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- Roadside Toolbox
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- Visual Impact Assessment Outlines
- VIA Training
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Policy and Process
- Rationale for Assessing Visual Impacts
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- Team Project Introduction
Visual Quality and Visual Impacts
Module 3: Visual Quality and Visual Impacts
Lesson 11: Visual Quality
Let’s start with Lesson 11—a lesson about Visual Quality.
We’re going to examine the concept of visual quality very methodically. First by defining the components that combine to form visual quality, and then we will present how the FHWA rates visual quality. We will practice defining visual quality by describing it and by assigning numerical values to it. Finally, we will consider if these rankings should be adjusted daily or seasonally.
The FHWA has defined visual quality as having three attributes: vividness, intactness, and unity. Let’s look at each one separately.
The FHWA defines vividness as the extent to which the landscape is memorable. This is associated with the distinctiveness, diversity, and contrast of visual elements. A vivid landscape makes an immediate and lasting impression on the viewer. Nature, as composed in California’s national parks can be particularly vivid. Images of Yosemite Valley are indisputably vivid—almost anyone exposed to the valley—or even just pictures of the valley—will remember it indefinitely. But it isn’t just nature that is vivid. Cultural landscapes can also be vivid. Take the example of San Francisco, a city filled with several iconic landscapes and structures. In this image of San Francisco, however, most of the buildings could be in almost any city in America. It is the distinctiveness of the TransAmerica Building that makes this image of that skyline unique and memorable.
The FHWA defines intactness as the integrity of visual order in the landscape and the extent to which the existing landscape is free from non-typical visual intrusions. Both natural and cultural landscapes can have intactness if there is little or no encroachment or degradation of what is considered typical.
The difficult part, as was noted by discussions when this course was taught as a class, is to determine what is normal. One interesting discussion was about utility lines next to rural roads. Are they an intrusion or part of a typical landscape? Interestingly, the State Historic Preservation Office, offered a way of thinking about these types of issues—they suggested that if an element is part of the landscape’s historic composition it is not an intrusion, in terms of intactness. Nonetheless, an element that does not adversely affect intactness, may still reduce vividness or unity of a composition.
The FHWA defines unity as the extent to which visual intrusions are sensitive to, and in visual harmony with, the existing landscape. Although similar to the concept of intactness, this concept allows intrusions to occur—a modern bridge in an historic district, for instance. It merely asks if the intrusion was designed or inserted sensitively into the existing landscape.
In a similar manner, if the intrusion is historically appropriate and therefore contributing to the scene’s intactness (see discussion in previous slide), it may still be insensitive to the existing landscape and may be adversely affecting unity or even vividness. This is why there are three dimensions to visual quality—so that you will know exactly why people find a particular scene attractive or unattractive.
Visual Quality Ratings
Each of the three attributes should be rated separately on a seven point scale with 0 being the lowest rating and 7 being the highest. Words can also be used for ranking.
The two images depict the range of vividness from very low to very high.
How memorable is the landscape? Begin by writing a narrative describing a landscape’s vividness or memorability, using the descriptions you generated when analyzing its visual character. What pattern element is memorable in this photograph? What type of pattern character makes them memorable?
Using a seven point scale, assign a numeric value to vividness with 0 being very low vividness and 7 being very high vividness. Some Caltrans Landscape Architects, in order to understand the vividness of the landscape more thoroughly on complex or controversial projects, will divide the landscape into landform and various land covers, assigning separate numerical values to each, and then average these values to determine a single numerical value for vividness.
Is there encroachment and degradation in this corridor? Begin by writing a narrative describing the landscape’s intactness. Imagine that this image is of a rural 2-lane highway, would a set of short pole utility lines strung along the edge of the right-of-way be out of place? Does the scale of these utility lines or that there are multiple poles and lines, seemingly needlessly redundant poles parallel to each other, create an impression of encroachment and degradation? What if the row of large poles was actually a simulation—would the existing image, with just the small poles, be more intact than the simulation?
How is it that you are forming these professional judgments in your mind? Are you relying on some of the concepts we developed when we explored the ideas behind visual character? Probably. Be sure to note the basis of your judgments.
Using a seven point scale, assign a numeric value to intactness with 0 being very low intactness and 7 being very high intactness. Some Caltrans Landscape Architects, in order to understand the intactness of the landscape more thoroughly, especially for complex or controversial projects, will divide the landscape into natural and developed (or cultural) environments, assigning separate numerical values to each, and then average these values to determine a single numerical value for intactness.
Hardly any landscape in the modern world avoids change. Change is ubiquitous, caused either by natural or human forces. When it is caused by human force, we have a choice on how well the intrusion will be integrated with existing environment—how visually coherent will the landscape be with its newly constructed elements. In the case of highways, how well will a newly constructed or reconstructed highway facility fit its surroundings?
To assess unity, intrusion is allowed. The question is, will the intrusion contribute to the existing scene, either by blending in or contrasting harmoniously. This isn’t an easy task but using the artistic analytical tools we learned when deciphering visual character can again be helpful.
Unity, like the other two attributes of visual quality, can be measured on a seven-point scale with 0 the lowest number meaning that the proposed highway is very poorly integrated into the existing scene to a rating of 7, indicating superlative integration.
Please note that changes or impacts to the visual environment, that is, adding or subtracting elements from an existing scene, is not a synonym for degradation. Sometimes unity (or vividness or intactness) can be improved more readily by removing elements than by adding new ones.
Calculating Visual Quality
Visual quality is described and calculated for each visual assessment unit at a selected key view. A narrative description of all three attributes gives a general idea of existing visual quality. Adding a numerical calculation gives more precision and allows for more exacting comparisons between “before” and “after” construction. But we’re getting ahead of ourselves.
First let’s understand how these three attributes come together to describe and measure existing visual quality. As has been stated, it can be done verbally but the FHWA process also provides a numerical method for evaluating visual quality. It simply averages the sum of the numerical ratings for vividness, intactness, and unity. It adds the values of the three attributes together and divides by three. In other words:
Adjusting Visual Quality
We tend to conduct our visual impact assessments as if it were always a nice sunny day in early summer. There are, however, changes in seasons and even changes that happen from day to night that may not be adequately described if such an approach is uniformly taken. Particularly in California, there are extended periods where a landscape that may appear lush in winter or early spring, is dry and uninviting other times of the year.
If the landscapes you are evaluating change dramatically over time, you may need to adjust your assessment to include other times of season or day to adequately assess visual impacts.
We will now apply these concepts to our team project. Using the same visual assessment unit you used to assess visual character, determine the vividness, intactness, and unity of the existing landscape.
Note that we are intentionally calling the first task of Part 5, “B” for the word “Before.” We will be completing task “A” (or “After”) later! This will make more sense when you see, on the next slide, the accompanying worksheet.
A worksheet has been created for you to record your evaluation, both narrative descriptions and numerical ratings, on a single sheet. Click on Team Project (Part 5) – Visual Impact Assessment Worksheet and print out this worksheet.
Let’s walk through how to use this template. Notice that the template has three primary columns and three primary rows. Each column is a step in the process that determines visual quality. The columns are placed to facilitate the mathematics of the process with the “After” column first; the “Before” column second; and the “Change” column last. This order allows the “Before” column to be easily subtracted from the “After” column, resulting in an answer placed in the “Change” column to correctly reflect a positive or negative change to the existing scene. Coincidentally, the column headings are also in alphabetical order—After, Before, Change—or A-B-C—to help you remember the order.
There are three primary rows in the worksheet—one for each attribute that together compose visual quality. The first row is for vividness; the second for intactness; and the third is for unity. Notice that each row has space to write brief descriptive narratives and record numerical ratings for each stage of the process.
Begin by filling in the number of the key view you will be investigating in the highlighted blue box in the upper left corner of the worksheet.
The descriptive analysis of visual quality should be written in the blue boxes as shown on this slide. Use the notes you made earlier for your analysis of the Visual Character to help you compose these descriptions.
Similarly record the numeric value you assign to vividness, intactness, and unity in these blue boxes.
For the numerical ratings, once you have completed filling in all the boxes that have been highlighted in blue, add up the three blue boxes in each of the columns separately and then record the sum in the corresponding red box.
Divide the red number in each column by three. Put that number in the dark blue box as shown in the slide. For quality assurance, verify that the number for “Change” is correct by checking it both by column and by row.
You now have three numerical ratings for visual quality—”After,” “Before,” and “Change”—to add to your verbal descriptions.
Describing and Rating Visual Quality
Let’s start the process of determining changes to visual quality with the middle or “Before” column.
Example of a Key View
Assemble and review all the information you have gathered about your visual assessment unit as seen from its key view, including the project map, narrative, and photographs. Pick one of the photographs that approximates your key view the best. (The above photograph is for illustrative purposes only—your key view may be different.) Also include your analysis of visual character.
Using these assets, fill in the middle column of the worksheet one box at a time. Determine vividness first, writing a brief descriptive narrative and then determine the numerical rating. Follow this by filling in the boxes for intactness, then unity.
Using only bullet points for the narrative is not only fine, sometimes it is preferred as way to get to the crux of the matter and makes comparing the “Before” and “After” statements easier.
Module 3 Part A Completion
We have begun to gather the information we need to assess visual impacts. We now know what the visual character and visual quality is of the existing scene (at least at one key view). We will complete the process in Lesson 12.