Chapter 15 GIS Design and Implementation Management Information Systems –Systems Analysis –Systems Design –Systems Implementation

The role of the institutional setting Avoiding duplication of data Designing to fit the expectations of management and end users

The requirement that the GIS meet user needs Defining need by the tasks of the users Defining the capabilities of the user to handle the software

The system development life cycle Define the activities of the project and the order of them Assure consistency in life cycle stages across projects Provide decision points for management at various phase points

System development or “waterfall model” A linear and cascading model Not easily open to changes and therefore iterations of process

Processes System requirements - needs analysis Feasibility analysis - added phase Software requirements Analysis Program design Coding Testing Implementation and operations

The “Mythical Man Month” What does it mean? A means of estimating project cost One error in the first step costs ten to 100 times more in the later step Throwing manpower at a problem seldom solves it Not the same as picking cotton … linked and sequential tasks No system works perfectly the first time. Expect projects to take longer than originally estimated

General Systems Characteristics Large systems require more resources Large systems can often be broken down into smaller subsystems The system will tend to grow and adapt Successful systems grow at a greater rate

The system development life cycle Needs assessment … How done? –Who defines need? Consultant? Manager End User … what if the end user does not understand the capabilities

System development life cycle (cont) Feasibility study … constraints on the system –Economic - “cost / benefit analysis” –Technological - “does the technology exist” –Economic - “how do we pay for this” –Organizational - “ can our staff handle this?” –Legal … “can we do this legally?”

Systems development life cycle (cont). Software design versus system design –Software design Programming … software company Custom design … “Avenue … AML… etc” Often limited to what the canned packages can do

System development life cycle (cont) Systems design –Analysis of the day to day tasks –Analysis of desirable new tasks Definition of design characteristics by output need Define the activities of the project and the order of performance Assure consistency among many projects - no duplication Provide decision points for management

A Structured Design Model The Initial View - Examination of System Feasibility The Conceptual View.. Requirements determination and data base design The Detailed View … Mapping to a specific GIS –database construction and application construction System Implementation

Views of the Systems Local Views … –Decision System Matrix –View Integration

Formal Design Methodology Spiral GIS Design Model.. P 439 Figure 15.6 p. 440 Defining spatial information products (SIPS) –Ascertain from clients what the product should look like Example? –Local user views integrated to a larger global view County example?

Implementation and Operations Day to day activities –Constant data update ????? –Training –Structured reporting –Ad Hoc data output The critical cost here is what?