# ISOLINES 1 Isolines NEVER touch or cross each

• Slides: 49

ISOLINES 1. ) Isolines NEVER touch or cross each other. 2. ) Isolines have gentle curves. 3. ) The points along an isoline are all the same value. 4. ) Isolines never end, except at the edge of a map. 5. ) The change in value from one isoline to the next is always the same. 6. ) Isolines tend to make parallel curves. 7. ) Isolines have values that are higher and lower on both sides of them.

Constructing and Interpreting a Field Map http: //www. stadiumsofnfl. com/afc/Giants. Stadium. htm

Models and Dimensions of Earth - 14 V. Fields - Any region of space or the environment that has some measurable value of a given quality at every point A. Isolines- Lines that connect points of equal field values

1. What is the approximate elevation of points A, B, and C? A. 75 feet B. 45 feet C. 55 feet 2. Isolines that show elevation are called Contour Lines

1. What measurable property is shown on this map? TEMPERATURE °C 2. Based on this property, the isolines on this map are called ISOTHERMS 3. What is the approximate measurement of this property for New York State? 5°C

1. Approximately how many thunderstorms occur each year in: a. Albany, New York - ~ 25 thunderstorms b. Los Angeles, California- ~ 5 thunderstorms c. New Orleans, Loisiana - ~ 75 thunderstorms

ISOLINES 1. Do isolines ever touch or cross each other? NO 2. Do isolines usually have sharp angles or gentle curves? (Please pick one. ) Gentle Curves 3. What does each point on an isoline have in common with all other on the same line? They all have the same value 4. Do isolines ever end, except on the edge of the map? NO

ISOLINES 5. Is the change in value from one isoline to the next always the same on a single map? YES 6. Do isolines tend to make parallel curves? YES 7. Does every isoline have one side where the values are higher and another side where the values are lower? YES

Difference in elevation between the high and low points of a land surface

Directions: Use a Pencil to draw the snowfall line on map 1 every 20 inches. Be sure to extend your isolines to the edge of the map if necessary.

Directions: Use a Pencil to draw contour lines every 10 feet. Be sure to extend your isolines to the edge of the map if necessary.

VI. Topographic Maps … are maps of an elevation field A. Topographic Maps show the elevation of the land by using contour lines, and show other natural and man-made features using symbols. B. Contour Line- Isolines that connect elevation above and below sea level. Elevation - The vertical distance or height above sea level. C. Contour Interval- The difference in elevation between two consecutive contour lines. D. Index Contour Line- Darker contour lines marked with elevations

Topographic Map- Showing Contour Lines What is the Contour Interval?

E. Depression Contour Line- Special contour line used to show a hole or crater on Earth’s surface. These lines are drawn like contour lines but are marked on the inside. * The first depression contour line has the same value as the last regular contour line. Each smaller and smaller depression contour line is one contour interval less than the previous line.

F. Bench Mark (B. M, )- A metal marker in the ground labeled with an exact elevation for a location.

Spot Elevations- are the elevations of such places as road intersections, hilltops, lake surfaces and other points of special interest. These points are located on the map by a small cross (+), unless the location is obvious, such as certain road intersections or hilltops.

80 feet 140 feet 100 feet

4. Contour Interval- 20 feet 5. Highest possible elevation (of the hilltop)6. Which is the steepest side of the hill? 259 feet East

7. How do contour lines show a steeper slope? Closely spaced contour lines show a steeper slope

8. What three (3) basic features of a landform do contour lines show? a. Hills- shown by closed concentric circles of contour lines.

b. Cliffs- shown on a topographic map, where contour lines are spaced very close together.

c. Depressions- marked with small lines pointing toward the center of a depression.

I. River Valleys (the law of V’s) – contour lines bend upstream where they cross a river. This can be used to determine the direction in which the river is flowing.

The direction of a river can be found on a topographic map two ways: 1. Contour lines bend upstream- All rivers flow downstream. 2. Look at the elevation the river flows through. Rivers flow downhill or from High elevation to a Low elevation.

Base your answer to this question on the topographic map below. Points X, Y, and Z are locations on the map. Elevations are expressed in meters. Mill River generally flows toward the North East There a couple of different ways to tell which direction Mill River flows. They are: - smaller bodies of water flow into larger bodies of water - the contour arrows point in the opposite direction the stream in flowing - higher to lower elevation Using all or one of these one can tell the stream is flowing in a NE direction.

J. Common Symbols on Topographic Map 1. Building 2. 3. 4. 5. Swamp or Marsh 6. Railroad Church School 7. Cemetery 8. Mine

VII. Map Reading Skills 1. Dublin is West 2. Manchester is of Manchester. East of Dublin. 3. Southampton is Southeast of Dublin. 4. Belfast is Northwest 5. Glasgow is of London. North of Cardiff. 6. Limerick is Southwest of Aberdeen. 7. Aberdeen is Northeast of Limerick. 8. Manchester is South of Newcastle.

80 feet 100 feet 120 feet 60 feet 80 feet 100 feet 40 feet 20 feet 60 feet 20 feet 40 feet

. . 100 . . 120 80 60 40 . . . . 20 A A’

Gradient – (SLOPE) a measure of how steep the land is. Formula: Gradient = Change in Field Value Distance

Base your answer to this question on the topographic map below. Points X, Y, and Z are locations on the map. Elevations are expressed in meters. What is the elevation of point Z? 220 meters Using the contour interval located at the bottom of the map (20 meters) one can find the elevation of point Z. Since the contour line that surrounds Z is 200 m and Z is one line up from 200 the answer would match with 220 m.

The numbers on the map represent the concentration of gasoline found at that location. What is the name of the line that we would connect equal values on this map?

What is the Isoline Interval of this field map?

What does the closely spaced contour lines indicate?

Which way do Contour Lines bend as they cross a River?

What do the hatcher lines on the inside of a contour loop indicate?

Given the topographic map above, which of the four choices below accurately depicts the correct profile between points X and Y?

The best way to approach this is by the process of elimination. First of all, point X appears to be approximately 310 meters in elevation. Let's eliminate all the choices that don't begin at 310 meters: That eliminates choices 1 & 3 right off the bat! X X

Next, we look at point Y, which appears to be approximately 130 meters. That eliminates choice 4. That means choice 2 must be correct!

Making a Topographic Profile

Next, transfer the points from the contour map to the grid.

Then connect the points with a smooth line to draw the profile.

And there! We have a cross section of the landscape.