PA - Site Planning and Design - 3 - Site Data and Analysis

Site Analysis Purpose and Importance

• The primary purpose of site analysis is to evaluate a site's opportunities and constraints in the site design process.
• A thorough evaluation of the site is often discounted in the planning process due to time and budget constraints.
• Discovering site limitations after design or in construction can lead to costly revisions, delays, or even project abandonment.

Value of Site Analysis

• A comprehensive site analysis provides valuable information for site design, reducing the risk of errors and costly changes.
• Site analysis is considered a critical first step in planning and designing a site, as it informs the design process and ensures a successful project.

Site Analysis Purposes

• Site analysis purposes include identifying site opportunities and constraints, assessing site conditions, and informing the design process.

Aerial Photography

• Photography firms may be reluctant to enlarge photographs for site planners due to concerns about image quality and distortion.
• The most accurate part of a photograph is the center, with distortion increasing towards the edges.
• Enlarged aerial photographs are valuable for site planners, as they provide detailed information about site conditions and features.
• The curvature of the lens affects the photograph, causing distortion and inaccuracy at the edges.

Site Analysis Tools and Methods

• Slope analysis is used to evaluate site topography and identify potential drainage or erosion issues.
• A soil survey provides information about soil type, composition, and potential limitations.
• Building orientation is important to consider, as it affects energy efficiency, daylighting, and views.
• The USGS provides information about topography, hydrology, and geology through various sources, including the USGS topographic maps.
• The USDA Plant Hardiness Zone Map considers the average annual extreme minimum temperature in an area.

Challenges and Considerations

• Developing sites in low or flat areas can be challenging due to drainage and flooding issues.
• The USGS provides information about natural disasters through the Center for Integration of Natural Disaster Information (CINDI).
• Aspect is an important consideration in site planning, as it affects microclimate, soil erosion, and vegetation growth.
• FEMA's website provides information about flood zones, flood insurance, and disaster mitigation.

Vegetation and Ecology

• An assessment of existing vegetation is important for site analysis, as it provides information about site conditions and potential ecological constraints.
• The presence of water-tolerant plant species indicates a site with wet or flooded conditions.
• A designer should consult local or state sources prior to making a site visit to gather information about local regulations and site conditions.

Tree Evaluation and Aerial Photogrammetry

• James Urban's tree evaluation methodology primarily focuses on tree size, species, and condition.
• Aerial photogrammetry provides accurate and detailed information about site topography and features.
• The primary benefit of aerial photogrammetry is its ability to provide detailed information about site conditions and features.
• Aerial photography can only be collected during winter months in some areas, due to leaf cover and vegetation.

Existing Aerial Photography and ASTM Standards

• Existing aerial photography provides valuable information about site conditions and features for site designers.
• ASTM D5518-94e1 provides guidance on the acquisition and analysis of aerial photography.
• Many private firms have access to aerial photography databases, which can be used for site analysis.
• The American Society for Testing and Materials (ASTM) Standard Guide for Acquisition provides guidance on the acquisition and analysis of aerial photography.

Limitations and Considerations

• A limitation of photogrammetry is that it can only be used in areas with suitable weather conditions and lack of vegetation.
• The first consideration of the site analysis is the proposal phase, which is critical in determining the project's feasibility.
• The typical concerns for commercial projects in terms of site location include accessibility, visibility, and environmental factors.
• A site characterization includes information about site conditions, topography, and features.
• Site analyses are usually conducted in two steps, including a preliminary analysis and a detailed analysis.
• A valuable source of topographic information for site analysis is the USGS topographic maps.
• It is essential to have a clear understanding of the contribution made by the site to ensure a successful project.