Threshold Analysis

THRESHOLD THRESHOLD ANALYSISANALYSIS

LINTA JOY APARA BANERJEE POOJA AGARWAL NEHA POTDAR ROSY GOGOI DEBLEENA SAHA ANAND

BACKGROUND

•PIONEERED IN POLAND BY B. MALIS IN EARLY

60S.

•INTRODUCED TO GREAT BRITAIN IN 1965 BY

PLANNING RESEARCH INSTITUTE IN ITS REGIONAL

PLAN FOR THE GRANGE MOUTH / FALKRIK GROWTH

AREA – SCOTLAND.

THRESHOLD ANALYSIS

•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

• IS THE SUCCESSIVE LIMITATIONS PUNCTUATING

THE PHYSICAL GROWTH OF TOWN.

• CAN BE OVERCOME THROUGH THRESHOLD

COST.COST

-NORMAL COST ( Cn )-INDEPENDENT OF THE LOCATION OF DEVELOPMENT

- THRESHOLD COST ( Ca )-DEPENDENT UPON THE LOCATION OF DEVELOPMENT

-TOTAL COST Ct Ct= Cn +Ca

DEVELOPMENT THRSHOLD

TYPES OF THRESHOLDS

CAUSED BY SITE CONDITIONS

CAUSED BY LIMITATION IN INFRASTRUCTURE SERVICES

Grade threshold

Tota

l C

ost

No. of units

Avera

ge

Unit

Cost

No. of units

No. of unitsNo. of units

Tota

l C

ost

Avera

ge

Unit

Cost

Stepped threshold

A B A B

SITUATIONS WHERE THRESHOLD ANALYSIS CAN BE USED :

DEFINITION OF THE STUDY AREA

PROCESS

PROBLEM SETTING AND PREREQUISITES

MAIN ANALYSISINTERPRETATION OF RESULTS

PROCESS

PROBLEM SETTING AND PREREQUISITES

MAIN ANALYSISINTERPRETATION OF RESULTS

Definition of first and boundary thresholdsElimination of unsatisfactory groupings

Preparation of cost charts

Identification of critical thresholds and eliminate the unsatisfactory groupings

Calculation of comprehensive threshold cost

PROCESS

PROBLEM SETTING AND PREREQUISITES

MAIN ANALYSISINTERPRETATION OF RESULTS

SUMMARY OF RESULTS

REPORTS AND PRESENTATIONS OF THE IMPLICATIONS

IMPLICATION OF THE ANALYSIS FOR THE STRUCTURE PLAN

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

An ultimate environmental threshold (UET):

• The stress limit beyond which a given ecosystem becomes incapable of returning to its original condition and balance. Where these limits are exceeded as a result of functioning or development of particular tourist or other activities, a chain reaction is generated leading towards irreversible environmental damage of the whole eco-system or of its essential parts

INTER RELATIONSHIP WITH OTHER DISCIPLINES (2/3)

Live application of UET method in preparing a plan for the Tatry national park , Poland

THRESHOLD APPROACH IN ENVIRONMENTAL PLANNING•Environmental planning can be defined as a process whereby regional and national resource conservation or development plans are created in ways that consciously seek to minimize long term negative effects on existing levels of environmental quality

UniquenessTransformat

ion

UET

Resistance

Minimal Partial Total

Reversible Irreversible

UETs can be determined by confronting these threats

THRESHOLD APPROACH IN REGIONAL PLANNING•Threshold approach is concerned with aspects of scarcity. Since it aims at defining the amount of land suitable for development from the physiological standpoint, the amount of land being served by existing public utility network and so on. This information, however, whether used by regional planners or others has been derived so far from the analyses undertaken at the urban planning level and therefore limited to the local conditions. The regional planning implications arise only from the fact that the relative impact and significance of particular local thresholds may influence the desired evolution of the settlement pattern.

INTER RELATIONSHIP WITH OTHER DISCIPLINES (3/3)

LIMITATIONS AND BENEFITS OF THRESHOLD ANALYSIS•It can play useful part at specific stages of planning process. It does not attempt to determine the future pattern of development.•Location oriented technique introducing the quantification 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. Implications of threshold analysis while comparing planning solutions are valid if all other factors including benefits are considered equal.

3. It does not take in to the account the benefits ( economic and social)

4. Assumptions are the prerequisite to the application of threshold.

5. Calculations are often based on crude assumptions and must not be treated as precise cost assessment.

6. Most suitable for medium sized towns or small sized, where as complex and larger towns require more automated data.

7. Primarily concerned with the residential area development

8. Deals with the urban development threshold and only provides general ideas on how to analyses redevelopment threshold.

9. Process concentrates on comparing the threshold costs of various sites

10.Concentrate on calculating “direct threshold cost “ capital cost and gives only general guidance on the calculation of indirect threshold cost ( exploitation cost).

BENEFITS

Benefits of using threshold analysis can be explained under two groups

IN PREPARATION OF STRUCTURE PLANS•Helps to analyse the degree of suitability of sites for urban development.•Identifies differences in cost of developing alternative sites.•Allows the design of a town’s physical structure to be made in such a way the development is integrated with overcoming of threshold limitations.•Can function as input data for other techniques eg: cost benefit analysis, planning balance sheet.

IN DECISION MAKING•Local authorities can use the results for decision making •The information provided can be used for formulating corporate investment plans.•The information also help local authorities to negotiate better with developers and industrialists.

CONCLUSION

• THRESHOLD ANALYSIS IS NEITHER A COMPLETE PLANNING THEORY NOR A PANACEA FOR ALL KIND OF PLANNING PROBLEMS.

• IT IS A PROBLEM IDENTIFYING TECHNIQUE

•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

REFERENCE REFERENCE

THRESHOLD ANALYSIS MANUAL BY THE PLANNING RESEARCH UNIT DEPARTMENT OF URBAN DESIGN AND REGIONAL PLANNING, UNIVERSITY OF EDINBURGH

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; BY JERZY KOZLOWSKI, UNIVERSITY OF QUEENSLAND PRESS, LONDON, NEWYORK

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