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A topographic map is used to show topography and features using symbols.

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Presentation on theme: "A topographic map is used to show topography and features using symbols."— Presentation transcript:

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2 A topographic map is used to show topography and features using symbols.

3 Green- vegetation Blue- water Brown- natural features Black/red- man made features http://pubs.usgs.gov/gip/TopographicMapSymbols/topomapsymbols.pdf

4 Contour lines- indicate elevation using lines and associated numbers

5 Forests and Clearings- shaded green Streams- shown in blue Trails- single dashed lines Roads- red double lines (dashed for dirt, thicker for major roads)

6 Buildings: Solid- inhabited (house) Hollow- uninhabited (barn) Multiple buildings may be shaded pink

7 Boundaries: Broken lines, shape depends on type. Benchmarks: indicate survey, uses triangles or X and BM with elevation measurements.

8 Contour Lines Each line connects points of equal elevation Measured in terms of elevation above or below sea level Can be based on other elevations Illustrates shape of land surface on a map Can indicate which way water flows (from higher elevations to lower elevations)

9 Elevations are evenly spaced vertically for ease of reading Spacing depends on topography High relief (mountains) have larger intervals so not too crowded to read easily Intervals are noted in margin of map Every 5 th line is marked darker as an Index contour and are usually labeled. (usually wider as well)

10 You can determine contour interval by dividing elevation difference of index contours by 5. Units of elevation are marked in the margin. Most US maps use feet, but some do use meters.

11 Drawn so that distance on map are proportional to distance on ground. Scale provides the proportions used Verbal Scales state what distance on map equals specific distance on ground (ex: 1 inch = 2000 feet)

12 Fractional scales do not provide units, provide the ratio of map distance to the equivalent distance on the ground Written as fractions (1/62,000) or ratios (1:62,000) Can use any units and be turned into a verbal scale.

13 Bar scales are lines drawn to a known ground length Provide distance marks for visual estimation Can be sued like a ruler to measure the distance Be careful where zero point is located when using the bar scale.


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