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RHD Operational Procedure Planning and Maintenance Wing
 
HDM - Database Division
 
OP/HDM/2.2 - GIS Development and Maintenance
 
Purpose and Scope :

The purpose of this procedure is to assist RHD develop, use and maintain the RHD GIS system. This GIS system is now well established and has been operating successfully with the necessary data, software and hardware. This operational procedure includes future development and the long-term maintenance of the RHD GIS system.
 
Definitions :

GIS: Geographical Information System is defined as an information system that is used to input, store, retrieve, manipulate, analyse and output geographically referenced data or geo-spatial data, in order to support decision making for planning and management of land use, natural resources, environment, transportation, urban facilities, and other administrative records.

RMMS: Road Maintenance and Management System, is a database which contains the available information for the RHD Road Network.
 
Responsibility :

Superintending Engineer HDM Circle - will be able to deal with GIS management and policy strategies, and be able to co-ordinate RHD decision-makers.

Executive Engineer - Database Division - overall supervision of GIS development, GIS budgeting, report and document preparation. Co-ordinate GIS development with RMMS database development
 
Method :

GIS has an important role in integrating RHD road features along with related tabular information captured and developed in the RHD database and MIS. All sections/wings/offices within RHD require up to date road maps. The Database division now provides a centralised mapping facility within RHD.

4.1 FUTURE DEVELOPMENT

To ensure an up-to-date RHD GIS system there will continue to be opportunities to make further expansion and more flexible use of GIS mapping in RHD. New Ideas, expansion of functionality, advanced development could be adopted for future development.

Expansion of the GIS would include a set of steps starting with the needs assessment and review of the on-going use and maintenance of the GIS system, as follows:

Needs Assessment & Conceptual Design

Review existing data & Conduct new survey if necessary

Review existing Hardware and Software capability

Database Planning and Design & Database Construction

Pilot Study/Test with the existing system with the existing system

GIS Application Development

GIS Use and Maintenance

The component of the future plan could address the following issues:

Ensure that descriptions of applications are understandable to the user

A logical translation of user requirements to system specifications

Detailed specification suitable for system development

4.2 GIS USE AND MAINTENANCE

For GIS ongoing operation and maintenance two broad tasks are required: User support and service and System maintenance (database, hardware and software).

4.2.1 USER SUPPORT AND SERVICES

The following user support services can be identified for implementation of the RHD GIS:

Technical support while GIS is fully utilised. This will include for GIS data and application, software and hardware.

User feedback to identify system enhancements (GIS functions/applications and database)

Data error/problem reporting and resolution procedures

User feedback on data accuracy and system performance

User involvement in decisions on all system upgrades (data, software, and hardware)

User training courses as needed (GIS application and software, databases and spatial analysis, e.g. specific application use)

RHD GIS System and Database maintenance

Three driving components of system update can be identified in the implementation of GIS, which are:

System Enhancement (e.g. enhanced functionality)

Database expansion (e.g. widen scope of spatial and tabular data employed in GIS system)

Routine system maintenance (application updates)

Regular review (e.g. annual) should assess these and the benefits and the associative cost of any update. As user can be negatively affected by the changes, major enhancements or expansions need to be subjected to provide training courses to the users.

4.2.2 DATA MAINTENANCE PROCEDURES

1) Managing existing data

Backup/Restore

An available backup system is necessary for the GIS database. Should anything happen in the hardware system (i.e. the file server disk crashes), EE Database will then be able to restore previous backup without loosing the data. Therefore, a schedule for regular backup for the system is required. This will be part of network maintenance (see OP/ME/2.2).

Granting Access to data

Some RHD GIS applications allow user to display and/or analyse the data without changing or editing. Read only access to the GIS data should be given to this type of users. In this way only supervisor or trained technicians will be granted full read and write permissions to the data. The GIS manager should be responsible for granting data read/write permissions to users.

Another important function in data maintenance is to consider transaction maintenance. This type of application registers items in the database such as when a record was updated, by whom, and from what source the changes came from. A history log is kept on each record and old records being updated can be sent to an archive file. This step may seem unnecessary in the beginning, but as the database enlarges an application such as this will be of great value.

2) Reviewing current data for potential error and Changes

A standard Quality Control (QC) system should be implemented. This should determine what will be checked and what degree of accuracy will be required for RHD GIS. Outline guidance is provided as follows:

Incompleteness of data

Any incomplete GIS features and tabular data should be identified. This should start by checking that all the required GIS layers and the associated tabular information in the database are included and correctly referenced. For example, a Road link should have a complete set of information such as Road Number, Link Number, Start and End Location and Lengths. Checking should be done for the completeness of each geo-feature in the database and then each feature is assigned the correct layer and indexed consistently throughout all GIS maps.

Errors in GIS data

Two types of errors could be encountered: Positional and Attribute. Positional errors are either absolute or relative. Relative accuracy can be measured for the maximum deviation of the interval between two objects on a map and the corresponding interval between the actual objects in the field.

Topological Error

Building the right feature topology is important. Once GIS topology has been defined successfully, other spatial information such as Arc length, polygon area and perimeter lengths may be determined from the GIS database automatically. Therefore, building accurate topology for each feature type is the important for the GIS database development.

3) Detecting Changes and Identifying Sources for Updates

As RHD is a Highway Agency, several internal sources of data updating can be identified such as a new inclusion of a road link in the network, new road construction or changing the class definition of a road. All these changes of data/information should be identified and spatial changes updated in the RHD GIS accordingly.

4) Collection of new Information

When new pieces or sets of information need to be collected and entered into GIS, data collection should be clearly defined. Data collection from other sources is expensive; it requires more labour to make usable in the system. Data quality and standard should be identified for receiving data from outside RHD. Data collection from field by GIS staff is more reliable and more accurate. If good data collection methods and procedures are used.

For example, for a new road inclusion into RHD network, GPS alignment survey can be used. This may be more accurate and cheaper than of other data collection.

5) Applying edits and Tracking changes

Editing the database can become a tedious task. However, it is important to the data integrity that the edits are done accurately and consistently. All changes should be tracked in a way, as described above, that will allow GIS Specialist to determine when the records were updated, by whom, and what level of confidence the data was rated.

6) Verifying corrections

Develop a QC process or use procedures to check the corrections. The GIS Specialist will be able to monitor to verify every change and possibly could select a random number of records and confirm that corrections were made correctly.

7) Updating master database

Once edits are made and verified that they were updated correctly in the GIS database, the master database should be updated and should be documented accordingly.

8) Distributing updates to user

All the amendments and the changes of data should be documented and should be circulated among its potential users. Meta-Data documentation having updated information should be published in RHD Website to ensure that all changes were informed to the users.
 
References :

Fischer, Manfred M. and Nijkamp, Peter, "Geographic Information System, Spatial Modelling, and Policy Evaluation," Berlin & New York: Springer-Verlag, 1993, pg. 42.

Abler, R.F., 1987, "The National Science Foundation National Center for Geographic Information and Analysis" International Journal of Geographical Information Systems, 1, no. 4, 303-326.

Montgomery, Glenn E. and Harold C. Schuch, GIS Data Conversion Handbook, GIS World, Inc. and UGC Consulting, Fort Collins, 1993.

Development of a Geographic Information System (GIS), June 1995
 
Procedure Flowchart :

None.
 


 


 

 

For duties associated with each grade of personnel see

 

Updated on : 1/12/2003

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