Slope = "rise over run", or vertical height increase over horizontal distance. Measure the distance between the contour lines (at right angles to the lines themselves). ğind the point at which you want to know the slope. (as this is an estimate only, don't suggest you know it to within 0.5 m round to the nearest 10 m, and call it 260 m). Ğxample: if a point is 1/4 of the way between the 250 m and 300 m contours, we estimate its height as 250 plus 1/4 of the contour interval (in this case 50 m). Ğstimate height of the point between those elevations. ğind the elevations of the contour lines on each side of it. ğind the point you want to know the height of. Note: not all contour maps are of elevations! This link (PDF file) which includes a section about contour maps.Ībout interpreting contour maps. Shaded relief: shows hills and valleys as if illuminated by sun. Ĝontours: A contour is a line joining points with the same elevation. Steeper slope, thicker hachures, so steep slopes look darker. Hachuring: slopes shown by many small lines pointing downhill. earliest method: pictures of hills (since 2000 B.C.) Ğlevations relative to geoid measured by surveying.Ĭheck out this link for more information: All heights are measured from this DATUM. It differs from the spheroid (flattened sphere) by 80 to 100 m maximum. This global shape of the sea surface is called the GEOID. Ğstimated under the land (imaginary water level in a canal crossing the land from coast to coast). Use SEA LEVEL (mean sea level, or high water mark on a coast, etc.). Need a DATUM (reference level) to refer to. If you have time, use Nat Geo's TOPO! Explorer to find and analyze topographic maps of your local area.Elevation, slope, contours Elevation 1. Share your contour map with a friend or family member and challenge them to read it. Share your contour map and explore contour maps of your local area. Sources: who provided information for the mapĦ. Index: the part of the grid where specific information can be located Orientation: direction (north arrow or compass rose) Finally, add any missing DOGSTAILS information: Hint: Use any color but blue, because blue represents water on contour maps. Color each layer-the space between each contour line-a different color, and create a map key to show what elevations each color represents. Label the base of the mountain on the contour map with 0 feet and write in elevations for the other levels, using an elevation range of 100 feet per line. The base of your mountain is at sea level, or 0 feet of elevation. Complete your contour maps with DOGSTAILS. You are drawing contour lines for a topographic map.ĥ. Outline this layer and repeat the process with the top two layers. Then remove the bottom layer of clay and place the next largest layer of clay within the first outline. Place the bottom layer of clay on the second piece of drawing paper and outline it. Re-draw orientation lines on the second sheet of drawing paper. Use the clay layers to draw contour lines. When you finish, you should have four separate layers.Ĥ. Now hold the fishing line very tight and use it to slice all the way through the clay along the rings. Mark the third ring three-quarters of the way down from the peak. Mark the second ring halfway down from the peak. Mark the first ring a quarter of the way down from the peak. Use a pencil to mark three rings in your clay mountain to indicate different elevations. Line up the dot with the intersection of the two lines, and draw the lines across the clay mountain so it is clearly divided into the four quadrants. Shape your clay into a mountain on the drawing paper and mark its peak with a dot. Make a clay mountain and cut layers out of the mountains. The peak of the mountain will line up with the intersection, so that your mountain looks like it is divided by a grid.ģ. First, draw a straight vertical line and then a straight horizontal line intersecting it to create four equal sections. Draw orientation lines on the drawing paper.ĭraw orientation lines on the drawing paper. Then gather the following supplies: two sheets of drawing paper, a ball of clay, markers of different colors, several feet of fishing line, and a pencil.Ģ. The closer the lines, the steeper the elevation. First, look closely at the map images of contour maps. You are going to make your own contour map with DOGSTAILS.
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