SDLC

1. SUG 653 GIS II
Chapter 1:
System Development Life Cycle (SDLC)
1. System Development Team:
- GIS Manager
- GIS Analyst
a. Technology assessment
b. Software development
c. Data development

2. How to Be An Efficient GIS Manager
• A good GIS manager ensures that:
a. A good system is selected.
b. The system works efficiently.
c. It contributes to the organisations strategic
objectives.
d. It is sustainable.
• Aware the consequences of failure are severe for
you and other GIS users.
• Success demands sharing experience and
knowledge with others.

3. System Defined
• A system is a set of:
– Interrelated components.
– Working together.
– For a common purpose.

4. • A Generic System Model
(with Six Components)
1.Boundary
2.Inputs
3.Outputs
4.Processing
5.Controls
6.Feedback

5. 1. Information System defined
• An Information System is:
• a type of fabricated system
• used by one or more persons
• to help them accomplish some task or assignment they
• Have
2. An Information System:
• supports policies & procedures
• has three components - data, people, procedures - in
• addition to the six general system components- (i.e.
• input, output, processing, control, feedback and
• boundary)

6. • Information Systems
• Information systems are the support
structure for meeting the company’s
strategies and goals
• Information systems help knowledge
workers perform their jobs

7. • Automated Information System
• An Automated Information System is:
a. a type of fabricated system
b. used by one or more persons
c. to help them accomplish some task or assignment
they have
d. Utilizes hardware and software
• An Automated Information System has three basic
characteristics to consider:
a. DATA - input, output, or already stored electronically
b. FUNCTIONS - transformations or actions taken
c. BEHAVIOR - the observable effects from interaction

8. GIS
• A GIS is a computer application that
stores, retrieves, manipulates, analyzes, and
displays geographically referenced information or
geospatial data.
• Components of GIS
1. People – the user of the system
2. Applications – the process and programs they
use to do their work
3. Data – the information needed to support those
applications
4. Software – the core GIS software
5. Hardware – the physical components on which
the system runs

9. Systems Development Life Cycle
(SDLC)
• All systems have a life cycle or a series of
stages they naturally undergo.
• Information systems are developed using the
systems development life cycle.
• It is so called systems development life cycle
(SDLC) because the development processes
are derived from the system’s life cycle.

10. • Systems development life cycle (SDLC) is a
structured step-by-step approach for
developing information systems. It is a
methodology that partitions the system
development process into formal
stages/phases that must be completed
sequentially with a very formal division of labor
between end users and information system
specialists.

11. SDLC – What can we say about it
• It provides a framework to organize a large number of
activities that the development process incorporates
• It is usually divided into phases and each phase
consists
of activities
• The phases are usually presented as a sequential set
with each phase ending with a set of deliverables
• There are a number of life-cycle approaches available:
Predictive approach (e.g. Waterfall model) , Adaptive
approach (e.g. Spiral model)
• Each approach has its own terminology even though
they all strive to present the same information

12. Phases in SDLC
• The number and name of the phase in a SDLC
varies.
• The phase can range between 4 to 8 or more
stages,
but the primary phases are
1. Planning (just after Conception)
2. Analysis
3. Design
4. Implementation
5. Maintenance (starting Maturity)
• Each culminating in a deliverable, either a
written
document or a piece of software (or both)

13. Model of a SDLC

14. Activities in Each Phase
• Project planning – initiate, ensure
feasibility, plan schedule, obtain approval for
project
• Analysis – understand business needs and
processing requirements
• Design – define solution system based on
requirements and analysis decisions
• Implementation – construct, test, train
users, and install new system
• Maintenance – keep system running and
improve

15. Models
1.Models
• Representation of an important aspect of real
world, but
not same as real thing
• Models come in many forms
- Physical analogs, mathematical, graphical
• Abstraction used to separate out aspect. System
development models are highly abstract
- Depict
inputs, outputs, processes, data, objects, interact
ions, locations, networks, and devices
• PERT or Gantt charts: model project itself

16. Approaches to SDLC
• Two main approaches to SDLC
1. Predictive approach – assumes project can
be planned out in advance
2. Adaptive approach – more flexible,
assumes project cannot be planned out in
advance
• All projects use some variations of SDLC

17. The Traditional Predictive SDLC
Approaches
1. Pure waterfall approach (predictive SDLC)
• Assumes project phases can be sequentially executed
• System development progresses in a straight line
fashion
• Project drops over the “waterfall” into the next phase
2. Modified waterfall approach
• Tempers pure waterfall by recognizing phase overlap
• Informs many current projects and company systems

18. What makes Systems
DEVELOPMENT a difficult activity?
• Initially, problem domains (areas) tend to have
poorly defined boundaries
• Problem domain solutions are artificial
• Problem domains are dynamic
• Problem domain solutions usually require
interdisciplinary knowledge and skills
• Systems Analyst’s knowledgebase is continually
expanding
• Systems Analysis and Design is a highly cognitive
activity
• Working with people