submission

1. M. PLAN I SEMI
ASSIGNMENT 4
THRESHOLD ANALYSIS
PLANNING TECHNIQUES
S U B M I T T E D T O : P R O F . J A N A K K A U R
S U B M I T T E D B Y : B H A V E S H P A T E L

2. THRESHOLD ANALYSIS
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The threshold theory is based on the observation that any urban centre encounters limitations to their
expansion due to physiographic features, existing land use and technology of infrastructure. An important
inference from this observation is that the physical growth of town is not smoothly continuous but proceeds
in stages marked by successive limitations which have been called development threshold. These
thresholds are not insurmountable and can be overcome but only at additional development investments
known as threshold costs.
-NORMAL COST ( Cn )-INDEPENDENT OF THE LOCATION OF DEVELOPMENT
- THRESHOLD COST ( Ca )-DEPENDENT UPON THE LOCATION OF DEVELOPMENT
-TOTAL COST Ct
Ct= Cn +Ca

3. THRESHOLD ANALYSIS
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Town planning, in its turn, deals with several kinds of limitations to the use of land and the growth of
settlement. The conventional procedures of feasibility studies, however, do not make sufficient use of these
limitations in their methodology. It is obvious, for example, that an expanding settlement will be confronted
from time to time with limitations that have the character of thresholds. Some of these are physical: a city on
an island can expand only within the confines of its shores; tracts of marshland or steep valley sides will
stand in the way of development in certain directions. These limitations are not absolute. They can be
overcome: land can be reclaimed and artificial islands created. But crossing these thresholds demands a high
input of economic resources. Yet even on less intractable sites threshold limitations are visible. They may be
apparent first of all in the existing land use pattern: some directions may be closed to further expansion by
industrial or other uses. To pursue expansion there would necessitate the removal of those operations or
their cessation.
There is a second category in the form of technological thresholds. A city functions on the basis of a range of
engineering systems that together constitute its infrastructure: technological thresholds appear when the
extension of an existing system (e.g. water supply or transportation) is no longer possible and a new system
has to be introduced. Thirdly, there are structural limitations, which affect the internal form of the city and
necessitate its reshaping, particularly so far as its central area is concerned.

4. THRESHOLD ANALYSIS
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This technique is used to determine influence zones, urban extents and regions, attempts to rationaliz
e and control the process of urban growth and provides a quantitative tool to help decision‐making.
Thresholds based on physical limitations are comparatively easy to determine using mapping techniqu
es. Thresholds can be tangible or intangible. Tangible thresholds are those, which can be measured, qu
antified and represented. These are physical, technological and structural limitations such as land available
for development, current technology of water treatment or electricity production. Physical limitations
or threshold are restrictions imposed by physiography and topography and get physically identified in th
e form of natural features such as rivers to be crossed, hilly areas and steep slopes etc. Technological th
resholds are limitations imposed on physical growth of city, by constraints in expansion of infrastruct
ure system. Some of these thresholds can be identified spatially and some numerically for instance, waters
hed line is generally the limit of extension of sewerage system, whereas, the capacity of a sewage treatme
nt plant can be expressed in terms of number of inhabitants that can be served (numerically) identifie
d threshold. Intangible thresholds can only be understood and indirectly measured such as, socio econ
omic limitations.

5. THRESHOLD ANALYSIS
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The Process of Threshold Analysis
Part One: Analysis ƒ
Stage I: Delineation of area to be surveyed by drawing the boundaries of area as closely as possible to a hom
ogenous pattern of settlement. ƒ
Stage II: Analysis of factors affecting town/urban development such as physiographic suitability of land and
possible extension of public utilities. ƒ
Stage III: Tracing the threshold lines, delimiting areas suitable for urban development and new devel
opment areas from fundamental land development. ƒ
Stage IV: Synthesis : The information can now be correlated to form a synthesis of all factors conside
red on basis of which, the lines of urban development thresholds can be defined. Physical thresholds are sho
wn spatially on base map and quantitative thresholds such as population figures, investment, power or water
supply requirement can be expressed. ƒ

6. THRESHOLD ANALYSIS
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The Process of Threshold Analysis
Part One: Analysis ƒ
Stage V: Land is subdivided for main functions of city within the successive physical threshold areas.
This is done generally for two main functions, suitable area for industry and suitable area for other urban us
es, priority being given based on vision of development. ƒ
Stage VI: The calculation of capacity of residential areas within the first and successive threshold lines in
relation to quantitative threshold figures in order to define the approximate number of inhabitants, w
hich may be accommodated. ƒ
Stage VII: The calculation of averages of industrial areas within the first and successive threshold lines to d
efine their potential for industrial location after considering the quantitative threshold figures.

7. THRESHOLD ANALYSIS
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The Process of Threshold Analysis
Part Two: Outline of Economic Assessment ƒ
Stage VIII: Calculating the approximate capital investment costs necessary to overcome each threshold
within the examined area. ƒ
Stage IX: Calculating the following efficiency indices for each successive threshold area: ƒ
Cost of each new inhabitant ƒ
Cost per acre of land suitable for development.
In regional planning indirect use of quantified results can be used in decision making among alternative loca
tions for some significant investment within the region, while preparing a comprehensive regional policy for
the distribution of the expected influx of population.

8. THRESHOLD ANALYSIS
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•QUANTITATIVE METHOD
•ILLUSTRATE THE CONSEQUENCES IN TERMS OF COST OF DEVELOPING ALTERNATIVE AREAS.
•INTRODUCE THE QUANTIFICATION OF THRESHOLD COST INTO PHYSICAL PLANNING
TECHNIQUE.
FINALIZING LAND SUITABILITY
FOR THE FORMULATION AND COMPARISON
OF DEVELOPMENT
•LOCATION ORIENTED
TECHNIQUE

9. TYPES OF THRESHOLDS
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THRESHOLD
GRADE
STEPPED
CAUSED BY SITE CONDITIONS
CAUSED BY LIMITATION IN
INFRASTRUCTURE SERVICES

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Grade threshold
Total
Cost No. of units
Average
Unit
Cost
No. of units
No. of units
No. of units
Total
Cost
Average
Unit
Cost
Stepped threshold
A B A B

11. SEM 1 PLANNING TECHNIQUES 11
STRUCTURE PLAN
URBAN - (CITIES, TOWNS &
URBAN AREAS)
-- APPROPRIATE FOR
EXPANDING TOWN ( POP. 5,000-
1,00,000)
-- USED FOR FORMULATING AND
COMPARING ALTERNATIVE
STRATEGIES FOR DEVELOPMENT
OF TOWNS.
-- COMPARING SITES FOR
DEVELOPMENT RESIDENTIAL
USE.
COUNTY - (GROUP OF
SETTLEMENTS)
ASSISTANCE FOR
THE PREPARATION
OF STRUCTURE
PLAN
SITUATIONS WHERE THRESHOLD ANALYSIS CAN BE USED

12. SEM 1 PLANNING TECHNIQUES 12
LOCAL PLAN
( INFORMATION GATHERED FOR
STRUCTURAL PLAN IN DETAIL)
DISTRICTS
1. PARTS OF
LARGE
TOWNS
2. WHOLE
OF A SMALL
TOWN
3. RURAL
AREAS AND
VILLAGES
ACTION AREA
1. NEW
DEVELOPMENT
2. IMPROVEMENT
3. REDEVELOPMENT
SUBJECT
RESIDENTIAL,
INDUSTRIAL,
RECREATIONAL AND
OTHER SPECIFIC
DEVELOPMENT
PROBLEMS
SITUATIONS WHERE THRESHOLD ANALYSIS CAN BE USED

13. SEM 1 PLANNING TECHNIQUES 13
SETTING THE OBJECTIVES FOR THE
ANALYSIS
IDENTIFICATION OF
ASSUMPTIONS
SETTING UP OF PARALLEL
STUDIES
DEFINITION OF DEGREE OF
ACCURACY
DEFINITION OF THE STUDY AREA
PROCESS
PROBLEM SETTING
AND PREREQUISITES
MAIN ANALYSIS
INTERPRETATION
OF RESULTS

14. SEM 1 PLANNING TECHNIQUES 14
PROCESS
PROBLEM SETTING
AND PREREQUISITES
MAIN ANALYSIS
INTERPRETATION
OF RESULTS
Definition of first and
boundary thresholds
Elimination of unsatisfactory groupings
Preparation of cost charts
Identification of critical thresholds and eliminate
the unsatisfactory groupings
Calculation of comprehensive
threshold cost

15. SEM 1 PLANNING TECHNIQUES 15
PROCESS
PROBLEM SETTING
AND PREREQUISITES
MAIN ANALYSIS
INTERPRETATION
OF RESULTS
SUMMARY OF RESULTS
REPORTS AND PRESENTATIONS
OF THE IMPLICATIONS
IMPLICATION OF THE ANALYSIS
FOR THE STRUCTURE PLAN

16. SEM 1 PLANNING TECHNIQUES 16
THRESHOLD ANALYSIS IN URBAN PLANNING
• Urban Planning can be considered as that part of the urbanization
process which is considered with defining aims and with determining
ways and means by which those aims can be attained.
• The prime responsibility of urban planning is to indicate how to
influence development processes to ensure that the resulting
structural and functional transformations of settlements lead towards
the fulfillment of the aims.
• Thresholds are known in urban planning as physical limitations
encountered by expanding towns, and the cost of overcoming these
limitations represent threshold costs.
• The method of threshold analysis permits identification of threshold
limitations, calculations of threshold costs and definition of all other
consequences of threshold overstepping. In short the method
provides a tool for evaluation of urban development possibilities.
• Practical experience and the most recent research have not only
confirmed the continuing usefulness of recent analysis in urban
planning but have also indicated broad possibilities for further
development and adaptation of threshold analysis .
INTER RELATIONSHIP WITH OTHER DISCIPLINES
Threshold analysis undertaken for the small town of
Taivalkoski, Finland to accommodate expeceted 1500
new inhabitants

17. SEM 1 PLANNING TECHNIQUES 17
ADVANTAGES:
1. It can play useful part at specific stages of planningprocess. It does not attempt to determine the future
pattern of development.
2. Location oriented technique introducing the quantification
3. of threshold costs into a physical planning technique.
LIMITATIONS
1. Should not be taken as the comprehensive tool for the economic evaluation of the planning solution as it
is concerned primarily with threshold costs.
2. It does not take in to the account the benefits ( economic and social)
3. Assumptions are the prerequisite to the application of threshold.
4. Calculations are often based on crude assumptions and must not be treated as precise cost assessment.
5. Most suitable for medium sized towns or small sized, where as complex and larger towns require more
automated data.
6. Primarily concerned with the residential area development
7. Deals with the urban development threshold and only provides general ideas on how to analyses
redevelopment threshold.
8. Process concentrates on comparing the threshold costs of various sites
LIMITATIONS AND ADVANTAGES OF THRESHOLD ANALYSIS

18. SEM 1 PLANNING TECHNIQUES 18
•Threshold analysis is neither a complete planning theory nor a ultimate solution for all kind of planning
problems.
• It is a problem identifyingtechnique
•This does not measure the benefits of urban alternatives forms. It indicates the cost and identifies the
factors responsible for cost variations
•Advocacy of this analysis requires huge Responsibility
CONCLUSION

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Urdpfi Guidelines
Https://Link.Springer.Com/Chapter/10.1007/978-1-349-15404-3_17
Threshold Analysis Manual
By The Planning Research Unit Department Of Urban Design And Regional Planning, University OfEdinburgh
Threshold Analysis
By J Kozlowski And J T Hughes; Architectural Press, London, Halsted Press , Newyork
Threshold Approach In Urban, Regional And Environmental Planning Theory And Practice;
ByJerzy Kozlowski, University Of Queensland Press, London, Newyork
CONCLUSION

20. THANK YOU
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SEM 1 PLANNING TECHNIQUES