| It is relatively easy to read elevation data, as long as | | | | equal elevation to each other. They are essential to |
| you become familiar with a few of the key terms and | | | | understanding elevation data. They show bands of |
| rules. When looking at elevation on a topographic map, | | | | elevation, as well as spot elevation on a map. |
| it can be quite confusing. With all the various | | | | - Hachures: Hachures are marks pointing downwards |
| professionals using elevation data in their vocations, it | | | | and are found on contour lines. These marks indicate a |
| has been made much more comprehensive. To give | | | | depression in elevation. These depressions can be the |
| you an idea of how important gathering and | | | | result of erosion, meteor craters, or just naturally |
| understanding elevation data is, here is a list of a few | | | | occurring dips in elevation. |
| uses. | | | | Finally, here are a few important rules to remember |
| - Highway construction | | | | when dealing with an elevation map. |
| - Education for grade school children | | | | - The first rule is sometimes called the rule of V’s. |
| - Risk assessment for environmental hazards (floods, | | | | They are usually found in stream valleys, with drainage |
| wildfires, mudslides, earthquakes) | | | | channels passing through the point where the hachure |
| - Water supply, treatment, and drainage routes | | | | is located. |
| - Planning Marathons and Triathlons | | | | - Another is often referred to as the rule of O’s. |
| Here are a few key terms to be familiar with in order | | | | The O’s are closed loops that have higher |
| to understand what you are seeing when you look at | | | | elevations on the inside and head downhill on the |
| a topographical map. | | | | outside. If the closed loops are craters or depressions, |
| - Elevation: In terms of land, this refers to the distance | | | | they are indicated by hachures. |
| in relation to sea level. Where the ocean meets dry | | | | - The third is the spacing of contours. If the contour |
| land is sea level; it is normally measured in feet. | | | | lines are close together, this indicates a steep hill, and if |
| - Contour lines: These invisible lines connect points of | | | | they are far apart, it indicates a gentle slope. |