The link between Java and GIS

The link between Java and GIS

Geographic Information System (GIS) is a new frontier subject developed in the early 70.
because GIS has powerful and unique functions in data acquisition and input, spatial data management, map extraction, automatic mapping, digital terrain analysis, data output and so on, it is in resource inventory and management, regional town planning, disaster prevention and monitoring, environmental protection and evaluation, Land management and real estate management, macro-decision-making and other fields related to spatial information has been widely used, and has achieved good social and economic benefits.
In recent years, with the development of networked technology and the proposed digital Earth, GIS is pressing for the development of network direction. Although some of the existing GIS software support network functions more or less, the real network GIS does not appear, which means that the GIS software which can browse and operate directly on the Web browser has not appeared. It has become a hotspot in GIS field to study GIS suitable for network. So in the GIS development, there is the advent of Java.
Java is an object-oriented programming language that can compose cross-platform applications, and is a generic term for Java programming languages and Java platforms.
the Java language is simple . The syntax of the Java language is close to the C and C + + languages, making it easy for most programmers to learn and use Java. Java, on the other hand, discards features that are seldom used in C + +, which are difficult to understand and confusing, such as operator overloading, multiple inheritance, and automatic coercion of type conversions.  In particular, the Java language does not use pointers and provides automatic scrap collection, which makes it unnecessary for programmers to worry about memory management.
the Java language is object-oriented . The Java language provides primitives such as classes, interfaces, and inheritance, and for simplicity, only supports single inheritance between classes, but supports multiple inheritance between interfaces, and supports the implementation mechanism between classes and interfaces. The Java language fully supports dynamic binding.  In short, the Java language is a purely object-oriented programming language.
the Java language is distributed . The Java language supports the development of Internet applications and has a network application programming interface (Java net) in the basic Java application programming interface, which provides a class library for network application programming.  The RMI (remote method Activation) Mechanism of Java is also an important tool for developing distributed applications.
the Java language is robust . Java's strong typing mechanism, exception handling, and automatic collection of scrap are important guarantees of Java program robustness. Discarding pointers is a wise choice for Java.  Java's security check mechanism makes Java more robust.
the Java language is secure . Java is typically used in a network environment, and Java provides a security mechanism to prevent malicious code from attacking. In addition to many of the security features of the Java language, Java has a security mechanism (class ClassLoader) for classes that are downloaded over the network, such as assigning different namespaces to prevent the substitution of locally named classes, byte code checks,  and provides security management mechanisms (class SecurityManager) for Java applications to set up Security Sentinel.
the Java language is architecture-neutral . Java programs (files that are suffixed with Java) are compiled into an architecture-neutral bytecode format (a file with a suffix of Class) on the Java platform and can then be run on any system that implements the Java platform.  This approach is suitable for heterogeneous network environment and software distribution.

  The Java language isPortable。 This portability comes from architecture neutrality, and Java also strictly specifies the length of each basic data type. Java system itself is also very strong portability, Java compiler is implemented in Java, Java operating environment is implemented with Ansic.
The Java language isinterpreted type of。 As mentioned earlier, Java programs are compiled into bytecode format on the Java platform and can then be run on any system that implements the Java platform. At runtime, these bytecode are interpreted by the Java interpreter in the Java platform, and the classes required during execution are loaded into the runtime environment during the join phase.
Java isHigh-performance。 Java is really high-performance compared to those high-level scripting languages that are interpreted. In fact, the speed of Java is getting closer to C + + with the development of JIT (just-in-time) compiler technology.
The Java language isMulti-threaded。 In the Java language, a thread is a special object that must be created by the thread class or its child (grandchild) class. There are usually two ways to create a thread: one is to wrap an object that implements the Runnable interface into a thread using a constructor of type thread (Runnable), and another to derive a subclass from the thread class and override the Run method, and the object created with that subclass is a thread. It is important to note that the thread class has implemented the Runnable interface, so any thread has its run method, and the Run method contains the code that the thread wants to run. The activity of a thread is controlled by a set of methods. The Java language supports simultaneous execution of multiple threads, and provides a mechanism for synchronizing machines between multithreading.
The Java language isof Dynamic。 One of the design goals of the Java language is to adapt to dynamically changing environments. The classes required by the Java program can be dynamically loaded into the runtime environment, or they can be loaded into the network to load the required classes. This also facilitates software upgrades. In addition, classes in Java have a run-time representation that enables type checking at run time.
All in all, Java technology is highly versatile, efficient, platform-ported, and secure, and is widely used in personal PCs, data centers, game consoles, science supercomputers, mobile phones, and the Internet, as well as the world's largest developer professional community. In the global cloud computing and mobile Internet industry environment, Java has a significant advantage and broad prospects.
Therefore, the excellent programming language Java is the GIS development uses the more two times the development language, especially applies in the network GIS aspect. Network GIS can be built with Java EE technology. such as the development of Web sites to load display map data, analysis and so on, such as Google Map. At the same time, the development of mobile GIS based on Android, because Android development is based on the Java language, so the advantage of Java is the combination with Android.

The link between Java and GIS