Construction and visualization of three-dimensional (3D) complicated objects has become an important task in many GIS and their applications. Main process to construct a true 3D virtual scene with the programmable visualization environment OpenGL for water conservancy works is introduced. A simulation system developed by the authors is presented for importing, filtering and visualizing of complex geographical related data. Culling, lighting, shading and antialiasing were introduced to enhance the 3D visualization effects of the objects. Aspects like presentations of data with spatial dependence, virtual roaming in the terrain and geographical frame of reference and in time, interaction techniques are presented.

This article embarks from the fluid position sensor constitution principle analysis, gives deep insight into the typical application of fluid position relay in the draining water automatic control. It carries on a quantification analysis of the fluid position relay technical performance, theoretically infers the suitable distance scope of fluid position relay measurement (examination) in each different water quality situation. And PLC (programmable logic controller) and the configuration and network technology, water conservancy project object function remote control and surveillance are introduced.

This paper try to promote a data exchange mode based on dual-port RAM and UDP datagram to achieve high-speed data communications in distributed control system. The purpose is to explore a high-performance, low CPU occupancy, high-speed, reliable exchanging mechanism for any amount of data. The model proposed a Dual-port RAM that one port connects the local CPU and the other port connects specific control logic that have reading and writing the Dual-port RAM and net communications functions, the control logic undertakes organizing, sending and receiving and analyzing UDP datagram and achieves the dual-port RAM reading and writing and sends interrupt requirement to the local processor. This model can not only implement efficient data exchange but also provide of interruption mechanism of real-time responding. The paper discusses the needed function modules for achieving these aims and expounds system composing and technical advantages. The paper also analyzes the system developing feasibility, and demonstrates that this model is an advanced, high-performance and promising communication program of distributed control system.