It is a type of imaginary contour lines on a map of chart that connects all the points having same depth below water surface like ocean, sea and lake. There are two types of scales on the topographic map. A contour line is an imaginary outline of the terrain obtained by joining its points of equal elevation. Contour lines with vshaped with convexity towards higher ground indicate valley fig. As with all types of isolines, when contour lines are close together, they represent a steep slope, whereas when lines are far from each other, they represent a gradual slope.
Properties of contour maps in the previous section two types of surface were mentioned. Draw a line between the two points bounding the desired profile area. If the map pplementary contour lines, do not contour intervals printed below the bar scales in the middle of each map is the contour interval. A contour line may never intersect other contour lines. Thus, contour lines on a plan illustrates the topography of the area.
The lines that connect points having the same elevation are a kind of isopleth called contour lines, or contours. Contour lines software free download contour lines top. Such a line gives the contour or shape of the melodic line. Redbrown the colors red and brown are combined to identify cultural features, all relief features, nonsurveyed spot elevations, and elevation, such as contour lines on redlight readable maps. They never cross, split or intersect at a cliff they might merge. For example, a 600 six hundred foot contour line on a map means that every point on that contour line is 600 above sea. Outline of the object and interior parts of the object, really just the basics showing the object without any shading. There are 3 kinds of contour lines youll see on a map. Contour lines contour lines connect places of equal altitude contour lines depict various landforms on a map by reading the contour lines we can determine what the terrain in an area looks like. The ability to fuse these major factors is the most critical skill one can learn when using a topographic map. Suppose a map includes contour lines of 100m, 98m,96 m and so on. Divide 300 feet by 3 to get one contour every 100 feet. The three types of contour lines used on a standard topographic map are.
A third type of contour line that is not often used is the supplementary contour line. This contour drawing gives an indication of general physical features. All points on the contour line are at the same elevation. Isolines, also referred to as contour lines, can be used to represent elevation on a map by connecting points of equal elevation, for instance. They may use the same sheet of paper to create these drawings. It is a type of contour lines on a map of chart with connects the point of equal temperature of a given area. A map with contour lines on it is called a topographic map. The drawing utensil stays in uninterrupted contact with the face of the paper during the entire length of the drawing. Topographic maps use a combination of colors, shading and contour lines to represent changes in elevation and terrain shape.
Imaginary line joining points of equal elevation above or below a datum contour lines have a specific contour interval interval is the vertical distance between contours ci is a. Concentric circles of contour lines indicate a hilltop or mountain peak. When contour lines are far apart, the slope of the hill is gentlesteep. Vary the width of the contour line to give emphasis and weight to the line. Then, it traces the next contour using the previous pixels type. These imaginary lines provide a good visual representation of the terrain. Index index contour lines are accented with a heavier mark, so that these lines will be the first thing to catch your eye when you look at a topographical map. This worksheet packet starts with a sheet that takes students through the basic supplies needed to begin drawing. Starting at zero elevation, or mean sea level, every fifth contour line is always an index contour line, regardless of the contour interval. In art, lines may be the path made by a pencil or the stroke of a paintbrush. A contour line must represent one and only one elevation.
A contour line may also be defined as the intersection of a level surface with the surface of the earth. You can often get a good idea of the shape of this line by looking at the melody as it is written on the staff, but you can also hear it as you listen to the music. A contour is a line drawn on a map that joins points of equal height above sea level. Mapmakers show index contour lines as a heavily drawn line with. Index lines are the thickest contour lines and are usually labeled. A beginners guide to understanding map contour lines os. A feature shown on a ma p by the contour lines becoming v. Pu 09,10,14 contour interval ci it is the vertical distance between any two consecutive contours. In cartography, contour lines are imaginary lines of a terrain that joins point of equal elevation above a given level, such as mean sea level or benchmark.
Using the contour lines on a map, the elevation of any point may be determined by. Contour lines types, characteristics and uses in surveying. This line is depicted as a dashed line and is used to indicate an minimal change in elevation or terrain between two intermediate contour lines. A detailed guide to contour lines, formations, drawings, hills and depressions. Like all contour lines, they form in concentric circles or shapes and each index contou. Contour lines contour lines describe the shape of an object, and include interior detail. Both types of maps show roads, water features, cities and parks. Representing heights on maps professor keith clarke contours on maps.
The most distinguishing feature of contour farming is the contour line. Online army study guide land navigation map reading. Draw perpendiculars from ab line, intersecting contour lines, to the corresponding line at the crosssection base. Use contour lines to determine elevations of mountains and flat. It is an imaginary line perpendicular to the slope of a farm and is equivalent to the row in checkrow pattern of planting. Specific names are most common in meteorology, where multiple maps with different variables may be viewed simultaneously. For contour following, the rundatabased following method constructs a runfollowing relationship between the edge points of two adjacent scan lines. If contour lines are meeting in some portion, it shows existence of a vertical cliff fig. It is a type of contour lines on a map which connect the point of equal salinity in the water body majorly contour. Topographic maps also represent streets and trails, vegetation.
Topographic maps show a universal transverse mercator utm grid, allowing the user to. A single contour line can not lie between two lines of higher or lower elevation. Essentially, topographic maps represent the threedimensional landscape of earth within the twodimensional space of a map. Land features are identified from the contour lines. Regression methodology for bivariate heteroscedastic data pdf. For example, a contour drawing of a persons face would include a line defining the shape of the head and additional lines that describe the surfaces and planes of the facial features. You would draw lines that would follow along the form.
How to read and understand topographical maps for trails and hiking while backpacking or in a survival situation. Think of an ant crawling across the object or a topographic map. As with all isolines, when contour lines lie close together, they represent a steep slope. Smoothly join all the points marked on different lines at the crosssection base. Rule 5 contour lines are closer together in steep terrain and farther apart in flat.
Look for the height and shape of the ground which is shown on 1. It is possible to describe the form of either type on a map. Therefore, it can classify the type of contour pixels as a straight line, inner corner, outer corner and innerouter corner, and it can extract pixels of a speci. The 10 different insects provide students with an opportunity to practice identifying contour lines and applying value throughboth blending and crosshatching techniques. Every fifth or tenth contour starting at sea level is an index contour, which is drawn as a heavier line and is labelled. They show sudden changes in elevation of at least onehalf the contour interval for that map. A contour line must never simply end, except at the edge of the map. Fast contourtracing algorithm based on a pixelfollowing. The closer that the lines are on the map the steeper the terrain is. This contour line extends the length of the filled area and has tick marks that point toward lower ground. A contour line connects points of equal height above sea level, called elevation. The three types of contour lines figure 101 used on a standard topographic map are as follows.
Different types of isolines in geography thoughtco. By reading the contour lines an understanding of the shape of the land is obtained. Contour lines are often given specific names beginning iso ancient greek. Contour line, a line on a map representing an imaginary line on the land surface, all points of which are at the same elevation above a datum plane, usually mean sea level. The continuous line drawing is unbroken from beginning to end. The line or row traverses the farm from one boundary to the opposite across the slope regardless of the aspect of. Imagine a land surface inundated by the sea to a depth of 100 feet 30. Contour lines mark points of equal elevation on a map and are critical to. Mark four points two on the endpoints, and two between and draw the contours. Topographic maps show contours, elevation, forest cover, marsh, pipelines, power. Chapter 2 reading topographic maps and making calculations.
It is a type of contour lines on a map of chart with connects the point of. The land between k and l would be higher than 250 ft because closed contour lines without hatch marks indicate high points. This standard was prepared to define the accepted drawing types used to establish engineering requirements. On a topographic map, what are the three types of contour. Topographic maps the light brown lines on the topographic map are called contour lines. A contour line of a function of two variables is a curve along which the function has a constant. Now use the contour line drawing method to create an outline drawing of the stilllife on another sheet of 18x 24 paper. If the contour interval is not printed on the map, it can be calculated which is discussed later in this chapter. On line h the contour lines bend toward hurricane creek. Contour lines generally do not meet or intersect each other.
Topographic map symbols usgs publications warehouse. The elevation represented by contour lines is the vertical distance above or below sea level. When contour lines are close together, the slope of the hill is gentle steep. Contour interval is the difference in elevation between two adjacent contour lines. From each mark, indicate the vertical height with a dot on a scale. Contour lines software free download contour lines top 4 download offers free software downloads for windows, mac, ios and android computers and mobile devices. The contour lines are depression contours, closed contours with hatch marks. Continuousin this type of line study, the pencil will never leave the page. When successive contour lines are close together, this is a gentlesteep slope or hill. Blue identifies hydrography or water features such as lakes, swamps, rivers, and drainage. The artists eye may go back and forth between object and drawing. There are several types of contour line drawings, the most used and famous are the following ones.
Line types many types of lines are used to create art. What are the different types of contour lines on a map. Introduction from the hydrographic point of view a topographic survey consists of a series of tasks carried out with the aim of determining the composition of those parts of the earths surface which emerge from the water. A contour line represents an imaginary line on the ground, above or below sea level. If the map scale permits, the length of the fill tick marks are drawn to scale and extend from the base line of the fill symbol.
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