20 Onsite and Offsite Factors You Should Consider for Site Analysis

Site planning is the art of arranging structures on a land and shaping the space in between them. Site analysis is a technique which is part of  site planning that helps us understand the various factors at play. 

What is the need for site analysis?

  • To learn the strengths and weaknesses of the site.
  • To understand the site and derive the form and function of the building based on the factors.
  • To fix issues on the site, if any.
  • To try and predict the potential future changes in or around the site and design the building accordingly.

The major site factors can be divided into onsite and offsite factors in the book ‘Site Analysis’ by Edward White.

Onsite factors Checklist for Site Analysis

They refer to the factors present on the site.

The major ones are-

  1. Location
  2. Size
  3. Topography
  4. Vegetation
  5. Drainage
  6. Groundwater
  7. Soil
  8. Danger signals
  9. Man-made features
  10. Legal factors
  11. Utilities
  12. Right of way
  13. Circulation
  14. Microclimate
  15. Sensory 

Offsite factors Checklist for Site Analysis

These refer to the features around the site.

Some of them are-

  1. Climate
  2. Access
  3. Neighborhood
  4. Culture
  5. Views 

Onsite factors 

1. Location

Location of Site
Location of Site
  • Coordinates
  • Area of the site
  • Names of the adjacent road
  • Landmarks
  • Nearest services like hospitals, airports, schools, stores etc.

2. Size

Size of the Site
Size of the Site
  • The length and breadth of the land should be noted.
  • The total buildable area after subtracting the area for setbacks and easements should also be calculated.

3. Vegetation

Vegetation in Site Analysis
Vegetation in Site Analysis
  • Includes the trees, shrubs and groundcover on site.
  • They affect the wind pattern and drainage of the site.
  • Weeds and ground cover can be removed while trees should be retained.
  • The building can be designed to use them as buffer or shading devices.

4. Topography

Contours on the Site
Contours on the Site
  • Refers to the features of the surface of the land.
  • Contour, high points, low points, ridges, valleys and flat land should be documented.
  • Flat surface is best used for intensive activities.
  • Steep slopes are hard to construct and move on.
  • Buildings can be constructed between 1:6 and 1:12 slope.

5. Drainage

Surface Drainage Patterns
Surface Drainage Patterns

This depends on the contour of the land.

6. Groundwater

  • Refers to the water below the surface level.
  • Construction should be done considering the depth of the water table.

7. Soil 

Soil Bearing Capacity of Site
Soil Bearing Capacity of Site
  • The soil should be tested to determine its soil-bearing capacity.
  • Depending on the type of soil, the foundation is chosen.

8. Danger signals are exhibited by some features like

  • Rocks lying close to the surface
  • High water table
  • Underground stream
  • Loose clay or  fine sand

They call for expert analysis and special construction.

9. Man-made features include

  • Walls
  • Fences
  • Hydrants
  • Power poles
  • Pavements

10. Legal factors include 

Legal Restrictions of Site
Legal Restrictions of Site
  • Ownership of land
  • Setbacks- minimum open space around a building
  • FSI (floor space index)- total built area/total plot area
  • Height restrictions
  • Allowed uses of the site

All buildings should be constructed with respect to the development control regulations.

11. Utilities

Utilities at Site
Utilities at Site
  • Includes services like water, sewage, electricity, gas.
  • Can be under or above ground level.
  • The distance of these facilities from the site should be noted.
  • Some services like HTL (high tension lines) passing through the site can make it hazardous.

12. Right of way

Right of Way
Right of Way

A part of the site can be used to provide access to another piece of land.

13. Circulation on site is of two types

Onsite Circulation
Onsite Circulation
  • Pedestrian
  • Vehicular

14. Microclimate

Apart from the general climate of the surrounding area, the site can have a microclimate determined by the following factors-

  • Location of structures
  • Vegetation
  • Surface materials
  • Topography
  • Water bodies
  • Surrounding buildings

15. Sensory factors are

Sensory Factors at Site
Sensory Factors at Site
  • Visual views from the site.
  • Olfactory- the smell from surrounding vegetation and buildings.
  • Audible- sounds from roads and neighboring areas.
  • Tactile- wind influenced by vegetation and buildings.

Offsite factors

1. Climate includes

Climate Factors on Site
Climate Factors on Site
  • Rainfall
  • Wind direction
  • Sun path
  • Humidity
  • Temperature

The variations in these factors throughout the day and year and possible natural calamities like floods or tsunamis should also be considered.

The shading and ventilation of the building depends on these factors.

2. Access refers to

  • The different ways of approaching the site.
  • The roads around the site.
  • Location of site with respect to the roads,
  • Usage and traffic on these roads.

3. Neighborhood includes

Neighborhood Features of Site
Neighborhood Features of Site
  • Existing buildings.
  • Open spaces in the vicinity.
  • Buildings with historical context.
  • Vernacular context of the area.
  • Possible hazardous waste disposal areas.

4. Cultural factors are

Cultural Factors of Site
Cultural Factors of Site
  • Population density
  • Age distribution
  • Income and employment
  • Family structures
  • Crime patterns

These help in the zoning of the site.

5. Views include

Views on Site
Views on Site
  • Positive and negative views.
  • How the site looks from different points and how these might change with distance or time.

What is the importance of thorough site analysis?

  • To have greater efficiency while designing.
  • To discover the interrelationship between site factors.
  • To maximize data triggers for design conceptualization.
  • To avoid legal implications

Hence it becomes necessary to carefully understand and record the above-mentioned factors while analyzing the site so as to use it to the best of its abilities.

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