Latitude and Longitude


Topographic Maps

A topo (topographic) map is a map that shows elevation. It's THE map to bring when going wilderness hiking.

Contour lines show elevation above sea level. The amount of elevation change between each contour line is called a contour interval.

Augmented Reality Sandbox

Drawing Isolines

Practice video

Intro to Topographic Maps


Rules of Contours

The closer together the contour lines the steeper the slope.

Contour Lines (or any other isolines for that matter) don't cross or branch with another contour line.

Where contour lines make a bull's eye- a series of concentric circles, there is a hill top.

When a contour lines crosses a river/stream it makes a "V". The point of the "V" points uphill. So the river is flowing the opposite way.

Stream flow YouTube



The gradient is the same thing as slope. It gives us a 3-d picture of what the land would look like.

Gradient= Change in elevation/ Change in distance.

1. Change in elevation- Find the elevation of the beginning and ending points and subtract

2. Change in distance- On a piece of paper (side of the reference tables), mark how far apart the two locations are. Now find out how long that is using the scale. Scales don't always start at zero so watch out.


Gradient of a Slope YouTube


Cross Section

How to Draw a Topographic Profile

Profile Diagram