What are the types of gis application models? What are their characteristics?

1, waterfall model: when the user needs change, the process is irreversible from top to bottom. (Requirements, Analysis, Design, Implementation, Testing)

2. Unified Development Process (USDP): This is an iterative and incremental development process;

Every iteration will get closer and closer to the final goal.

Advantages of this method: the change of requirements in the process will not affect the development of the whole project, and the project control is more flexible.

Reduce costs;

It is convenient to better maintain the project schedule;

Promote the cooperative development of the team;

It is convenient to adapt to the dynamic changes of user needs.