9. Swift

  • 9.34. Swift method

    Swift methods are functions associated with certain types In Objective-C, a class is the only type that can define a metho...
    2025-10-25 13:33:52 UTC
  • 9.35. Swift subscript script

    Subscript scripts can be defined in Class, structure, and enumeration targets and can be thought of as shortcuts to access o...
    2025-10-25 13:33:49 UTC
  • 9.36. Swift inheritance

    Inheritance can be understood as one class getting the methods and properties of another class. When a class inherits othe...
    2025-10-25 13:33:51 UTC
  • 9.37. Swift construction process

    The construction process is a preparation process for using an instance of aclass, structure, or enumerated type. This proce...
    2025-10-25 13:33:49 UTC
  • 9.38. Swift destructing process

    The destructor is called immediately before an instance of a class is released. Use keywords deinit to mark the destruct...
    2025-10-25 13:33:49 UTC
  • 9.39. Swift optional chain

    An optional chain is a process that can request and invoke properties, methods, and subscripts, and the target for a request...
    2025-10-25 13:33:50 UTC
  • 9.40. Swift automatic reference count (ARC)

    Swift uses automatic reference counting (ARC) to track and manage application memory Usually we don’t need to free memory ...
    2025-10-25 13:33:46 UTC
  • 9.41. Swift type conversion

    Swift language type conversion can determine the type of instance. It can also be used to detect whether an instance type be...
    2025-10-25 13:33:44 UTC
  • 9.42. Swift extension

    An extension is to add new functionality to an existing class, structure, orenumerated type. An extension can add new func...
    2025-10-25 13:33:46 UTC
  • 9.43. Swift protocol

    The protocol specifies the methods and properties necessary to implement a particular function. Any type that meets the re...
    2025-10-25 13:33:50 UTC
  • 9.44. Swift generics

    Swift provides generics that allow you to write flexible and reusable functions and types. The Swift standard library is b...
    2025-10-25 13:33:50 UTC
  • 9.45. Swift access control

    Access control can limit the level of access to your code from other source files or modules. You can explicitly set acces...
    2025-10-25 13:33:46 UTC
《地理信息系统原理、技术与方法》  97

最近几年来,地理信息系统无论是在理论上还是应用上都处在一个飞速发展的阶段。 GIS被应用于多个领域的建模和决策支持,如城市管理、区划、环境整治等等,地理信息成为信息时代重要的组成部分之一; “数字地球”概念的提出,更进一步推动了作为其技术支撑的GIS的发展。 与此同时,一些学者致力于相关的理论研究,如空间感知、空间数据误差、空间关系的形式化等等。 这恰好说明了地理信息系统作为应用技术和学科的两个方面,并且这两个方面构成了相互促进的发展过程。