- Index lines are the thickest contour lines and are usually labeled with a number at one point along the line. ...
- Intermediate lines are the thinner, more common, lines between the index lines. ...
- Supplementary lines appear as dotted lines, indicating flatter terrain.
What are the 4 rules for reading a contour map?
Rule 1 – every point of a contour line has the same elevation. Rule 2 – contour lines separate uphill from downhill. Rule 3 – contour lines do not touch or cross each other except at a cliff. Rule 4 – every 5th contour line is darker in color.
How do you read a contour number?
Remember contour numbering reads up hill – in other words the top of the number is uphill and the bottom is downhill . Also remember the closer contour lines are together, the steeper the slope.
What do the numbers on a contour map mean?
Contour elevation numbers indicate the direction of elevation by always reading (pointing) uphill . What is scale? Maps are made to scale. In each case, the scale represents the ratio of a distance on the map to the actual distance on the ground.
How do you read depression contour lines?
How do you read elevation contour lines?
You can figure out the elevation of any point by finding the nearest labeled line, counting the number of lines above or below it, multiplying by the contour interval, and adding or subtracting the result from the nearest marked contour line . The more closely spaced the contour lines, the steeper the slope.
How do you do contour mapping?
- Gather supplies. ...
- Draw orientation lines on the drawing paper. ...
- Make a clay mountain and cut layers out of the mountains. ...
- Use the clay layers to draw contour lines. ...
- Complete your contour maps with DOGSTAILS. ...
- Share your contour map and explore contour maps of your local area.
What are the 5 Rules of topographic maps?
- Contour Lines Never Cross. ...
- Measuring Steepness. ...
- Stream Flow Direction. ...
- Contours Close. ...
- Concentric Circles. ...
- Elevation Between Lines.
How do contours work?
Contour lines connect points that share the same elevation : Where they’re close together (they never intersect), elevation is changing rapidly in short distance and the terrain is steep. Where contour lines are wide apart, elevation is changing slowly, indicating a gentle slope.
What do topographic maps show?
Contours make it possible to show the height and shape of mountains, the depths of the ocean bottom, and the steepness of slopes . USGS topographic maps also show many other kinds of geographic features including roads, railroads, rivers, streams, lakes, boundaries, place or feature names, mountains, and much more.
What are the six rules for reading a topographic map?
- Rule 1: Slope. The closer the lines are, the steeper the slope. ...
- Rule 2: Flow and Source of a River/Stream. ...
- Rule 3: Mountains and Hills. ...
- Rule 4: Highest possible elevation of a hill/mountain. ...
- Rule 5: Depressions. ...
- Rule 6: Lowest possible elevation of a depression.
How do you read latitude and longitude on a topographic map?
What do V shaped contour lines indicate?
The “V” shape contours indicate streams and drainage . As you can see, the “V” points uphill to a higher elevation. Generally, you can connect the apexes of the upward-pointing, “V” shaped contour lines to delineate a stream.
What does a depression look like on a map?
A depression is represented by a series of concentric closed contours with the inner contours having lower elevation than their outer surrounding . There are small tick marks or hachures on these contour lines pointing towards lower elevation.
Where are contour maps useful?
Contour maps help us to understand the characteristics of the landforms. These maps are of immense use to mountaineers, trekkers, soldiers, defense officers , etc. These maps prove to be of great use in the planning for a region too.
Do contour lines merge?
Two or more contour lines merging indicates a cliff . By counting the number of contours that cross a segment of a stream, the stream gradient can be approximated.
