Space geography Technology and database management system

Data | The geography of the database is becoming an increasingly important part of our daily life. Space geography technology is playing a more and more important role in the fields of cutting-edge technology such as aerospace, agriculture, energy, transportation, finance, telecommunications, retailing, and other traditional commercial areas. With the development of the potential of computer based spatial geographic information, a great deal of human and material resources are devoted to the research of space geography technology, which also prompts people to create a database management system based on geographic data storage. But it was not until 1981 that the first commercially available geographic information product, Arc/info, began to be truly effective in integrating space geography technology and databases into a single system.
The booming of space geography technology
----In fact, the application of space geography technology can be expanded with our imagination. Among them, the focus of the B to B Market will become a high growth area. An enterprise can apply this technology in its supply chain management to track the location of a particular customer's order, or to provide targeted management. Many media industries can provide targeted advertising to customers who meet specific demographic statistics if they understand the location of all their customers. Although the Internet technology is not related to geography, but people live on the ground, so it will inevitably use space geography technology. In addition, in the United States, the government requires all cellular phones to be implemented by the October 2001 GPS (Global Positioning System) function, space and geography technology in this field will also be useful. It can lock the caller's position within 400 meters, and the call center receiving the emergency call can also convert the latitude and longitude information into digital map.
Another important area of application of----space geography technology is client application. It enables visualization functions, such as maps or graphs, and enables query and analysis functions. For example, when a user runs a query operation, the client application writes it using SQL and passes it to the database to execute the query process. The database sends the query results back to the client, which understands how to represent or display data. The client can draw highways with red lines, draw auxiliary routes with Gray line, and display other location types, such as fire hydrants, as icons. The client can also perform analysis functions, such as calculating the distance between two points. In the web-based GIS (GIS) implementation process, many client functions can be handled by the middleware located on the application server.
Database management system to meet the difficulties and enter
----Space geography technology is providing assistance to industry and government in a way that is not previously conceivable, and more and more applications need GIS support. However, existing available data is present in a variety of different format files, which greatly limits the open access to geographic data. Although file-based geographic data can be easily shared within a small project group, enterprise-wide data allocation is difficult to handle. This situation often leads to the duplication of multiple copies of the same geographical data between different working groups in the same enterprise. Without a highly organized process to manage the duplication of these data, the consistency and completeness of the data are difficult to guarantee, thus affecting the rational formulation of decisions based on the above data. In addition, open geographic data and storage in the relational database management system of other enterprise core data integration process also encountered difficulties, open geographical data access is limited. This is because the design of the relational database management system module can only support fairly limited data types such as values, characters, and dates. In addition, CAD and graphics processing systems have developed their own data formats, forcing anyone who wants to integrate GIS, CAD, and raster graphics data to use multiple data converters.
----At present, with the continuous development of technical personnel, relational databases have become more and more space capable, such as the ability to organize and store geographical features, provide R-tree index and data blade technology, so as to ensure that many mission-critical applications run faster, more secure and easier to implement.
----organization and storage geographic characteristics
----in a relational database management system module, the data is stored in a table that is composed of rows and columns. A cell that is composed of rows and columns is called a field, and the data contained in the field is called a value. A row represents a specific event, distance, or geographic attribute, and the column contains the attributes for that attribute. Properties have many types, such as dates, text strings, or numbers. And now some relational databases like Esri Spatial datablade Engine (SDE) for Informix start experimenting with extended SQL data types (as shown in Figure 1), making the geographic feature a numeric type stored in the column.

The----enables applications to store and manage complex geographic data by adding spatial data types in object-related database management systems. Doing so does not change the existing database or affect the current application, but simply adds a "shape" column to the existing table, providing the software to manage and access the geographic attributes referenced in the column. Using space tables, users can perform data queries and table accumulation as before, and can write queries to return space attributes or use space attributes in requests. The creation and maintenance of spatial objects and spatial index tables are automated and transparent to users.
----R-Tree Index
The key to----fast access and efficient processing of data is indexing. Although there is an extensible data type, efficient spatial indexing is more important to the very complex nature of geospatial data.
----Traditional spatial data indexing methods mainly have the following two kinds. The first approach is to create a spatial index outside the server and store it in BLOBs (Binary Large object, large binary objects). The user can then access the index and retrieve the BLOB through the middleware when needed. However, regardless of how well the index structure is performing, the retrieval and maintenance of blobs can result in intrinsic I/o overhead and concurrency problems, resulting in reduced speed and efficiency, because you want to include the retrieval part from the external server. The second approach is spatial partitioning, where space is split into units according to a defined grid or other layered structure (such as Shivisha). Each cell is assigned a number, and each space object is associated with the number of its overlapping units. But the spatial and nonlinear sequences, many of the spatial characteristics of the irregular requirements of complex retrieval and a number of possible errors of the necessary checks. This shows that this is also a slow and inefficient approach.
----By contrast, R-trees (Region trees, regional tree graphs) are high-performance, multidimensional access methods that are built into the database kernel and collaborate directly with epitaxial data types to properly manage geospatial data. Unlike a standard index, a R-tree does not divide the entire space into a complete overlay consisting of non-overlapping contiguous cells. Instead, it uses a method of data segmentation, the "band box" that allows each object to automatically be determined by the space shape, which can overlap each other and does not need to cover the entire space (as shown in Figure 2), does not take time for developers to anticipate the spatial scope of the data.
----Data Blade (Datablade)
----The internet is a kind of data dissemination. So how do we extend our company to the internet without adding too much cost? How do I turn business data into Web content? How can we use existing data to make the company more competitive? In response to the above issues, as early as 1996, Informix introduced data blade (Datablade) technology, which integrates any data from any source, providing a stable and flexible Internet application environment.
----For example, a customer needs to query its current SQL database to search for all dwellings within 200 meters of a company's distribution point, and if only standard SQL is used, this seemingly simple query is actually very complex. With Informix Datablade Technology, customers are able to expand the application's intelligence by increasing the geographic and regional data mentioned above. What will be the result? The number of coded lines is reduced, the speed of execution accelerates, and the customer gets the exact, not the approximate, answer they need.
----as an extension of server performance, Datablade modules are integrated into the core of the engine, integrating traditional data types with rich Web content, without sacrificing the reliability and scalability of traditional relational database management systems. Using a single Datablade module or integrating several modules together, you can create unique information management solutions that meet the unique needs of your customers. Datablade modules are written in a common programming language, they can do the general program language work, do not need the server or other data source calls. and the reusable module developed by Datablade technology can be embedded directly into the database core, as a part of the database server, this can greatly expand the data support ability of the core database server and improve the overall performance of the database server.
----Regardless of how the customer's business develops and changes, regardless of what information the customer is managing, and which industry the customer is in, the use of Datablade technology can always quickly and cheaply create complex, intelligent solutions that enable customers to put their products to market in a shorter time, Greatly improve the competitiveness of customers.
Application development is endless
----In the past 25 years, people have used GIS, CAD and graphics processing system to create a large number of digital spatial data. Now, the following three major trends are driving the growing demand for new open spatial data management. First, the need to expand geographic data access within the enterprise is increasing rapidly; Secondly, enterprises begin to adopt spatial positioning to integrate their core business data, and increase spatial analysis in their business operation. Third, the widespread popularity of Internet access poses a great pressure on government agencies at all levels to continuously provide public Internet access to existing geographical data.
----Enterprises will be the biggest beneficiaries of space geography technology application, because they can make full use of the advanced visualization and Analysis technology of space geography technology in commercial operation. By adding a space dimension to the business system, analysts say, companies can make better decisions. For example, when a cellular service provider expands coverage, it needs to figure out where the potential users are. The application of Space geography technology will help to answer this question and bring better and more intelligent business decision.