Topographic MapsTopographic Maps

Topographic maps model the changes in Topographic maps model the changes in Earth’s elevation.Earth’s elevation.

How are topographic How are topographic maps useful?maps useful?

Determine your location relative to Determine your location relative to identifiable natural features identifiable natural features

Topographic maps also indicate cultural Topographic maps also indicate cultural features such as roads, cities and damsfeatures such as roads, cities and dams

Often used by hikersOften used by hikers

What is a contour line? What is a contour line? A line on a map that connects points of A line on a map that connects points of

equal elevation.equal elevation.

What is a contour interval?What is a contour interval? The difference in elevation between two The difference in elevation between two

side-by-side contour lines.side-by-side contour lines. This # is constant for each mapThis # is constant for each map

What can you tell from What can you tell from contour lines?contour lines?

Contour lines that are close together = Contour lines that are close together = steep elevationsteep elevation

-Mountains, ridges, valleys-Mountains, ridges, valleys

Contour lines that are far apart =Contour lines that are far apart =

slight change in elevation.slight change in elevation.

What is an index What is an index contour?contour?

A contour line that is marked with the A contour line that is marked with the elevation number.elevation number.

How are index contours How are index contours useful?useful? You can determine the elevation of other You can determine the elevation of other

lines around the index contour by adding lines around the index contour by adding or subtracting the contour interval or subtracting the contour interval number.number.

Contour lines always Contour lines always point upstream on rivers.point upstream on rivers.

Basins and craters are Basins and craters are represented with hachuresrepresented with hachures

What do different colors What do different colors indicate on topo. Maps?indicate on topo. Maps?

Green = area with vegetationGreen = area with vegetation White = area with little to no vegetationWhite = area with little to no vegetation

Cities, deserts, etc.Cities, deserts, etc.

Purple = dark - revisions to the mapPurple = dark - revisions to the map

light - urban areaslight - urban areas

Map ScalesMap Scales

The relationship between the distances The relationship between the distances on the map and distances on Earth’s on the map and distances on Earth’s surface.surface.

Scale is often represented as a ratio.Scale is often represented as a ratio. Example: 1:80Example: 1:80

This means that one unit on the map This means that one unit on the map represents 80 units on land.represents 80 units on land.

The unit of distance could be feet, miles, The unit of distance could be feet, miles, millimeters, etc.millimeters, etc.

Map LegendsMap Legends

Topographic maps and most other maps Topographic maps and most other maps have a legend.have a legend.

A map legend explains what the symbols A map legend explains what the symbols used on the map mean.used on the map mean.

Some frequently used symbols on Some frequently used symbols on topographic maps are shown in the topographic maps are shown in the appendix in the back of your book on appendix in the back of your book on

p. 806p. 806

Map SeriesMap Series

A map series includes maps that have A map series includes maps that have the same dimensions of latitude and the same dimensions of latitude and longitude. longitude.

For example, one map series includes For example, one map series includes maps that are 7.5 minutes of latitude by maps that are 7.5 minutes of latitude by 7.5 minutes of longitude.7.5 minutes of longitude.