11-18-2018, 09:47 AM
Threshold analysis :
The application of threshold analysis gained significance due to failure of physical planning in Poland. It was used to determine policies for spatial development in post war reconstruction.
It attempts to rationalize and control the process of growth. Another aspect was close association of economics and urban planning.
It is a technique that is applied to process of formulation and comparing alternative strategies for development of towns.
Therefore this has been made integral part of structure plan in UK.
Concept of thresholds and threshold costs :
Threshold theory is based on the observation that towns encounter limitations to their expansion due to physical features, existing land use , and technology of infrastructure.
There is observation that physical growth of towns is not smoothly continuous but proceeds in stages marked by successive limitations which have been called as thresholds. These thresholds are not insurmountable but can be overcome only at additional( some times very High) development investments known as threshold costs.
Thus it can be inferred that capital investment cost for the expansion of a town will change over time disproportionately to increasing number of inhabitants and will reflect periods when additional lump sum must be spent to open successive areas for further development.
In general the costs necessary to locate new inhabitant in a town (Ct=total cost) are at least two fold.
1) Normal cost (Cn): These costs are connected with given locations of construction necessary to accommodate new inhabitants and would have to be spent in any case. These costs are dependent on type and density of dwellings, site servicing and development and the cost of material, labour, etc.
2) Additional cost (Ca): These cost result from existing conditions and characteristics of given
The diagram below illustrates these type of costs. It is clear that the need to over come a given threshold may result in a violent rise in additional costs Ca.
![[Image: attachment.php?aid=562]](http://www.frontdesk.co.in/forum/attachment.php?aid=562)
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The overstepping of the threshold limitation i.e. completion of all investments necessary to open new land for town expansion, results in a decline in these costs. The peak points on the cost curve are in fact one of the ways in which thresholds can be presented.
Threshold costs may be categorised into those which must be spent before the land is made suitable for development( e.g. a bridge , or access road)
Second type which are spread over the whole period of development ( such as cost connected with building on land with low bearing capacity )
Method of threshold analysis
Stage 1.
Delineation of area to be surveyed (should be as far as possible homogeneous)
Stage 2:
Analysis of factors affecting town development
A) Physiographic suitability of land for urban development, such as Natural features are slopes, woodlands, swamps etc. whether land is suitable for development.
B) The possible extension of public utility and transportation systems. Main relevant infrastructure may be water supply, power etc.
The hindrances may be forest lands, heritage areas,
Land available for development without extra cost, Existing urban structure where there is blighted areas, undeveloped areas in built up areas, such areas are available for immediate development.
Analysis of decentralised patterns :
Frequently and expanding town eventually comes up against so expensive threshold limitation that further expansion seems endangered. In this case it is better to have satelite towns in decentralised form
Application to Regional Planning :
A) When alternative locations of some significant investment are to be decided within a region. This analysis will give costs connected at different locations.
B) It will indicate where industry and services may be located in the region.
It will act as a tool to indicate regional distribution of growth which would give relatively minimal costs and to select regional growth points on a rational and economically sound basis.
Application in Urban growth :
Threshold Analysis operates in an urban growth situation in which there exists an increase in demand for public services: these services are assumed to exhibit no externalities either positive or negative. The nature of growth or its stimuli are not considered. Malisz documents four general problem areas for development:
(1) the diversity of the natural environment
(2) the existing land use pattern
(3) the technology of the existing infrastructure systems
(4) the inertia represented by the existing structural units of the urban area.
Limitations of threshold analysis
• It should not be taken as comprehensive tool for economic evaluation of planning solutions as it is primarily concerned with threshold costs rather than total costs.
• Threshold analysis dose not take benefits into account.
• Costs estimates are rough being done at the strategic stages of planning .
The application of threshold analysis gained significance due to failure of physical planning in Poland. It was used to determine policies for spatial development in post war reconstruction.
It attempts to rationalize and control the process of growth. Another aspect was close association of economics and urban planning.
It is a technique that is applied to process of formulation and comparing alternative strategies for development of towns.
Therefore this has been made integral part of structure plan in UK.
Concept of thresholds and threshold costs :
Threshold theory is based on the observation that towns encounter limitations to their expansion due to physical features, existing land use , and technology of infrastructure.
There is observation that physical growth of towns is not smoothly continuous but proceeds in stages marked by successive limitations which have been called as thresholds. These thresholds are not insurmountable but can be overcome only at additional( some times very High) development investments known as threshold costs.
Thus it can be inferred that capital investment cost for the expansion of a town will change over time disproportionately to increasing number of inhabitants and will reflect periods when additional lump sum must be spent to open successive areas for further development.
In general the costs necessary to locate new inhabitant in a town (Ct=total cost) are at least two fold.
1) Normal cost (Cn): These costs are connected with given locations of construction necessary to accommodate new inhabitants and would have to be spent in any case. These costs are dependent on type and density of dwellings, site servicing and development and the cost of material, labour, etc.
2) Additional cost (Ca): These cost result from existing conditions and characteristics of given
The diagram below illustrates these type of costs. It is clear that the need to over come a given threshold may result in a violent rise in additional costs Ca.
You have to register as member and login to see above images [img] attached in the forum post
The overstepping of the threshold limitation i.e. completion of all investments necessary to open new land for town expansion, results in a decline in these costs. The peak points on the cost curve are in fact one of the ways in which thresholds can be presented.
Threshold costs may be categorised into those which must be spent before the land is made suitable for development( e.g. a bridge , or access road)
Second type which are spread over the whole period of development ( such as cost connected with building on land with low bearing capacity )
Method of threshold analysis
Stage 1.
Delineation of area to be surveyed (should be as far as possible homogeneous)
Stage 2:
Analysis of factors affecting town development
A) Physiographic suitability of land for urban development, such as Natural features are slopes, woodlands, swamps etc. whether land is suitable for development.
B) The possible extension of public utility and transportation systems. Main relevant infrastructure may be water supply, power etc.
The hindrances may be forest lands, heritage areas,
Land available for development without extra cost, Existing urban structure where there is blighted areas, undeveloped areas in built up areas, such areas are available for immediate development.
Analysis of decentralised patterns :
Frequently and expanding town eventually comes up against so expensive threshold limitation that further expansion seems endangered. In this case it is better to have satelite towns in decentralised form
Application to Regional Planning :
A) When alternative locations of some significant investment are to be decided within a region. This analysis will give costs connected at different locations.
B) It will indicate where industry and services may be located in the region.
It will act as a tool to indicate regional distribution of growth which would give relatively minimal costs and to select regional growth points on a rational and economically sound basis.
Application in Urban growth :
Threshold Analysis operates in an urban growth situation in which there exists an increase in demand for public services: these services are assumed to exhibit no externalities either positive or negative. The nature of growth or its stimuli are not considered. Malisz documents four general problem areas for development:
(1) the diversity of the natural environment
(2) the existing land use pattern
(3) the technology of the existing infrastructure systems
(4) the inertia represented by the existing structural units of the urban area.
Limitations of threshold analysis
• It should not be taken as comprehensive tool for economic evaluation of planning solutions as it is primarily concerned with threshold costs rather than total costs.
• Threshold analysis dose not take benefits into account.
• Costs estimates are rough being done at the strategic stages of planning .