This study presents an incorporation and application of a two-dimensional, unstructured-grid hydrodynamic model with a suspended sediment transport module in Daishan, China. The model is verified with field measurement data from 2017: water level, flow velocities and suspended sediment concentration (SSC). In the application on the Daishan, the performance of the hydrodynamic model has been satisfactorily validated against observed variations of available measurement stations. Coupled with the hydrodynamic model, a sediment transport model has been developed and tested. The simulations agreed quantitatively with the observations. The validated model was applied to the construction of breakwaters and docks under a different plan. The model can calculate the flow field and siltation situation under different breakwater settings. After we have analyzed the impact of existing breakwater layout schemes and sediment transport, a reasonable plan will be selected. The results show that the sea area near the north of Yanwo Shan and Dongken Shan has a large flow velocity exceeding 2.0 m/s and the flow velocity within the isobath of 5 m is small, within 0.6 m/s. According to the sediment calculation, the dock project is feasible. However, the designed width of the fairway should be increased to ensure the navigation safety of the ship according to variation characteristics of cross flow velocity in channel.

The timely and accurate mapping of dynamic disasters and emergencies is an important task that is necessary for supporting the decision-making that can improve the efficiency of rescue and response efforts. The existing emergency symbol libraries are primarily composed of point symbols and simple line symbols, focusing on the representation of disasters, related facilities, and operations. However, various existing response factors (e.g., the distribution and types of emergency forces) are also important for further decision-making and emergency responses; there is a need to design complex and diverse symbols to represent this rich information. Moreover, traditional mapping systems only provide static map symbols that cannot be easily edited after creation, making it difficult to support interactive editing after the symbols are mapped, thus hindering the representation of dynamic disasters and response factors. This article targets a solution of the above issues by proposing a procedural construction method of interactive map symbols for dynamic disasters and emergency responses. There are two primary research points. First, an emergency response and decision symbol library was classified and integrated into the existing attachments to form a richer symbol library for comprehensively representing disasters and emergencies. Second, an interactive map symbol procedural construction method was designed based on (1) primitive geometric compositions and geometric graphics algorithms to construct the map symbol graphics; (2) an interactive graphics control and drawing attributes configuration method to support user interactive editing of the visual variables of the mapped symbols; (3) and a dynamic updating and drawing strategy to support the real-time refreshing of the changing visual variables. The experiment was conducted using the Wenchuan earthquake as a case study, and the results demonstrate a powerful capacity of the produced interactive map symbols, which will contribute to the improvement of the mapping efficiency and representation capability of disasters and emergency response.

The rendering of line joins is important for representing linearly changing information and for allowing map readers to develop a more comprehensive understanding of the real world from maps. Although a range of software-based and graphic processing unit (GPU)-accelerated rendering methods have been developed to render wide lines, linear map symbols are much more complicated compared to commonly used line types in drawing geometric lines, and the rendering of lines joins should consider a filling process that is continuous, rational and efficient. This paper proposes an improved method to generate and adjust the U–V parameters (which are used to control the rendering process of linear map elements within the GPU shader language) of the vertices in line joins to provide a customizable approach for map designers to implement different drawing effects of line joins for drawing different line elements. Based on the customizability, the continual and rational rendering of line joins are studied. Two experiments are conducted to demonstrate the method’s feasibility and efficiency; the results demonstrate that line joins can be effectively and rationally drawn with a variety of linear map symbols. The efficiency of rendering linear map elements is also improved with this method.