Research and establishment of transportation infrastructure information system based on arcIMS

Http://www.gisforum.net/show.aspx? Id = 1130 & cid = 19

(Guangxi basic geographic information center Guangxi Nanning 530023 Email: 13507714592@vip.sina.com)

【Abstract】this paper mainly introduces the design and implementation of ESRI-based Web GIS platform ArcIMS and Guangxi transportation infrastructure information system.
【Key words】 Web GIS; ArcIMS; transportation infrastructure

1 Preface
Since the reform and opening up, the transportation infrastructure construction in Guangxi has achieved rapid development. The highway network structure has been continuously improved from scratch to many; the port throughput is significantly enhanced, and the inland river transportation facilities are greatly improved. The amount of traffic infrastructure information is growing rapidly, and traditional management methods are no longer suitable for the growing traffic needs. It is necessary to make full use of the latest developments in computer application technology, using IT technology, GIS (Geographic Information System) technology, multimedia technology, combined with industry planning and management needs, develop a Web GIS-based transportation infrastructure information system.
The transport infrastructure information system of Guangxi adopts the ESRI Web GIS platform ArcIMS to meet the requirements of increasing traffic infrastructure information, the basic information of highways, ports, and inland river shipping hubs that have been built, under construction, and are currently working in the early stage, provide accurate and informative information to traffic department leaders and management personnel in a timely manner.
2 Introduction to Web GIS technology and ArcIMS
2.1 Web GIS (Internet Geographic Information System) Technology
In recent years, the rapidly developing Internet has become a new GIS system platform. The use of Internet technology to publish spatial data on the Web for users to query and use is an inevitable trend of GIS development, as one of the main development directions of GIS, Web GIS technology is an indisputable fact. Currently, Web GIS implementation methods include Java programming, ActiveX, public Gateway Interface (CGI), server application interface (Servlet API), and Plug-in method (Plug Ins). Most GIS manufacturers at home and abroad have launched their own Web GIS products. In foreign countries, such as AutoDesk's MapGuide, ESRI's ArcIMS, and MapInfo's MapXtreme; in China, such as Wuhan's GeoSurf, Beijing's SuperMap IS, and Wuhan's AFInternet GIS.
Web GIS technology has at least the following advantages:
(1) high scalability: In terms of Web GIS, it can be released on the Internet to meet the requirements of GIS websites and can also be used on the Intranet to meet the requirements of the internal LAN of the Organization. It can also better integrate with existing systems within the Department.
(2) thin client: All map, attribute data, programming and other work are carried out on the server side. The client only needs a browser such as IE to work (some Web GIS products need to install plug-ins ). The client can access the Web GIS service on the server and send various requests to the server. After receiving the requests from the client, the server analyzes and processes the data on the server, return the result image (or vector data) and retrieved attribute data to the client.
(3) low network bandwidth requirements: Because any client operation sends a small instruction set to the server, after the server processes client requests, the client transmits JPEG images (or vector data) and attribute data with a high compression ratio, which has low network bandwidth requirements.
(4) High Security: from the perspective of public services, because external service projects can be controlled by servers, users can only access materials that match their own permissions, this avoids unauthorized access to confidential data. From the perspective of MAP and industry data confidentiality, the server sends a result image (or vector data) and attribute data to the client, the client can never obtain the GIS vector data and attribute data on the server, which fundamentally protects the data that has been collected and processed by a large amount of energy and protects the investment of data providers.
2.2 Introduction to ESRI's Web GIS platform ArcIMS
(1) architecture of ArcIMS (see Figure 1 ):
As the second generation Web GIS product of ESRI, ArcIMS is mainly used in Internet/Intranet
Environment provides GIS services. It contains three utilities used to build map applications with B/S structures.
① Map service management tool Administrator: provides two map services, raster and vector, which are used to read AXL files generated by Author.
② Map data organization tool Author: provides data organization for raster data and vector data (Shape format) to generate an AXL file.
③ Web publishing site design Designer: You can quickly customize the interface seen by the client to generate a site.

Figure 1 architecture of ArcIMS

(2) features of ArcIMS:
① Supports multiple operating system platforms, such as NT4, Windows2000, and UNIX.
② Multiple Web servers are supported: IIS, iPlanet, Apache, etc.
③ Client Scalability: The thin client (the map uploaded to the client is raster data) includes HTML Viewer, and the fat client (the map uploaded to the client is vector data) includes JAVA Viewer, ArcGIS Desktop, and arcw.e (free of charge) wireless devices (such as cell phones and PDAs.
3. System Function Design:
In Guangxi Transportation Infrastructure Management Information System, Servlet ctor and HTML Viewer of ArcIMS3.1 are used, and ASP and JavaScript languages are used. Dreamweaver MX of MacroMedia and website development tools of Microsoft Visual InterDev6.0 are used for secondary development, the function of retrieval, query, and comprehensive analysis of traffic infrastructure information is realized. The overall functional structure of the system is as follows:

Figure 2 Structure of the Guangxi transportation infrastructure information system

3.1 basic map operations
The electronic map of the system provides browsing functions such as roaming, scaling, full graph display, and display by scale. It also allows you to easily view the full graph and observe local details. It can also control whether any layer is displayed.
3.2 data management and maintenance functions
The system provides convenient and effective data entry, management, and update and maintenance functions. The system manages two types of data: electronic map data and Guangxi transportation infrastructure information (including highway, port, inland river shipping hub and Waterway Information ). You can update these two types of data at any time as needed to ensure the timeliness of the data.
3.3 powerful visual information query and display functions
· Supports graphic attribute query, graphic attribute query, and fuzzy query. You can quickly query the geographic locations of various highways, ports, inland river shipping hubs and channels in Guangxi, and highlight the electronic maps of the selected targets and related surrounding environments, displays the details of the query target in the form of texts, images, videos, and other multimedia.
· Allows you to query coordinates at any position on an electronic map.
3.4 Data calculation and Spatial Analysis
· The linear distance between two or more targets can be calculated.
· Buffer analysis (or radiation range analysis), such as point buffer analysis, line buffer analysis, and surface buffer analysis.
3.5 Print Output
You can print out electronic maps and various information materials.
3.6 permission management
The system uses user logon permission management. Users of different levels have different permissions to ensure the security of the system and data.

Figure 3 interface of Guangxi transportation infrastructure information system

4 experiences in Secondary Development of ArcIMS
4.1 how to select Viewers
Viewers determines the functions and appearance of the ArcIMS site and the space, attribute query tools, and display tools provided. Therefore, when using ArcIMS for development, you must first consider "What kind of client is selected ?", ArcIMS provides three types of viewer for selection. Generally, the following factors should be taken into account: Is the site built on the Intranet or the Internet? What browser does the user use? What is your GIS background? Required functions? What is the workload of customization?
To create an Intranet site, Java Viewer (fat client) may be a wise choice. In the Intranet, it is relatively easy for users to download and install plug-ins on the client. Java Viewer supports vector data streams and richer client functions, such as MapNotes and EditNotes, which are not supported by HTML Viewer. Once the client loads Applets, the map display and query speed will be very fast. ArcIMS supports two types of Java Viewers: Customizable Java Viewer and standard Java Viewer.
If you want to create an Internet site and the client does not need to download plug-ins, you can consider HTML Viewer (thin client ). The main reason for using HTML Viewer is that there is no need to customize it to obtain powerful functions. In addition, HTML Viewer supports clients and servers on all platforms. Developers only need to be familiar with HTML and JavaScript to build websites through HTML Viewer. The main disadvantage of HTML Viewer is that the client can only return raster data, so the response time is slow when accessing large data volumes.
4.2 How to easily and quickly customize the HTML viewer by modifying the arcimsparam. JS File
First, use ArcIMS Author to define the map application content, including adding data, setting map attributes, and generating an online map as a map service. Then, based on the data defined by ArcIMS Author, ArcIMS Designer is used to generate Web services that users can browse. ArcIMS Designer allows you to select the map services, templates, and functions used by the customer's browser through a series of dialog boxes.
In this case, HTML Viewer generates a series of files. An important parameter file is the ArcIMSparam. js file located in the site directory. This file contains a set of JavaScript variables that affect the site appearance and work style. Most HTML Viewer customization can be done by changing the values of these variables. ArcIMSparam. the main variables contained in js can be used to change the map service and MAP range used, set the initialization display of the legend, and define the norm of the acetate layer, copyrighted text, display of definition attribute fields, tool change, and toolbar. For example:
① Add a Chinese character alias to a field:
Var useFieldAlias = true;
FieldAliasList [0] = "CODE: CODE | RNAME: Name ";
② By default, only attributes of the current layer can be queried. to query attributes of all layers, modify:
Var useIdentify = false;
Var useIdentifyAll = true;
4.3 Use ArcXML (Internet-based spatial data description language) to expand and customize system functions
ArcXML is a specific XML language designed for data exchange between different components in ArcIMS.
ArcXML uses a hierarchical tag system to provide a basic framework for communication between ArcIMS components. There are five tags in the ArcXML system to build the basic framework. The ArcXML tag is included in the Declaration section of ArcXML. The four root sub-tags CONFIG, REQUEST, RESPONSE, and MARKUP define the type of ArcXML declaration. CONFIG labels configure maps by setting properties and defining layers. REQUEST, RESPONSE, and MARKUP labels are used for communication between different parts. The REQUEST tag is used for all requests sent from the client to the space server. The RESPONSE tag is used in the RESPONSE returned by the Space server. The MARKUP tag describes the modifications made on the client through the EditNotes tool.
ArcXML is a basic method for implementing more flexible and complex system functions and map display.
4.4 use JavaScript to expand and customize system functions
JavaScript is a scripting language that supports the development of Web application client and server component. On the client side, it can be used to compile programs executed by Web browsers in the context of Web pages. on the server side, it can be used to compile the Web server program that processes the information submitted by the Web browser and accordingly updates the Web server program displayed by the browser. The HTML Viewer of ArcIMS contains a JavaScript function library by default. Hundreds of functions and hundreds of global variables are designed as the core of custom development. These functions are grouped by function and saved as *. js. We can rewrite or supplement these functions, which is also necessary for in-depth custom development. Whether there is a well-organized Javascript function library determines the development efficiency and quality.
5 conclusion
The establishment of the Guangxi transportation infrastructure information system provides a visual decision-making assistant management tool for the Guangxi Transportation Management Department, which significantly improves the planning and management level of management personnel, this has promoted the development of industry management in a scientific, standardized, and information-based manner. In the future, combined with the application of e-government in traffic management, Web GIS technology will have broad application prospects in traffic infrastructure management.

References:
[1]Http://www.esrichina-bj.cn/. ESRI China (Beijing) Co.
[2]Customizing ArcIMS HTML Viewer, GIS by ESRI, 2001