1.1.3 GIS application framework

1.1.3 GIS application framework

GISSince the development of the software, it has no longer been a simple application of spatial data storage and display. Many advanced functions such as 3D analysis, spatial analysis, Geographic Statistics, and geographic services have been applied in practice, businessGISThe software has evolved from desktop componentsWeb ServiceOfGISService. "GISConverting from database method to knowledge Method4". BecauseGISThe fields involved have become very broad. Commercial companies or individuals want to write a highly scalable and functional library in a short time.GISThe platform has become a very difficult task. Of course, the manpower, material resources, and financial resources required for such operations are also very high.

in actual application project development, GIS Program members tend to use a specific GIS perform secondary development on the platform, for example, the ArcGIS Engine component library we selected. This book introduces GIS application framework nbgis is also built on the general GIS platform, this is also the development component of many GIS projects. Of course, select ArcGIS Engine as the framework GIS some class libraries are not the only class libraries in the world. Product-level and open-source GIS the secondary development component library already has many practical products, but ArcGIS Engine is one of the most familiar and widely used tools and the most powerful functions among developers.

Applications developed based on the framework mode can be divided into two layers: the framework layer and the application layer. The framework layer is not a plug-in. It is developed by some more basic class libraries or frameworks. Among these basic components, the underlying layer is the operating system layer. In addition to providing access to hardware devices, it also provides the necessaryAPIAccess to all layers on the operating system layer is provided as a programming model, such. NET Framework,MFCAndJREThe basic framework layer provides the most general functions and components based on the operating system. The basic framework layer is the custom framework layer compiled by developers, developers need to analyze the requirements of the application layer, extract general logic, and implement it in the Custom framework layer.

GIS(Geographic Information SystemGeographic Information System (GIS) application framework is the topic of this book. We will develop plug-insGISThe application framework is not associated with a specific business process, but is purelyGISData display and Function Support Framework, a software platform for browsing and editing geographical data, or. Net2.0 frameworkAndArcGIS engine9.2A simple simulation of Component Library ConstructionArcMapThe former provides general data processing and logic components, and the latter provides map controls and map data operations necessary to display geographic data.

Unlike other application frameworks,GISApplication Frameworks of different types are destined to be visualization applications. In geographic information data management, data visualization and storage are equally important.GISThe most basic function of the framework is to display geographical data and perform a series of data analysis, processing, and output tasks.GISThe visualization function of the Framework is generally implemented through some commercial controls, and few people develop the framework on their own from the underlying layer. For exampleArcGIS EngineMap ControlMapcontrol,PagelayoutcontrolAndToccontrol.

In businessGISApplication project development in progress,GISFramework (GISPlatform) is also very common.GISDifferent from other professional software, application software is often closely linked to the workflows of end customers. Because the workflows of different departments are different, this makes it necessary for a company to modify its own molding products based on the actual situation of its customers.

To improve work efficiency and product reliability and reduce project development costsGISSecondary developers will organize the company's core programmers to developGISApplication Frameworks encapsulate some common core functions. These frameworks may use different technologies and strategies, but their goals are the same: reduce the workload of repeated coding and improve programming efficiency, it provides a good platform and workflow for the development work of the project personnel. This is the process to be discussed in this book.

Having a scalable framework means that application project developers do not have to build a system from the beginning after receiving a new project task. They only need to follow a working modeGISThe application framework is inherited and extended, and the previous development results can be used as much as possible to buildUILayer, or functional component platforms that are consistent in the logic layer, and the components of these platforms are naturally reusable. This method is undoubtedly more attractive than the original encoding method.

4 What is arcgis9.2? ESRIPresidentJack dangermond