GIS based PAVEMENT MAINTENANCE &
MANAGEMENT SYSTEM (GPMMS)
A Thesis Submitted in Partial Fulfillment of the
Requirements for the Award of the Degree of
Master of Technology
In
Civil Engineering
(Traffic and Transportation Planning)
NIJU.A
Roll No. CEO4M024Department of Civil Engineering
National Institute Of Technology Calicut
Calicut, Kerala 673 601
May 2006
Certificate
This is to certify that the thesis entitled
“GIS based PAVEMENT MAINTENANCE & MANAGEMENT SYSTEM (GPMMS)”is a record of the
bona fide work done by
Mr. NIJU.A (Roll No. CE04M024)under my
supervision and guidance. This thesis is submitted to the National
Institute of Technology Calicut in partial fulfillment of the requirements
for the award of the degree of Master of Technology in Civil
Engineering (Traffic & Transportation Planning) during 2004-06.
Sri M.V.L.R. Anjaneyulu Dr. S. Chandrakaran
Programme Coordinator
Professor and Guide
Department of Civil Engineering
Department of Civil EngineeringN.I.T. Calicut
National Institute of Technology Calicut, Kerala-673601 NITC, Calicut Date : Dr. V. Mustafa Professor & HeadDepartment of Civil Engineering National Institute of Technology Calicut, Kerala-673601
ACKNOWLEDGMENTS
I express my profound sense of gratitude to Dr. S. CHANDRAKARAN, Professor, Department of Civil Engineering, for his systematic guidance, valuable advice and constant encouragement throughout this project work.
I express my sincere gratitude to Dr. B.N NAGARAJ, Professor (Retd.), Department of Civil Engineering, National Institute of Technology, Calicut, for his valuable suggestions for the improvement of this work.
I am thankful to Dr. V. MUSTAFA, Professor & Head, Department of Civil Engineering and Dr. N GANESAN, former Head of the Department of Civil Engineering, National Institute of Technology, Calicut for providing all the facilities in the department.
I wish to convey my sincere thanks to Mr. JAYASURIAN. M, MCA student, NITC, for all his supports and backups render to me throughout, then Mr. SIJU, Lab Assistant, Transportation Engineering laboratory and all members of transportation family for their wholehearted co-operation.
Finally I would like to extend my deepest gratitude to all my friends who gave valuable suggestions and encouragement especially Ms. KEERTHI.M.G, MTech, Traffic and Transportation, which were very helpful to me throughout this project work.
ABSTRACT
The road networks are capacity constraint and structurally deficient due to lack of timely maintenance, rehabilitation and upgradation. This has adversely affected the traffic movement, resulting into higher operating costs and delays. Maintenance and upgradation of such a large network is a challenging task because of the logistics and constraints of resources. There is a need to manage the network more efficiently in a scientific manner; the most important aspect lacking is the application of information system.
Therefore there is a need to establish a centralized facility where information on road and road transportation can be utilized for the development of effective and efficient maintenance and rehabilitation measures and for planning upgradation strategies.
Aim of this work is to build a GIS based system that provides information for use in implementing cost-effective reconstruction, rehabilitation, and preventive maintenance programs and results in pavement design to accommodate current & forecasted traffic and pavement deteriorations, in a safe, durable, and a cost-effective manner.
A well-designed geographic information system (GIS) provides a platform on which all aspects of the PMMS process can be built. The resulting system, GPMMS, represents a significant enhancement of all aspects of the PMMS process. A variety of spatially integrated data are important to pavement management decision making. GIS technology is shown to be the most logical way of relating these diverse, but relevant, data.
The GIS based pavement management system would eventually lead to the development of the frame work for GIS based Pavement Maintenance & Management System (GPMMS). Here I had reviewed the role of GIS (GeoMedia environment) for pavement management system.
Looking at the PMMS process in its entirety leads to the enumeration of a set of functions to be embedded in the GIS platform that is required for effective GPMMS. These functions include thematic mapping, a flexible data base editor,
Linear Referencing System, dynamic segmentation, statistics, charting, network generation, and integration with external programs.
The most important pavement management tools in GeoMedia are Linear Referencing System and Dynamic Segmentation. Dynamic segmentation is the overlay and display of attributes describing a linear referenced road network. Dynamic segmentation can accommodate multiple attribute tables, describing a road network, without requiring duplication of network geometry or data. Only a single, graphic representation of the highway network is required. The locations of attribute records along the road network are identified using a linear referencing method.
A comprehensive plug-in software, GeoMedia Pavement Maintenance and Management Assistant (GPMMA) for GeoMedia has also been developed, which provides no bounds for PMMS analysis in GeoMedia. Important features in GPMMA are Deterioration prediction, Economic analysis, BBD overlay design, Maintenance Prioritization, Overlay Cost Calculator, Maintenance scheduler etc
An exemplar GPMMS analysis was carried out on the whole of Calicut district. A well scaled georeferred Calicut district road map was developed in GeoMedia, GIS environment. Almost all the available data, including bridge inventory details, culvert inventory details, and condition survey details had been incorporated using dynamic segmentation for the analysis.
Altogether a concise and succinct approach for pavement maintenance and management have been developed using GeoMedia in hand with GPMMA.
CONTENTS
TITLE PAGE NO CERTIFICATE ACKNOWLEDGEMENT i ABSTRACT ii CONTENTS ivLIST OF FIGURES viii
LIST OF TABLES xi
CHAPTER 1 INTRODUCTION 1-6
1.0 GENERAL 1
1.1 PAVEMENT MAINTENANCE & MANAGEMENT SYSTEM 1
1.2 FEATURES OF PMMS 2
1.3 PMMS INPUTS 2
1.4 ANALYTICAL TOOLS AND OUTPUTS 2
1.5 STRUCTURE OF PMMS 3
1.6 NEED FOR THE STUDY 4
1.7 OBJECTIVES OF THE STUDY 4
1.8 PROBLEMS, CHALLENGES AND THREATS 5
1.9 SCOPE OF THE STUDY 5
1.10 ORGANIZATION OF THE DISSERTATION WORK 5
1.11 CONCLUSIONS 6
CHAPTER 2 LITERATURE REVIEW 7-24 2.0 GENERAL 7
2.1 STATE - OF - THE – ART 7
2.2 GLOBAL PMMS SCENARIO 8
2.2.1 United Stases of America 8
2.2.2 Canada 10 2.2.3 Australia 11 2.2.4 United Kingdom 12 2.2.5 France 13 2.2.6 Germany 13 2.2.7 Denmark 14
2.2.8 New Zealand 14
2.2.9 Sweden 15
2.2.10 Austria 16
2.2.11 Indian Scenario 16
2.2.12 Studies at universities and Research Institutions 17
2.3 GIS TECHNOLOGY AND BENEFITS 20
2.4 INFORMATION TECHNOLOGY FOR PMMS 21
2.5 CONCLUSION 24
CHAPTER 3
A BRIEF REVIEW OF GeoMedia 25-34
3.0 GENERAL
25 3.1 GEOMEDIA PROFESSIONAL 25 3.1.1 GeoWorkspace 25 3.1.2 Co-ordinate system 26 3.1.3 Warehouse 27 3.1.4 Windows 27 3.1.5 Legend 27
3.1.6 Feature and feature class 29
3.2 FUNCTIONS OF GEOMEDIA 31
3.2.1 Digitization 31
3.2.2 Queries 31
3.3 GEOMEDIA TRANSPORTATION MANAGER 5.2 32
3.3.1 Linear referencing 32
3.3.2 Dynamic segmentation 33
3.3.3 Routing network 33
3.3.4 Routing analysis 33
3.4 CONCLUSIONS 34
CHAPTER 4 PAVEMENT MAINTENANCE & MANAGEMENT ASSISTANT 35-55
4.0 GENERAL
35
4.1 AN OVERVIEW OF GPMMA 35
4.2 BEHIND GPMMA 35
4.2.1 GPMMA & External Component Installation 35
4.2.2 GPMMA Command Installation 37
4.3 GPMMA OVERVIEW & IMPORTANT FEATURES 39
4.3.1 PMMA Deterioration Prediction 40
4.3.1.1 Prediction of Yearly Change in CSA 40
4.3.1.2 Prediction of Yearly Change in Deflection 41
4.3.1.3 Prediction of Yearly Change in Unevenness 41
4.3.1.4 Prediction of Yearly Change in PSR 41
4.3.2 PMMA Economic Analysis 42
4.3.2.1 Construction Cost 43
4.3.2.2 Vehicle Operation Cost 43
4.3.3 PMMA BBD Overlay Design 46
4.3.3.1 Conversion of Curves into Mathematical Forms 47
4.3.4 PMMA Maintenance Prioritisation 50
4.3.4.1 Index Ranking Method 50
4.3.4.2 Percentile Ranking Method 51
4.3.4.3 Weightages Given For Various Parameters 52
4.3.5 PMMA Overlay Cost Calculator 53
4.3.6 PMMA Maintenance Scheduler 53
4.3.7 Hooks to External Softwares 54
4.4 CONCLUSIONS 55 CHAPTER 5
GPMMS INPUTS 56-67 5.0 GENERAL
56 5.1 GPMMS INPUTS 56 5.2 GPMMS DATABASE 56 5.2.1 Inventory Data 57 5.2.2 Construction Data 58 5.2.3 Traffic Data 59 5.2.4 Condition Data 60
5.2.4.1 Physical Distress Data 60
5.2.4.2 Roughness Data 61
5.2.4.3 Structural Capacity Data 62
5.2.4.4 Friction Data 62
5.3 UPDATING GPMMS DATABASE 62
5.3.2 Dynamic Segmentation 64
5.4 DATA ENTRY 65
5.5 GEOREFERENCED DIGITISED BASE MAP 66
5.6 PMMS ANALYSIS TOOLS (GPMMA) 67
5.7 CONCLUSIONS 67
CHAPTER 6
GPMMS OUTPUTS & RESULTS 68-88
6.0 GENERAL
68
6.1 GPMMS OUTPUTS 68
6.1.1 Thematic Maps 68
6.1.2 Deterioration Prediction 73
6.1.3 Economic Analysis 74
6.1.3.1 Net Present Value Method (NPV) 75
6.1.4 Maintenance Scheduling 79
6.1.5 Maintenance Prioritization 80
6.1.6 BBD Overlay Design 83
6.1.7 Overlay Cost Calculation 84
6.1.8 Other Outputs 85
6.2 CONCLUSIONS 88
CHAPTER 7 CONCLUSIONS, LIMITATIONS & SCOPE OF FUTURE WORK 89-90
7.0 GENERAL
89
7.1 SUMMARY AND CONCLUSIONS
89
7.2 LIMITATIONS AND SCOPE OF FURTHER WORK 90
7.3 CONCLUSIONS 90
LIST OF FIGURES
FIGURE NO. TITLE PAGE NO. 1.1 Conceptual representation of PMMS 32.1 Structure of the PMS implemented in the Oklahoma State 10 2.2 Framework of Canadian Pavement Management System 11
2.3 Principal Components of HAPMS 12
2.4 Structure of VISAGE and GIRR 13
2.5 Three Levels of PMS Along With Three Types of Databases 15 2.6 Inputs – Analysis – Output - Chart 21
3.1 A Legend 28
3.2 Style Keys representing feature classes in Legend 29 3.3 Style Keys representing errors in Legend 29
3.4 Illustrating Linear Referencing 33
4.1 GPMMA & External component installation setup files 36 4.2 GPMMA & External component installation setup-1 36 4.3 GPMMA & External component installation setup-2 37 4.4 GPMMA Command Installation setup-1 37 4.5 GPMM Command Installation setup-2 38 4.6 GPMMA Command Installation setup-3 38 4.7 External Software Installation linking form 38 4.8 PMMA command installed in menubar 39
4.9 PMMA command windows 39
4.10 GUI for PMMA Deterioration predictor 42 4.11 GUI for PMMA Economic analysis 1 45 4.12 GUI for PMMA Economic analysis 2 45 4.13 GUI for PMMA Economic analysis 3 46
4.14 GUI for PMMA BBD overlay design 49
4.15 Access Database for PMMA BBD overlay design 49
4.17 GUI for Priority Ranking 52 4.18 GUI for PMMA Overlay Cost Calculator 53 4.19 Graph showing best time for Maintenance scheduling 54 4.20 GUI for PMMA Maintenance scheduler 54 4.21 Snap Shots of External Softwares windows 55 5.1 Microsoft Access Database showing Inventory data 58 5.2 Microsoft Excel Database showing Traffic data 59 5.3 Microsoft Access Database showing Physical distress data 60 5.4 Microsoft Access Database showing Roughness data 61 5.5 Linear Referencing Command Toolbar & Work Flow 63 5.6 Linear Referenced Access Warehouse table & road network 63 5.7 Basic Concepts of Dynamic Segmentation 64 5.8 Dynamic Segmentation Command Toolbar & Work Flow 65 5.9 Microsoft InfoPath form Query View and Data Entry View 66 5.10 Georeferenced Raster Images & Digitized Map 67 6.1 Thematic Map showing the lengthwise distribution of MDR 69 6.2 Thematic Map showing the bridge inventory details 70 6.3 Thematic Map showing the bridge attribute details 70 6.4 Thematic Map showing the ODR condition details 71 6.5 Thematic Map showing the SH condition details 71 6.6 Thematic Map showing the Culvert inventory details 72 6.7 Thematic Map showing the Culvert attribute details 72 6.8 Thematic Map showing the IRQP Phase of NH 73 6.9 Deterioration Prediction - output 74 6.10 Economic Analysis – Deterioration Prediction 76 6.11 Economic Analysis – Overlay Cost Calculation 77 6.12 Economic Analysis – NPV & Strategy Selection 78 6.13 Present Serviceability Index Vs Age of Pavement 79
6.14 Maintenance scheduling- output 80
6.15 Maintenance prioritisation of MDR’s 81 6.16 Maintenance prioritisation of SH’s 81
6.17 BufferZones & Closest path around Koduvally 82 6.18 BufferZones & Closest path around Koduvally 83
6.19 BBD Overlay design-output 84
6.20 Overlay cost calculation -output 85 6.21 Customised Window for chart output 85 6.22 Bar Chart showing Raveling details along the stretch 86 6.23 Bar Chart showing Crack details along the stretch 86 6.24 Bar Chart showing Potholes details along the stretch 87 6.25 Bar Chart showing Patchwork details along the stretch 87
LIST OF TABLES
TABLE
NO. TITLE
PAGE NO.
4.1 Equations for vehicle operating cost 44 4.2 Percentage of vehicles and growth rate 44 4.3 Equations for moisture correction factor 48 4.4 Equations for moisture correction factor 48 5.1 Data collected from 12th Mile to Kattankal of MDR-2 57
Chapter 1
INTRODUCTION
1.0 GENERAL
A comprehensive fully integrated Pavement Maintenance & Management Systems (PMMS) is the key to better reconstruction, restoration and maintenance decision-making of pavements. It weaves together information on all pavement inventories, condition and performance databases, and alternative investment options. An operating PMMS provides the road authorities the ability to better plan and manages highway, street, and road pavements. The Pavement Maintenance & Management Systems is a set of tools or methods that can assist decision makers in finding cost effective strategies for providing, evaluating, and maintaining pavements in a serviceable condition. It provides the information necessary to make these decisions. The PMMS consists of two basic components: A comprehensive database, which contains current and historical information on pavement condition, pavement structure, and traffic. The second component is a set of tools that allows us to determine existing and future pavement conditions, predict financial needs, and identify and prioritize pavement projects.
1.1 PAVEMENT MAINTENANCE & MANAGEMENT SYSTEM
According to the World Bank Report, “The developing countries have lost precious infrastructure worth billions of dollars through the deterioration of roads. The cost of restoring these roads is going to be three to five times greater than the bill would have been for timely and effectively maintenance. Vehicle operating cost rapidly outpaces the cost of road repair as the condition of road passes from good to fair to poor”. With several thousand vehicles per day moving on the highways, even a small saving in vehicle operation cost can justify very large investments on pavements.
Pavement Maintenance & Management Systems are useful tools in quantifying the overall maintenance needs of pavements and presenting the alternative maintenance strategies under budget constraints. The most important aspect of development of a PMMS is to collect, manage and analyse the pavement condition data in a considerably detailed format. Since geographical information systems (GIS), with their spatial analysis capabilities, match the geographical nature of the road networks, they are considered to
be the most appropriate tools to enhance pavement management operations, with features such as graphical display of pavement condition. The Pavement Maintenance & Management Systems is comprised of:
?? Storage, analysis and reporting software
?? Collection of stored pavement data
?? Maintenance and treatment costs
?? Data and formulas on pavement deterioration
?? Algorithms that calculate future needs and budget scenarios
1.2 FEATURES OF PMMS
A PMMS is any tool or process that helps a road agency to manage pavement in other words, any tool or process that helps an agency to maintain a network of safe and serviceable pavements in a cost-effective manner. When most agencies refer to the term “pavement management system,” they usually mean a computerized system where pavement condition information is stored, analyzed, and displayed.
1.3 PMMS INPUTS
At the heart of the pavement management system is the database, which is the storehouse for all pavement-related information collected. This database possesses several features, including: a large capacity, user friendly access, flexibility for future expansion, security features, and compatibility with other databases that store related information (such as bridge, congestion, and traffic crash data). Every piece of information in the database is referenced to the particular section of pavement (i.e., the particular intersection or segment of road) which it describes.
The information collected and stored in the database can be divided into five categories:
?? Inventory data,
?? Pavement history,
?? Construction data,
?? Traffic data,
?? Condition data (physical distress, roughness, structural capacity, friction),
1.4 ANALYTICAL TOOLS AND OUTPUTS
While the database is the “heart” of a pavement management system, data are not useful unless they are presented in a meaningful way. It is the role of analysis
procedures to transform the raw collected data into products such as charts, graphs, and reports that are helpful to decision-makers. A pavement management system can transform a spreadsheet containing pavement condition data into a map. A map can be quickly and easily used to examine the health of pavement in ways that are not readily apparent from columns of numbers. Analytic procedures are grouped into four categories:
?? Simple queries,
?? Pavement condition score calculations,
?? Remaining service life calculations, and
?? Strategy selection procedures.
1.5 STRUCTURE OF PMMS
Pavement Management in its broadest sense, encompasses all the activities involved in planning, design, construction, maintenance and rehabilitation of the of the pavement portion of public works program. The integration of both Attribute data and spatial data is made possible through GIS. The analysis of data is carried out through PMMA & GeoMedia analysis tools. This can be conceptually represented in fig 1.1
1.6 NEED FOR THE STUDY
In India, due to the large scale industrialization and commercial activities, there has been an unprecedented traffic growth during the last four decades. The high volume of vehicular traffic and increasingly heavy axle loads witnessed on Indian highways have brought the existing arterial road network to such a crippling stage that heavy investments are needed for restoring it to a desired serviceability level. This is a particular difficult situation, because pavements often are deteriorating faster than they are being corrected. Effective management of pavements is essential in these challenging times. Therefore, there is a need to link together explicitly the activities of planning, design, construction and maintenance of pavements.
The Road User Cost Study in India has established that due to improper maintenance and poor surface condition of road pavements, there is a considerable economic loss to the country due to increase in vehicle operation costs. If the road pavements are maintained to the desired level at an appropriate time, it is possible to save the losses in road user cost. In view of the budgetary constraints and the need for judicious spending of available resources, the maintenance planning and budgeting are required to be done based on scientific methods.
The whole life cycle cost analysis based on the road user cost relationships enables the decision makers to examine financial and economic implications of various options for formulating appropriate strategies for cost effective use of resources.
1.7 OBJECTIVES OF THE STUDY
?? Collection of relevant data for analysis.
?? To develop a digitised road map of Kozhikode district in GIS environment.
?? To assess the overall pavement condition based on functional and structural evaluation data.
?? Design of flexible pavement overlays.
?? To find the rate of progression of structural and functional deterioration.
?? To develop a plug-in software program for GeoMedia using Microsoft Visual Basic 6.0 environment,
?? To assess the impact of different maintenance strategies on the performance of pavement during the design period.
1.8 PROBLEMS, CHALLENGES AND THREATS
?? Lack of structural information regarding the thickness of the overlays, the maintenance method used, the type of bitumen used, or the construction quality.
?? Lack of knowledge about the exact age of pavement.
?? Lack of fixed evaluation segments for the condition and other surveys.
?? Increased rate of deterioration. (pavements deteriorate fast)
?? Overloading of vehicles. (no commitment with the legal loading)
?? Rapid traffic growth. (high increase of vehicle ownership )
?? Poor maintenance. (improper materials, wrong implementation, etc)
?? Improper design and implementation.
?? Limited resources (geometry, funds, equipment, materials, etc)
?? Insufficient information for decision-making.
?? Inefficient current traditional management system.
1.9 SCOPE OF THE STUDY
This work is an essential requirement for project planning and budget allocation. This work will help to reduce the effort needed than in conventional methods, to collect and analyse the data periodically by reducing the repeated works. The present work consists of the analysis and design of pavement data of Kozhikode District. The important aims of PMMS are:
?? An essential requirement for project planning and budget allocation.
?? Flexible pavement deterioration models include Deflection, Unevenness, and Present Serviceability Rating models representing structural condition and also functional condition model.
?? The performance and life of the Overlay has been assured on the basis of acceptable limits for deflection, UI and maintenance cost.
1.10 ORGANIZATION OF THE DISSERTATION WORK
The contents of the study are organized and presented in a chapter wise manner as follows:
Chapter 1: General introduction, need, objectives, scope of the study,
Chapter 2: Literature Review, general. Introduction, some definition, its basic
components are explained. Also planning activities are described in detail.
Chapter 3: Discusses the capability of the software, GeoMedia Professional
used for this work.
Chapter 4: In this chapter, About the Plug-in Software PMMA and the
methodology used were described.
Chapter 5: The inputs for the GPMMS, data entry methods and Dynamic
segmentation methods were discussed.
Chapter 6: The inputs for the GPMMS, Data entry methods and Dynamic
segmentation methods were discussed.
Chapter 7: Concludes the thesis by pointing at the limitations of the study and
scope for the further study.
1.11 CONCLUSIONS
This chapter gives a brief review about the basics of Pavement Maintenance & Management Systems. The objectives, scope, layout of the thesis were also explained.
Chapter 2
LITERATURE REVIEW
2.0 GENERAL
The purpose of this chapter is to review the available literature on Pavement management system, maintenance system and pavement management softwares and to discuss about the international PMS scenarios. An extensive literature survey was carried out to keep abreast with the latest development in the Pavement Management Systems. The work done both at the International level and domestic level is reviewed. Research work being carried out in various academic research institutions is also considered.
2.1 STATE - OF - THE – ART
Most highway agencies of the developed countries are now engaged in the development, implementation, and operation of pavement management systems. As early as 1980, five states in USA viz. Arizona, California, Idaho, Utah, and Washington were reported to be in various stages of development of systematic procedures for managing pavement networks on a project-by-project basis. AASHTO has had a significant role in furthering the development and use of Pavement Management Systems through the years. Federal Highway Administration (FHWA), the Transportation Research Board (TRB), and the National Cooperative Highway Research Programme (NCHRP) have contributed to major Technical studies. Notable among them is the NCHRP- Project 1-35 A, FY 1997 which was the basis for Guide for Pavement Management.
The “Guidelines for Pavement Management Systems,” published by AASHTO in July 1990, contains information needed for establishing a framework for a pavement management system. However, this document didn’t address the day-to-day issues encountered by pavement engineers or the issues associated with new and emerging technologies. Upon further research, a revised final report has been distributed to the members of the AASHTO Joint Task Force on Pavements and the AASHTO Highway Subcommittee on Design and has been approved for publication as AASHTO Guide for Pavement Management.
Universities and Research Institutes have developed research based Pavement Management System. Notable contributions are from Texas Transportation Research Institute (USA), Louisiana Transportation Research Centre (UK), University of Birmingham (UK) and Transport Research Laboratory (TRL, UK). Apart from these studies there had been a number of studies by Private Consulting Agencies as part of World Bank funded Highway Development projects in developing countries.
2.2 GLOBAL PMMS SCENARIO
In the early seventies, the phrase “Pavement Management System” began to be used by researchers to describe the entire range of activities involved in managing and maintaining pavements. At the same time, initial operational systems were also developed. Since then, the following factors have provided great impetus for growing interest in PMS development
?? Increasing budgetary constraints in relation to maintenance needs.
?? Recognition of direct effect of pavement condition on road user costs
?? Awareness of social and environmental values affected by road transport and road surface characteristics.
?? Advances in the development of pavement technology.
?? Increased capacity in pavement condition monitoring through advanced measuring equipment.
?? Advanced in computerization and information systems
?? General growth in awareness of management methods.
Presently, highway authorities in developed countries are using systematic and objective method to determine pavement condition and programming maintenance in response to observed conditions, as budget permits. In many of the developing countries, PMS is in various phase of working process with diversified approaches as per the respective needs and problems of each country.
2.2.1 United Stases of America
The concept of PMS took root in USA during the recent era of austere budgets. The first PMS model was developed by the Washington State Department of Highways in the mid seventies. This model consisted of development of performance prediction
model and a cost model based on a databank of information collected in Washington over a period of 6 to 8 years. Since then, various state departments of transportation have developed their own PMS methodologies suitable to their own needs and requirements. The Arizona Department of Transportation has reported savings to the tune of $2000 million over a period of five years as a consequence of successful implementation of PMS program to optimize pavement rehabilitation expenditure. The use of PMS at California Department of Transportation has resulted in improved communications between political and technical decision makers as regarding priority programming of pavement rehabilitation projects.
The Pavement Management System (called PMS-III) developed and implemented for the Ohio Department of Transportation (ODOT), is a network level system that can prescribe optimal maintenance and rehabilitation actions and the required budget for each year for a 6 year planning period. On the basis of present network condition and deterministic prediction model, PMS-III forecasts future network condition and rehabilitation needs and as associated budget. The optimal maintenance policies recommended by this pavement management system are based on maximizing the preservation of pavement investments for a given annual budget or on minimizing the cost of maintaining the network condition for a given performance level.
The State of Iowa has developed an Iowa Pavement Management Program (IPMP) to support both project level and network level PMS conducted by local and regional governments and the Iowa Department of Transportation. The PMS of Oklahoma Department of Transportation is characterized by the integration of a pavement performance - modeling tool with a new pavement network optimization model for identifying and selecting cost effective projects for maintenance and rehabilitation. The unique feature of this system is the integration of a pavement performance - modeling tool and a global optimization model for pavement network analysis. Pavement performance models can be updated whenever new data is available. All models can be evaluated and alternative models can be developed using the interactive modeling too. This system can produce satisfactory results for pavement engineers to perform pavement maintenance and rehabilitation planning up to 20 years. Flow chart shows the structure of the Pavement Management System implemented in the Oklahoma State.
Fig 2.1 Structure of the PMS implemented in the Oklahoma State 2.2.2 Canada
The Primary method of structural evaluation in Canada are deflection base e.g. Benkelman beam, Dynaflect and Falling Weight Deflectometer, with the latter becoming the primary device of choice and the former now seeing only very limited use. The indices commonly used are Riding Comfort Index (RCI), Structural Adequacy Index (SAl), Surface Distress Index (SDI), a composite measure Pavement Quality Index (PQI) and Pavement Condition Index (PCI), Performance prediction models commonly are for RCI, PQI, or PCI v/s pavements age, and are mainly developed through regression, Markov and Bayesian techniques.
Database Sufficiency Structural History Master Table Build Performance Model Setup
Distress Deducted Values Material Categories Treatments Performance Indices Grouping Variables Pavement Groups Performance Models Analyze Models Network Optimization Treatments Assigned to each pavement group for each year
Choose Best Scenario
Multiple Years Prioritization Treatments
Assigned to each pavement section for each year.
Generate / Modify Projects
Sections are aggregated in to
Fig 2.2 Framework of Canadian Pavement Management System 2.2.3 Australia
For a population of just over 20 million, Australia covers a very large landmass with an extensive network of roads, providing one of World’s road lengths per head of population. The Australian Road Research Board (ARRB) has been actively engaged in developing and promoting the adoption of PMS by road authorities to improve the efficiency of decision making and ensuring that maximum value is obtained from the funds allocated to road improvement. There are over 12 different PMS software packages available, which can cater for range of roads from National Highways to low volume rural roads.
2.2.4 United Kingdom
The United Kingdom Pavement Management System (UKPMS) has been designed to assist highway authorities in structural maintenance of pavements, It does so by improving both the systematic collection of information and the decision making process required to optimize resources and to generate a works program and the corresponding budget. UKPMS uses innovative technology to improve treatment selection and by optimizing the allocation of funds for various rehabilitation schemes.
A new generation pavement management system called HAPMS, for the National Roads of England has been developed by the Highways Agency, an executive body of the Department of Environment, Transport and the Regions (DETR) of the Central Government. The network of roads managed by the Highways Agency comprises only 4 per cent of the total road network of England, but carries 25 per cent of the total traffic. The applications working on this data are concerned with the presentation to all users of data in convenient format, including map backgrounds, the preparation and allocation of budgets and the determination of priorities for investment in major pavement maintenance. Fig. 2. 3 show the principal components of HAPMS.
2.2.5 France
The French Directorate of Road in association with LCPC (Central Public Works Laboratory) and the SETRA (Roads and Motorways Engineering Department) has developed a road management system, based on two complimentary suits of tools the VISAGE road database with its own facilities for the graphic representation of data and the GIRR package with its various data analysis modules. This system was implemented in 1992 by the state departments on the National Roads Network and extended more widely in 1996 to regional network also. The VISAGE AND GIRR software package as shown in Figure 2.4 use a rational approach for the management of pavement maintenance. It is an approach designed around four main stages; after an inventory on the nature of the road network, and an assessment of its condition, a maintenance policy must be defined and then applied through works programming. Finally, network follow - up is carried out on a regular basis to measure the effects of the policy put in place and, when applicable, to adopt the appropriate corrective actions.
Fig 2.4 Structure of VISAGE and GIRR 2.2.6 Germany
In Germany, there are 11000 km of motorways and 45000 km of federal roadways reported. To ensure that this road network is always functional for economy and society, a system was introduced in 1992, whereby the condition of the federal trunk roads is rated every three years. A road preservation management program called UMASTER has been developed with the objective of computations of the cost to the agencies responsible for financing road construction and preservation. But the road preservation program
includes only those types of conditions, which are relevant to medium and long range planning, and not those which require immediate attending e.g. filling of potholes. Funding needs are computed based on periodically performed surveys of roadway conditions and related predictions of the behavior of the future course of development of the condition of highway.
Methods have also been developed for forecasting the behavior of flexible pavements taking into account their conditions of use and climate influences, Quantitative forecasting model for the aspect of road conditions described as rut depth, water retention and network of cracks are in the process of development. On the basis of the condition rating and evaluation process ( called ZEB in German), a standard National Pavement Management System has been developed and applied by road construction authorities in 8 different states since January 1999. The Federal Ministry of Transport is now contemplating to extent this pavement management process to all 16 states. Tools now exist for the data required for a PMS, which can create a graphical representation of the data on plan and maps so that it is possible to get a quick overview of the road network condition.
2.2.7 Denmark
The Technical University of Denmark in cooperation with Dynatest Engineering developed the Dynatest Pavement Maintenance and Rehabilitation Management System (DPMS) during eighties. This system is capable of predicting future pavement condition for number of years on project as well as network level. It contains an optimization procedure to determine that combination of M&R measures that will ensure the optimal use of the budget. The system is not only based upon objectively measured functional and structural pavement characteristics, but it also ensures that the knowledge and experience of the local engineer is incorporated. The system ensures compatibility in all the steps of data flow, right from the collection of data out on the road to the final consequence analysis.
2.2.8 New Zealand
It was only in late 1998 that the Government of New Zealand decided to implement a National PMS. The initial objective was to have a completed preliminary system is place and integrated with the existing National Road Asset Management Program (RAMM). This consisted of a basis inventory and pavement condition database
along with an algorithm for selecting maintenance treatments. The new PMS has been build on the existing road management inventory system and the existing funding framework. The software package dTIMS (Deighton Total Infrastructure Management System) design total Infrastructure funding framework. The software package dTIMS along with a hybrid set of predictive models from HDM-II and HDM-4 has been adopted for the development of PMS would be used by over 70 different road - controlling authorities (city, district and state level) responsible for a network of more than 100,000 km of sealed and unsealed roads. Consultants engaged in management of the road networks would also use it.
2.2.9 Sweden
The Swedish PMS has been developed and implemented at several levels i.e, strategic level, programming level and Project level. The main objective of PMS at strategic level is to produce objective information as decision support in fund raising, in allocation of available budgets to the regions. The objective of PMS at programming level is to serve as a tool to identify candidate projects and the objective of the PMS at project level is to assist in planning and design of individual projects. Figure 2.5 shows the three levels of PMS along with three types of databases.
2.2.10 Austria
Increased road deterioration in Austria combined with the demand for a fair distribution of the available budgets urged the Australian Federal Road Administration to take necessary steps for the implementation of a nationwide PMS. A number of extensive studies by different investigators and improvements in administration ultimately paved the way for the start of very first application in practice of the Austrian Pavement Management System VIAPMS-AUSTRIA in late 1999. The Institute for Road Construction and Maintenance and Vienna University of Technology provided the road specific data and the practical use of VIAPMS analytical software. This PMS is the only available tool in Austria that underlined the necessity of allocating budget resources for pavement maintenance.
2.2.11 Indian Scenario
The absence of coordinated research has impaired the progress of developing an implementable PMS for India. Nevertheless there had been notable contributions from different research institutes and organizations like Central Road Research Institute (CRRI) (Updating Road User Cost Data URUCS 1991, Pavement Performance Study (PPS-EPS 1993), RITES (HDM Calibration Studies -1994), Bangalore University (Transition Probability Matrices for Optimal maintenance decisions-1995), & Indian Institute of Technology Kharagpur (Analytical Pavement Design (999). These studies laid the basis for the pavement data analysis and development of Pavement deterioration model for Indian roads. Apart from research institutes some private consultants have also tried to develop Pavement Management options in connection with some of the externally aided projects.
The PMS for National Highways funded by Asian Development Bank had been completed in 1995. Initially it was installed on a pilot basis in the states of Karnataka and Uttar Pradesh and at the National level in the ministry of Surface Transport. Another World Bank study was the 4 States PMS towards instituting a network level PMS in the States of Bihar, Maharashtra, Rajasthan and Uttar Pradesh. The study included a section of State Highways, Major District Roads and Other District Roads which are directly managed by States. The ARAN (Automated Road Analyzer) was used for the collection of pavement data. For the National Highways the PMS adopted is called NETTER-PMS and for the four states the PMS adopted is dTIMS (Deighton Total Infrastructure
Management System). The NETTER VOC model uses the Brazilian relationships from the World Bank HDM III model. The road deterioration and maintenance models for dTIMS had been established using HDM-III equations with adaptation for local conditions.
2.2.12 Studies at universities and Research Institutions
A brief review of the studies reported by various researchers is attempted in the following pages.
Dr. S S Jam, Dr. A K Gupta & Sanjeev Rastogi (1992) have made an attempt to analyze the data of nine test sections of overlaid flexible pavements located in the States of Uttar Pradesh and Himachal Pradesh. The data has been analyzed for pre-monsoon, post-monsoon and winter season for the years between 1980 to 1990. The performance and life of the overlays has been assessed on the basis of acceptable limits for deflection, rut depth, cracks and cracking pattern and maintenance cost. Models are also incorporated for the choice of type and thickness of materials for overlays on different sub grade soils economically without sacrificing the safety of road structure. Models developed in these studies are capable of predicting life of an overlay for given values of pavement thickness, overlay thickness, traffic intensity and acceptable limits for deflection, rut depth and cracking. The general model includes wide variation of climate, terrain, rainfall, temperature and thickness of overlay can be chosen economically.
Prof. (Dr.) S S Jam, Prof. (Dr.) A K Gupta, Prof. (Dr.) S K Khanna and Dayanand (1992) have studied the performance of twelve test sections of overlaid flexible pavement located in the states of Himachal Pradesh and Uttar Pradesh. The data has been analyzed for pre-monsoon and post monsoon seasons for the year 1994 for assessing the needs of corrective and strengthening measures and the pavement outputs with time has been presented using data from 1980 to 1993 from studies conducted at University of Roorkee. The influence parameter considered includes deflection, roughness, rutting, cracking and pot holes and the availability of resources for the choice of the type and thickness of materials for overlay and these parameters were recorded for the year 1993 and 1994 whose comparison showed the deterioration of flexible pavements with passage of time. The investment need for corrective measures were obtained and the investment strategy has been developed for maintenance and rehabilitation of flexible pavements. The conditions of the flexible pavements can be asserted by functional and structural
evaluations. The maintenance and rehabilitation need comes if any of the influencing parameters reaches its lowest acceptable limits, the overlays needs to be designed based on the cumulative number of standard axles rather than total number of commercial vehicles. Based on the requirements of corrective and strengthening measures, the investment estimation is done. Hence the study helps in taking decisions for maintenance and rehabilitation of flexible pavements rationally.
Maj. C R Ramesh, B P Nityananda, Y S Madvesh and Dr. C E G Justo (1994) conducted a study done jointly by Karnataka PWD and Department of Civil Engineering, Bangalore University on a stretch of cracked Cement Concrete pavement on Bangalore - Mysore State Highway to compute the relative performance of bituminous overlay with and without geo fabric at the interface. Installation of geo fabric at the interface between cracked CC pavement and bituminous overlay retards the propagation of reflection cracking and also there is a reduction in formation of new cracks on the overlay surface and a lower rate of increase in unevenness index. Geo fabric is a geo synthetic material like non-woven polypropylene fabric. A field study for ten years period using geo textile as stress-relieving interlayer has been reported to have given excellent results. In terms of service life treatment is likely to be economical. It is also desirable to vary the thickness of bituminous overlay with or without geo synthetic and to continue observation until failure of these overlays, for arriving at equivalency factors and also for comparison of cost on more realistic terms. Cost analyses of various alternatives are also done.
S. Chakrabarti, Ms Rawat and B Mondal (1995) have done the calibration of HDM-II and adaptation aspects of HDM Road Deterioration and Maintenance Effect (RDME) relationship for Indian conditions. The methodology for calibrations using pavement performance data, notably, the Pavement Performance Study (PPS) has been described. The deterioration factors have been derived for the pavement types and traffic loading levels appropriate for the country. The study claims that DDM RDME is robust, yet flexible enough to predict the deterioration for road in the country with the deterioration pavements factors very close to default values.
V K Sood and B M Sharma (1996) have reported the status of road network deficiencies in the present maintenance practices in our country. A pavement Performance Study was conducted with a view to develop data for total transportation
cost model for Indian conditions, to be achieved through development of pavement performance data to attempt development of layer equivalence and strength coefficients as feasible. Data was collected on the construction and maintenance inputs of different pavements based on studies carried out on nine pavement sections for a period of about 10 years. A brief description on various models such as cracking models, cracking progression models, ravelling models, pot holes models and roughness progression models have been included. Validations of models have been done based on limited fieldwork.
Turki I Al-Suleiman and Azm. S Al-Homoud (1996) have reported the work of evaluating the effects of pavement characteristics on pavement condition of the street network in Irbid City in Northern Jordan using the concept of Pavement Condition Index (PCI). It was found that 35.48 percent of the inspected pavement sections in Irbid City were in poor condition while 6.45 percent of the inspected pavement sections were in excellent condition. Alligator cracking, rutting, depression and swell distresses were found to be the most frequent distress types that caused the pavement deterioration. Pavement age, traffic level and pavement thickness were found to be highly significant and affect the pavement condition to great extent. Some of the asphalt mix properties such as air voids, bulk specific gravity and asphalt contents were found to have small effect on pavement condition. Pavement section of low air voids in the asphalt mix suffered from distortion and cracking due to the small resistance to compaction under traffic. Statistical models were developed to describe the relationship between PCI and pavement characteristics.
Mr. S C Sharma and R K Pandy (l997) made a study on the existing pavements completed in recent years presenting and extensive indigenous research back up and basic relationships to develop a total transportation cost model for Indian conditions. Indian research results have been used to develop this model and therefore, its predictions and results are considered truly reflective of Indian conditions. The model makes it possible to apply a rational approach in road maintenance decisions for obtaining best results from available funds including benefits of periodic maintenance, cost effectiveness of maintenance strategies etc.
Maj. Ramesh, Dr. A Veeraraghavan, R Sridhar, and Chandrasekhar S Pichika (1999)’ have collected an extensive field data develop the performance models and in the determinations of the life cycle cost. A computer program is developed to calculate the cost, first stage strengthening cost, user delay cost and salvage value. The program has the capability to compute the life cycle cost for any design period and for any number of sections by varying the threshold Present Serviceability Index Value which is on a scale of 1 to 10. The budget scenario can also be varied and the effect of budget level on pavement performance can be studied.
2.3 GIS TECHNOLOGY AND BENEFITS
A GIS is a computerized data base management system for accumulating, storage, retrieval, analysis and display of spatial (i.e. locationally defined) data. A GIS contains two broad classifications of information, geocoded spatial data and attribute data. Geocoded spatial data define objects that have an orientation and relationship in two or three-dimensional space. Attributes associated with a street segment might include its width, number of lanes, construction history, and pavement condition and traffic volumes. An accident record could contain fields for vehicle type, weather conditions, contributing circumstances and injuries. This attribute data is associated with a topologic object (point, line or polygon) that has a position somewhere on the surface of the earth. A well-designed GIS permits the integration of these data. The sophisticated database in a GIS has the ability to associate and manipulate diverse sets of spatially referenced data that have been geocoded to a common referencing system. The software can transform state plane coordinates and mile point data to latitude-longitude data and vice versa.
A GIS can expand the decision making on repair strategies and project scheduling by incorporating such diverse data as accident histories, economic needs hazardous materials shipment and vehicle volumes. A GIS can perform geographic queries in a straightforward, intuitive fashion rather than being limited to textual queries; A GPMMS can be used to build projects through spatial selection, can compute traffic impacts of various PMS plans and can incorporate the results of life cycle forecasts into measurements of future mobility.
The network-level PMS has been integrated with GIS for the selected highway network. The input data and results obtained under life-cycle cost analysis of the highway
network have been used to demonstrate the use of GIS in enhancing the pavement management system. The commercially available GIS software GeoMedia has been used for this purpose. A spatial map of the study area has been created, which is comprised of various GIS themes such as national highways, pavement sections, section nodes and districts. The input data and the results of the life-cycle cost analysis of highway network have been imported into GIS as attributes of the pavement sections. GIS has been used to enhance pavement management information with its typical features, such as graphical display of highway network and current and future pavement condition of the selected pavement sections. GIS also provides an excellent spatial query and analysis capability to select the candidate pavement sections in need of immediate maintenance.
Fig 2.6 Inputs – Analysis – Output - Chart 2.4 INFORMATION TECHNOLOGY FOR PMMS
Pavement Performance Forecasting, Optimization & Simulation
Historical Pavement distress condition Where, when, what to treat Pavement Performance Forecasting, Optimization and Simulation models INPUT 4. Future pavement
performance visualization and
spatial analysis
Optimization models Simulation models Deterioration models
GIS mapping, visualization and spatial analysis Historical traffic
condition
Given funding Forecasting time frame
(5 or 10 year later) Treatment Determination
2. Funding balance among
congressional districts
OUTPUT
1. Avg. statewide composite future performance index
3. Workload balance among
For performing GIS based Pavement Maintenance & Management Analysis, there are so many softwares used world wide. Among them the leading PMS software’s in practice are:
RoadSoft
RoadSoft, available from the Local Technical Assistance Program (LTAP) at Michigan Technological University, is a GIS-based roadway management system. The software package was developed for local road agencies within Michigan and engineers and managers to analyze roadway information within their jurisdictions. The software uses the Michigan Accident Location Index (MALI) as a physical reference base.
RoadSoft has a road surface inventory module for rating pavement condition using the PASER (Pavement Surface Evaluation and Rating) system. PASER is a simple method of rating asphalt, concrete, and gravel roads developed by the University of Wisconsin’s Transportation Information Center. Manuals filled with pictures detail a one-to-10 evaluation system in which "10" means excellent while "one" indicates a failed road. This system is used to obtain consistent ratings based on the types of wear evident on the roadway surface, such as cracks and deformations. Based on the types of defects, general characteris tics of the roadway, and age of the pavement, PASER makes recommendations for the types of fixes that would be appropriate for the road. There are rating manuals available for concrete, asphalt, and gravel roads.
MicroPAVER
MicroPAVER is a pavement management system developed by the U.S. Army Construction Engineering Research Laboratory and distributed by the Technical Assistance Center at the University of Illinois at Urbana-Champaign. The software contains a full-featured PMS, including manuals for evaluating pavement conditions. MicroPAVER is a decision-support tool, allowing agencies to systematically determine maintenance and repair needs and priorities. The system also enables users to compare budget scenarios and their effect on pavement networks, and data can be linked to a GIS.
Inspection data from the road network is input into the system’s database. By taking samples of a section of the entire network, MicroPAVER can calculate the Pavement Condition Index (PCI). Information from the PCI is used to accurately predict the overall health of the pavement network. Using pavement life cycle models in the
software, this system can quickly determine which pavements need attention the most, and also calculate the critical condition pavements. (Critical condition pavements are those that are close to the point where they deteriorate rapidly.)
HDM - 4
The internationally recognised Highway Development and Management System (HDM-4) have been used to develop this PMS. Since the size of the highway network is not very large and the analysis period is of medium duration, the ‘programme analysis’ application of HDM-4 has been used for the network-level pavement management analysis. The results obtained through the network-level pavement management analysis have been presented through various applications of GIS.4 This helps in easy identification of the candidate pavement sections, due for maintenance during the analysis period, and the associated details of timing, type and cost of maintenance activities can also be readily determined.
GeoPave
GeoPave can extract and display information that a Pavement Manager requires. It has Dynamic GIS link to your MTC-PMS system. Easy to use menu selections. Also it has Plug-in extension to ArcView / ArcMap.
The main features of GeoPave are, it can maintain a good Pavement History, it can analyse Maintenance & Rehabilitation Workplans. It can also directly account for Funding Scenarios.
Stantec PMS
Stantec developed a Pavement Management Application (PMA) within their Infrastructure Management System (IMA) software. The Infrastructure Management Application is a tool for the management and graphical display of asset information, structural condition, and other available data for municipal utilities and right-of-way assets, either individually or as a group. IMA is a network planning tool for municipal assets.
Physical characteristics, structural condition assessment, and rehabilitation program development for each asset can be objectively compared with the entire network for planning and rehabilitation and maintenance programs. Information can be analyzed
graphically, or through the use of a GIS. A rehabilitation module analyzes road condition to prioritize rehabilitation activities and budget programming. The system can also recommend maintenance activities, such as crack sealing and pothole patching.
Hansen PMS
Hansen develops asset management software for both the public and private sector. Hansen developed a pavement management system to complement the infrastructure management software developed to assist agencies maintain assets under their control.
The pavement management system is completely customizable by the user. Working with consultants from the company, the management system is tailored to meet the needs of the user. Hansen works with the agency to determine which inputs are needed to perform analysis, fits the deterioration curves to inputs, and calculates outputs.
CarteGraph PavementView
PavementView pavement management software, developed by CarteGraph Systems, is part of their more general infrastructure management products. Based on concepts introduced by the Federal Highway Administration and the U.S. Army Corps of Engineers, this system integrates data collection, inspection records, asset history, along with performance modeling to accurately assess current and future pavement condition.
PavementView is able to graphically display pavement performance using maps, graphs, or charts. This system allows users to develop queries and reports using all database fields. Users can generate standard or custom reports to assess inventory condition and help manage scheduled and completed
2.5 CONCLUSION
A brief review of the available literature on Pavement management system, Pavement maintenance system and pavement management softwares were done. The international PMS scenario was also discussed.
Chapter 3
A BRIEF REVIEW OF GeoMedia
3.0 GENERAL
This chapter gives a brief description about various functions and tools available in GeoMedia 5.2 as well as GeoMedia Transportation Manager 5.2.
3.1 GEOMEDIA PROFESSIONAL
GeoMedia Professional is a fully functional desktop GIS solution. Based on Jupiter technology from Intergraph Corporation, this product is an enterprise GIS for the Windows 2000, Windows NT and Windows XP operating systems. Using GeoMedia Professional we can make live connections to geospatial data in multiple data warehouses simultaneously; analyse data relationships; turn information into precise, finished maps for distribution and presentation; and put geospatial data into the hands of users. GeoMedia’s extensive object model is accessible for customization through industry-standard programming languages such as Microsoft Visual Basic, Microsoft Visual C++, PowerBuilder, and Delphi.
Some of the important terminologies associated with GeoMedia are given below.
3.1.1 GeoWorkspace
A GeoWorkspace is the container for all our work. Within its confines are the warehouse connections to our data, map windows, data windows, toolbars, coordinate-system information, and queries we have built. The first thing we have to do is to open an existing GeoWorkspace or create a new one. Once we are in a GeoWorkspace, we can change its coordinate system, establish warehouse connections, run queries, display data, and perform spatial analyses. The settings and connections we define in a GeoWorkspace are saved in a .gws file, although the actual data remains stored in the warehouse. Every GeoWorkspace is built on a template, and we can create our own templates or use an existing one. The software is delivered with a default GeoWorkspace template, normal.gwt, which contains an empty map window, an empty legend, and a predefined
coordinate system. Opening an existing GeoWorkspace may take a long time. The amount of time varies with the number of feature classes being loaded into displays, the amount of data per feature class, and the processing time of any queries. To improve performance, we can delay the loading of data by selecting the ‘Do not load data when opening GeoWorkspace’ check box on the General tab of the Options dialog box.
3.1.2 Co-Ordinate System
A coordinate system provides the mathematical basis for relating the features in our study area to their real-world positions. The software supports the following types of coordinate systems:
?? ?A geographic coordinate system (the default) references a spheroid, expressing coordinates as longitude, latitude, where longitude is the angular distance from a prime meridian, and latitude is the angular distance from the equator.
?? ?A projected coordinate system references a projection plane that has a well-known relationship to a spheroid, expressing coordinates as X,Y, where X normally points east on the plane of the map, and Y points north at the point chosen for the origin of the map. The X coordinate called easting, and the Y coordinate is called northing.
?? A geocentric coordinate system references an earth-centred Cartesian system, expressing coordinates as defining the position of a specific point with respect to the centre of the earth. These coordinates are Cartesian (X, Y, Z) where the X axis of the geocentric system passes through the intersection of the prime meridian and the equator, the Y axis passes through the intersection of the equator with 90 degrees East, and the Z axis corresponds with the earth’s polar axis. The X and Y-axes are positive pointing outwards, while the Z axis is positive towards the North Pole.
Each feature class stored in a warehouse can have its own unique coordinate system. If we change the co-ordinate system after displaying data, the data is transformed to the new co-ordinate system, and the display is updated. Changing the co-ordinate system in the GeoWorkspace does not affect the data in the warehouse, only data in the map window. Finally, co-ordinate systems are heavily data dependant; therefore, one
should not define them arbitrarily. To be displayed accurately in a GeoWorkspace, all data must specify a ordinate system. To accommodate data with no specified co-ordinate system, we must first define a co-co-ordinate system file (.csf) outside of the software.
3.1.3 Warehouse
Warehouse is considered as the source of both graphic and non-graphic information. We can display feature geometries and attribute data in a GeoWorkspace through connections to warehouses where the data are stored. Each warehouse connection uses a data server to convert the data into a format that the software can display. All warehouse types are read-only, except for Access, Oracle, and SQL Server. This protects the integrity of our source data. So, if we want only to display data in the software from one or more warehouses, we can simply create one or more warehouse connections and then use map window and data window to display the data.
3.1.4 Windows
The GeoMedia GeoWorkspace can contain one or more windows—map window, data window, and a layout window. These windows provide us with different ways of visualizing our data. The map window shows graphic display or features. The data window shows the same features in attribute form, that is, non-graphic data associated with the geographic objects. Thus, if a feature is displayed in multiple map and data window, it highlights in all when selected. The window allows you to design and to plot a map layout. Map graphics in the layout window can be optionally linked to reflect changes made in the map window, or they can be a static snapshot reflecting the characteristics of the map window at the time of placement. Each map window contains the following marginalia items: a legend, a north arrow, and a scale bar.
3.1.5 Legend
The legend contains the following parts:
?? ?A title bar, which we can turn on or off. The title bar must be turned on before we dismiss the legend.
?? ?Legend entries, which we use to control the display of the objects in the active map window. Legend entries can have titles, subtitles, and headings.
The legend contains a separate entry for each map object. When a feature class or query has multiple geometry or text attributes, a separate entry is added to the legend for each of these attributes. An example of a legend is shown in Fig 3.1.
Fig 3.1 A Legend
Each entry contains a title and a style key. If statistics for a legend are turned on, the entry displays the count of map objects in parentheses next to the title. Style keys for feature classes and queries are dynamic and represent the geometry type of the feature class (point, line, area, or compound). Style keys for thematic displays, images, and text are static and represent the object type. The various feature classes and their style keys appearing in the legend are shown in Fig 3.2 and Fig 3.3. Style keys include the following:
Fig 3.2 Style Keys representing feature classes in Legend
Style keys can also indicate the state of the following legend entries:
Fig 3.3 Style Keys representing errors in Legend
We can add the following types of map objects as entries to the legend:
?? ?Feature classes
?? ?Queries
?? ?Thematic displays
?? ?Raster images
3.1.6 Feature and Feature Class
A feature is represented in a map window by geometry and is further defined by non-graphic attributes in the database. The values of these non-graphic attributes can be viewed as cells in the data window view on the non-spatial data of the feature. In a read/write warehouse, we can create a new feature class, delete a feature class, and edit a
feature class definition. We can edit a feature class in the following ways: by adding attributes, by removing attributes or ?by changing attributes
In a read/write warehouse, we can also manage feature data in the following ways: by changing attribute values??by adding or deleting features.
Geometry refers to the graphic representation of a feature in the map window. The following geometry types represent features:
?? A point feature is represented by one or more points on a map that represent the location of a feature. A point can also represent features that cannot be mapped at the defined map scale. Elevation control points, buildings, and manholes are all examples of point features.
A linear feature is represented by one or more lines and/or arcs. Rivers, railroad tracks, utility lines, and roads are examples of linear features.
An area feature is represented by closed boundaries. Counties, land parcels and water bodies are examples of area features.
A compound feature may have point, linear, and/or area geometry within the feature class or even within a single feature.
A text feature is represented by text that appears at a point location on a map. You can place text in an existing text feature class or create a new one to contain it. Text can have an orientation, that is, it can be rotated.
An image feature is a raster image.
A feature class is the classification in which each instance of feature is assigned. The software allows creating feature classes in three ways: from scratch, by copying some of the information from an existing feature class into a new feature class in the same warehouse, and by attaching an external data source.
