Journals – 1-28-14Journals – 1-28-14

Draw a picture of this in your journal.Draw a picture of this in your journal.

Now draw an aerial view of the island Now draw an aerial view of the island and show me how it increases in and show me how it increases in elevation.elevation.

1890

                                                                      

ErosionThe first five pictures of this presentation are of the same rock, just in different time periods. Pay attention to the

dates on the side of the pictures and see what the water did to this rock.

ErosionStill the same rock.

1910

                                                                    

   

ErosionErosionStill the same rock.Still the same rock.

1920

                                                              

ErosionErosionStill the same rock.Still the same rock.

1970

                                                    

ErosionErosionStill the same rock, but where did it go?Still the same rock, but where did it go?

1990

                                                                

Weathering, Erosion, and Weathering, Erosion, and DepositionDeposition

This is a picture of the same place taken This is a picture of the same place taken near the Grand Canyon near the Grand Canyon

Would maps of these look the same?Would maps of these look the same?

Here is another picture of what erosion caused.Here is another picture of what erosion caused.

Why are the roots of this tree so visible? What made this happen?Why are the roots of this tree so visible? What made this happen?

The ground has been washed away by water. That is erosion.The ground has been washed away by water. That is erosion.

Erosion can be caused by water.Erosion can be caused by water.

Erosion can be caused by wind and Erosion can be caused by wind and rain.rain.

Erosion can happen quickly or slowly over a period Erosion can happen quickly or slowly over a period of time. This formation took years and years of of time. This formation took years and years of

erosion to form.erosion to form.

These pictures are of erosion down mountains that destroyed the houses at the bottom.

So Why Do We Even Need So Why Do We Even Need Topographic Maps?Topographic Maps?

Hikers Hikers

Land PlannersLand Planners

ScientistsScientists

Topographic MapsTopographic Maps

Lesson ObjectivesLesson Objectives

Define a topographic map and state Define a topographic map and state its uses.its uses.

Describe how contour lines show the Describe how contour lines show the elevations, shape, and slope of the elevations, shape, and slope of the land.land.

Identify the meanings of some Identify the meanings of some symbols and colors used on symbols and colors used on topographic maps.topographic maps.

What is a topographic map?What is a topographic map?

A A topographic maptopographic map, also known as , also known as a contour map, is a map that shows a contour map, is a map that shows the elevation and shape of the land the elevation and shape of the land using using contour linescontour lines. .

What are contour lines?What are contour lines?

Contour lines Contour lines connect points that are of the connect points that are of the same elevationsame elevation..

They show the They show the exact elevationexact elevation, the , the shape of shape of the landthe land, and the , and the steepness of the land’s steepness of the land’s slopeslope..

Contour lines Contour lines never touch or cross.never touch or cross. Sea Level is 0 Sea Level is 0 on the mapon the map Contour line spacing depends on the land’s Contour line spacing depends on the land’s

steepnesssteepness. . Closely spaced Closely spaced lines are lines are steepsteep. . Lines Lines spread far spread far apart represent a apart represent a gentle gentle slopeslope..

Topographic Map with Contour Topographic Map with Contour LinesLines

Watch as I Make this MapWatch as I Make this Map

Now You Do It!Now You Do It!

ReliefRelief

ReliefRelief is the difference between the highest and is the difference between the highest and lowest elevation in a particular area.lowest elevation in a particular area.• Steep mountains have high reliefSteep mountains have high relief• Flat plains have low reliefFlat plains have low relief

STEEP

NOTSTEEP

Contour IntervalContour Interval

It is easier to get an idea of the area’s relief if you It is easier to get an idea of the area’s relief if you know the contour interval.know the contour interval.

Contour Interval is the difference in elevation Contour Interval is the difference in elevation between 2 contour lines.between 2 contour lines.

What do the dark colored contour What do the dark colored contour lines mean?lines mean?

The dark colored contour lines The dark colored contour lines represent every fifth contour line to represent every fifth contour line to make it easier to read the map.make it easier to read the map.

What do depressions in the map What do depressions in the map look like?look like?

A depression, such as the inside of a A depression, such as the inside of a dead volcano, is represented by dead volcano, is represented by Hachure lines.Hachure lines.

Hachure lines are regular contour Hachure lines are regular contour lines with small segments sticking lines with small segments sticking out from it.out from it.

The first hachure line is at the same The first hachure line is at the same elevation as the contour line before elevation as the contour line before it.it.

More on Contour LinesMore on Contour Lines

Contour lines form V’s that point Contour lines form V’s that point upstream when they cross a stream. upstream when they cross a stream.

It is important to remember that they It is important to remember that they point in the opposite direction as the point in the opposite direction as the flow of water.flow of water.

What do the colors on the What do the colors on the topographic map represent?topographic map represent?

Blue lines/shapes - represent water Blue lines/shapes - represent water features, such as streams and lakes.features, such as streams and lakes.

Brown – contour linesBrown – contour lines Black – Roads, buildings, railroads, Black – Roads, buildings, railroads,

other man made objects.other man made objects. Green – Woodland areasGreen – Woodland areas Red - HighwaysRed - Highways

Now that I know what a topographic Now that I know what a topographic map is, how do I read it?map is, how do I read it?

First determine the contour interval First determine the contour interval (the distance between each contour (the distance between each contour line)line)

Then determine the map scale Then determine the map scale (usually at the bottom of the map)(usually at the bottom of the map)

Identify any hills or depressionsIdentify any hills or depressions Use the legend to identify man made Use the legend to identify man made

features.features.

Reading a topographic map cont.Reading a topographic map cont.

Look for areas where the contour Look for areas where the contour lines are close together – they lines are close together – they indicate a steep area.indicate a steep area.

Look for areas where the contour Look for areas where the contour lines are spread apart – they indicate lines are spread apart – they indicate a gentle slope.a gentle slope.

Review QuestionsReview Questions

How are contour lines drawn on How are contour lines drawn on maps?maps?

How does a contour map show How does a contour map show whether a slope is gentle or steep?whether a slope is gentle or steep?

What is a benchmark?What is a benchmark? How is a benchmark shown on a How is a benchmark shown on a

map?map? How is distance measured on a How is distance measured on a

contour map?contour map?