Nghiên cứu vector tiles và framework NodeJS trong xây dựng máy chủ cung cấp bản đồ dạng tile

Việc tối ưu hóa khả năng trực quan hóa và tăng khả năng truy vấn dữ liệu không gian trên WebGIS là yếu tố cần được quan tâm khi phát triển ứng dụng WebGIS. Kĩ thuật mảnh bản đồ (tiled map) đặc biệt là định dạng mảnh ảnh (raster tiles) đã được giới thiệu và cung cấp bởi nhiều hệ thống máy chủ GIS như ArcGIS Server, GeoServer với mục đích tăng tốc độ hiển thị dữ liệu không gian. Tuy nhiên, raster tiles có nhược điểm là dữ liệu được gửi tới máy khách chỉ dưới dạng hình ảnh. Điều này dẫn đến hạn chế trong việc truy vấn dữ liệu. Ngoài ra, việc định dạng các kiểu hiển thị cho các đối tượng trên bản đồ cũng bị hạn chế. Kĩ thuật mới vector tiles đã ra đời nhằm khắc phục các hạn chế của raster tiles. Bài báo này trình bày tổng quan về kỹ thuật tiles map đặc biệt là định dạng vector tiles. Ngoài ra, bài báo cũng trình bày các bước trong việc xây dựng một ứng dụng cung cấp dịch vụ vector tiles dựa trên các nền tảng mã nguồn mở miễn phí là: PostgreSQL, NodeJS và MapNik

TANK INFORMATION SYSTEM (TIS): A CASE STUDY IN MIGRATING WEB MAPPING APPLICATION FROM FLEX TO DOJO FOR ARCGIS SERVER AND THEN TO OPEN SOURCE

Tank Information System is a web application which provides comprehensive information about minor irrigation tanks of Telangana State. As part of the program, a web mapping application using Flex and ArcGIS server was developed to make the data available to the public. In course of time as Flex be-came outdated, a migration of the client interface to the latest JavaScript based technologies was carried out. Initially, the Flex based application was migrated to ArcGIS JavaScript API using Dojo Toolkit. Both the client applications used published services from ArcGIS server. To check the migration pattern from proprietary to open source, the JavaScript based ArcGIS application was later migrated to OpenLayers and Dojo Toolkit which used published service from GeoServer. The migration pattern noticed in the study especially emphasizes upon the use of Dojo Toolkit and PostgreSQL database for ArcGIS server so that migration to open source could be performed effortlessly. The current ap-plication provides a case in study which could assist organizations in migrating their proprietary based ArcGIS web applications to open source. Furthermore, the study reveals cost benefits of adopting open source against commercial software's.

Research on Information Retrieval System of Typhoon Based on ArcGIS Server

At the information age, the traditional GIS has already can't satisfy people's demand for real-time access to geographic information, such as typhoon weather phenomenon change at any time. Based on ArcGIS Server platform and Java technology, the typhoon information query system of B/S architecture has been designed. The system can complete the space mapping service release and attribute information query, spatial orientation, motion path of dynamic display, for the typhoon weather forecasters and the public provide real-time access information query platform. At the same time, aiming at common bottlenecks in Web GIS application, the paper puts forward the optimization of the data and the establishment of cache. Experiments show that these two methods in reading speed and response speed figure have improved significantly.

Developing of Agricultural Product Traceability Information System Based on WebGIS

By using WebGIS technology and designing the traceability database of the production, wholesale and sale information of agricultural product, the agricultural product traceability information system based on ArcGIS server is developed and some functions are implemented. Firstly the production place, wholesale place and sale place of the agricultural product is visualized . Then the information of agricultural product is queried and analyzed quickly. At the same time, the shortest path analysis of production place, wholesale place and sale place is implemented. Finally, by using the relationship of production, wholesale and sale of agricultural product, the traceability of agricultural product is researched and implemented.