As a Travel Photographer, I often find myself capturing stunning landscapes and natural wonders. One of the most fascinating aspects of these locations is the varied topography, which can include everything from gentle slopes to steep inclines. Topographic maps provide valuable information about the elevation and terrain of a particular area, allowing me to better understand the landscape before capturing it through my lens.
When studying a topographic map, one key feature that stands out is the representation of steep slopes. On these maps, the contour lines are closer together when the slope is steep. The distance between these lines represents the distance until the next significant incline. Therefore, when the contour lines are closer together, it indicates multiple inclines in close proximity, forming a steeper slope. Conversely, if the contour lines are further apart, it suggests a more gradual incline.
To visualize what a steep slope looks like on a map, one must observe the spacing of the contour lines. Widely separated contour lines indicate a gentle slope, while contour lines that are very close together indicate a steep slope. In fact, the peak of a steep slope is typically considered to be located at the halfway point between two closely spaced contour lines.
But how do we define a steep slope? According to legal definitions, steep slopes are hillsides that have a vertical rise of 15 feet or more over a horizontal run of 100 feet, or a slope of at least 15%. These areas can be challenging for development due to the difficulty of building on such steep grades. Therefore, it is crucial to accurately identify and understand these slopes when planning any construction or development projects.
As for classifying slopes based on their degree of steepness, a slope between 30° and 40° can be defined as ‘steep’, while slopes above 40° are termed ‘very steep’. However, it is worth noting that the term ‘extreme’ is often misused and overused when describing slopes.
Now let’s address some frequently asked questions about steep slopes on topographic maps:
1. Is a 20% slope steep?
A slope between 11% and 20% is considered moderate, but gradients above 20% are considered “steep”.
2. How can you tell a steep slope from a shallow slope on a topographic map?
Closely-spaced contour lines indicate a steep slope, as the elevation changes quickly in a small area. On the other hand, broadly spaced contour lines indicate a shallow slope.
3. Where is the steepest point on a topographic map?
To locate the steepest slope on a topographic map, look for contour lines that are closely spaced. The closer they are to each other, the steeper the slope. You can even calculate the slope by determining the vertical distance between the contour lines and the horizontal distance between them.
4. What is slope topography?
Slope and topography describe the shape and relief of the land. Topography refers to the measurement of elevation, while slope represents the percent change in elevation over a certain distance. Topographic contours, which connect points representing the same elevation, are used to measure topography.
5. How do you know if a slope is steep or not?
Steeper lines on a topographic map have a larger slope value (m > 1), while flatter lines have an m value between 0 and 1 (often in fractional form). The numerator represents the vertical distance, and the denominator represents the horizontal distance.
6. Is a 10% hill steep?
A 10% grade indicates a rise of 1 unit of vertical in 10 units of horizontal. While it may not be considered extremely steep, it is still quite challenging for activities like cycling.
7. How steep is a 45-degree hill?
A 45-degree slope is equivalent to a 100% grade, where the run descends one vertical foot for each horizontal foot. In comparison, a very steep highway-pass road is approximately 7% or about 4 degrees.
8. What does a 6% gradient look like?
A 6% grade means that over a 100-unit distance, the road will rise 6 units. The profile of a road with a 6% grade would resemble a right triangle, with a gradual but noticeable incline.
Understanding the topography and features of a landscape, including steep slopes, is essential for travel photographers like myself. It allows us to plan our shots accordingly and capture the unique beauty that these terrains offer. So, next time you come across a topographic map, take a moment to appreciate the wealth of information it provides about the steep slopes that shape our natural world.
