Earth Science CK-12 2.4 Topographic Maps

Principles that are important for reading a topographic map: 5. What are three common scales used in USGS maps?

(1) 1:24,000 scale -1 inch = 2000 ft (2) 1:100,000 scale -1 inch = 1.6 miles (3) 1:250,000 scale -1 inch = 4 miles

What are the two steps you would do to calculate the contour interval in a contour map?

1. Calculate the difference in elevation between two bold lines 2. Divide that difference by the number of contour lines between them

Principles that are important for reading a topographic map: 4. Where water flow is light or nonexistent, there is no longer what?

A blue line

Mathematically, a contour line is a curve in two dimensions on which the value of a function f(x,y) is a what?

A constant

Principles that are important for reading a topographic map: 3. Hatched concentric circles indicate what?

A depression

Principles that are important for reading a topographic map: 2. Concentric circles indicate what?

A hill

Principles that are important for reading a topographic map: 2. When contour lines form closed loops all together in the same area, this would be what?

A hill

On a topographic map, contour lines create a group of concentric, closed loops. What feature could this indicate?

A hilltop

Principles that are important for reading a topographic map: 2. Broadly spaced contour lines indicate what?

A shallow slope

Principles that are important for reading a topographic map: 1. Contour lines that seem to indicate what?

A very steep slope, like a cliff or canyon wall

In a contour map, each contour line represents a specific elevation and connects all the points that are at where?

At the same elevation

A topographic map with the contour lines representing deph below sea level, rather than height above

Barthymetric maps

Principles that are important for reading a topographic map: 1. Closely-spaced contour lines indicate a steep slope, why?

Because the elevation changes quickly in a small area

Principles that are important for reading a topographic map: 4. If a stream contains water, the contour line will be

Blue

In a contour map, every fifth contour line is what?

Bolded and labeled with numerical elevations

In a contour map, a single point can only have what?

Can only have one elevation

Topographic maps use what to show different elevations on a map?

Contour lines

Type of isoline; in relation topographic maps, a line of equal elevation

Contour lines

Mapping is a crucial part of what?

Earth science

A map that shows the geological features of a region

Geologic map

Principles that are important for reading a topographic map: 3. Outer hatched circles of hatched concentric circles represent what?

Higher elevations

Principles that are important for reading a topographic map: 5. Scales on topographic maps indicate what?

Horizontal distance

On a topographic map, five contours lines are very close together in one area . The contour interval is 100 ft. What feature does that indicate? How high is this feature?

If the contour interval is 100 ft that means that there is 100 ft in between each line so that would mean it would be very steep and it would be 400 ft high.

On a topographic map, six contour lines span a horizontial map distance of 0.5 inches. The horizontal scale is 1 inch equals 2,000 ft. How far apart are the first and sixth lines?

If the distance between the first and sixth line is 0.5 inches which equals 1,000 feet and 1 inch is equal to 2,000 feet and there are six lines then there is 1,000 feet inbetween the first and sixth line.

In a contour map, two contour lines next to one another are separated by a constant difference in what?

In elevation

Bathymetric maps help oceanographers visualize what?

Landforms at the bottoms of lake, bays, and the ocean as if the water were removed

In a contour map, the contour lines run next to each other and NEVER what?

Never cross

In bathymetric maps, number are what and become what?

Numbers are low near sea level and become higher with depth

Principles that are important for reading a topographic map: 1. Contour lines show the 3D shape of what?

Of the land

On a geologic map of the Grand Canyon, a rock unit called the Kaibab Limestone takes up the entire surface of the region . Down some steep topographic lines is a very thin rock called the Toroweap Formation and down more topographic lines into the canyon from what that is another thin unit, the Coconino Sandstone. Describe how these three rock units sit relative to each other. Which is oldest and which is youngest?

On the top is the Kaibab limestone, next is the Toroweap Formation, and after that is Coconino sandstone. The oldest is the Coconino sandstone and the youngest is the Kaibab limestone.

What two things are shown in geologic maps?

Rock units and geologic structures

In a geologic map, rock units are what?

Rock units are color-coded and identified in a key

Principles that are important for reading a topographic map: 3. Hatch marks of hatched concentric circles are what inside a circle?

Short perpendicular lines

Principles that are important for reading a topographic map: 4. V-shaped expanses of contour lines indicate what?

Stream valleys

In a geologic map, structural features such as what are shown?

Structural features such as folds and faults

With contour lines to indicate elevation, topographic maps show what?

Terrain

Principles that are important for reading a topographic map: 4. Where water flow is light or nonexistent, there will no longer be a blue line, but contour lines that point uphill indicate what?

That the stream channel is still there

In a contour map, what does the map legend give?

The countour interval

The constant difference in elevation that seperates two contour lines next to one another in a contour map

The countour interval

Principles that are important for reading a topographic map: 3. Innermost hatched circle of hatched concentric circles would represent what?

The deepest part of a depression

Principles that are important for reading a topographic map: 4. If a stream contains water, and the contour line is not blue, the V patterns indicate what?

The direction water will flow

Principles that are important for reading a topographic map: 4. The channel of a stream passes through a point of the V and the open end of the V represents the what?

The downstream portion

Principles that are important for reading a topographic map: 2. The smallest loops of contour lines are what?

The higher elevations of a hill (uphill)

Contour lines connect all the points on a map that have the same elevation and therefore reveals what?

The location of hills, mountains, and valleys

Principles that are important for reading a topographic map: 2. The larger loops of contour lines are what?

The lower elevations of a hill (downhill)

On a topographic map, a river is shown from Point A in the northwest to Point B in the southeast. Point A is on a contour line of 800 ft and Point B is on a contour line of 900 ft. In which direction does the river flow?

The river flows toward point A, so northwest.

Principles that are important for reading a topographic map: 5. The horizontal scale on topographic maps can be used to calculate what?

The slope of the land (vertical height/horizontal distance)

Describe the pattern on a topographic map that would indicate a stream valley. How do you determine the direction of water flow?

There would be a striaight line with some Vs going through it, the lines that extend the Vs outward show that the river is going in the same direction.

Maps are extremely useful to Earth scienctists to represent and show what?

To represent geographic features found above and below sea level and to show the geology of a region

Represents the location of geological features, such as hills and valleys

Topographic maps

Principles that are important for reading a topographic map: 4. Where a stream crosses the land, the Vs in the contour lines point where?

Uphill

If you walk along a contour line you will not go where?

Uphill or downhill

On a topographic map, describe how you can tell a steep slope from a shallow slope.

When it is a steep slope the lines are very close together, when the lines are father away from each other it is a shallow slope.

While a road map shows where a road goes, a topographic shows what?

Why