Proposed Architecture and Implementation
To solve the limitations of the current architecture and implementation, we propose to move the geospatial rendering to the client-side with a more intuitive user interface that will be more responsive to user interaction and we will create an open and flexible server-side architecture that will allow for the addition of multiple data sources.
Architecture
In contrast to the current system, the service oriented architecture (SOA) allows for many services such as Google Maps, Web Feature Services (WFS), and ArcIMS to provide clients with data that is then rendered on the client-side using a Javascript-based tool called OpenLayers(see Figure 2).
OpenLayers is an open source Javascript library for delivering dynamic map content to any web page. It can display map tiles and markers loaded from any source and is supported by the open source community. By abstracting out the server side and setting up a common interface between the client and the server side, any map service or custom coded library can provided content and functionality to the client removing the limitation of waiting for the commercial vender to provide new features and bug fixes. User interaction will also be improved since the clients have more control over rendering and visualization; however, some of the advanced rendering capabilities provided by ArcIMS would have to be custom coded and there will be more computational load on the client. This increased computational load is partially mitigated by the increasing computational power available to common users.
!mm_arch_new.jpg!Figure 2. Proposed Architecture
Another advantage of this SOA is the ability to integrate current and future capabilities being developed by NCSA Cyberenvironments and Technologies (CET) division such as high performance computing access, scaling for large data, data analysis, provenance tracking, and metadata integration to deliver a richer user experience and to potentially collaborate on future projects to provide required functionality by the Market Maker Community.
Implementation and Technology
The development of the web mapping component will utilize an agile approach to software development and incorporate user feedback to deliver a high quality product. In the sections that follow, some high-level detail will be provided about the technologies that will be used and how they will be implemented in the component.