Designed and developed a web mapping application that displays traffic accidents for analysis
Mn/DOT had implemented a Crash Mapping and Analysis Tool (MnCMAT) which allowed users to select and analyze crash information in a variety of ways. MnCMAT provided improvement over prior manual methods of accessing crash records and significantly reduced manual data requests from local government agencies. However, due to issues with security, data access, maintenance, and functionality, Mn/DOT desired to replace the existing desktop tool with a new application which would be web-based, would conform to the Department’s GIS and web architecture, and would provide access to more current data and enhanced functionality. The new application would utilize the best available technology and would be able to be maintained and enhanced by Mn/DOT staff.
Great Arc designed and developed a Flex mapping application that displays all traffic accidents for the state of Minnesota over a ten-year period. The application can support hundreds of users in local, regional, and state agencies. Users may filter crashes by geographic location as well as by any of dozens of attributes. Maps are rendered using the ESRI Flex API for ArcGIS Server. Great Arc also developed a set of .Net web services that communicate with the source Oracle database to provide data to the Flex client application. Users can view project information, overview maps, and charts depicting selected crash data characteristics using widgets. For viewing data where incidents are densely packed, the application provides ‘stacking’ which graphically shows each crash, symbolized by severity, in a stack which allows users to quickly visualize and access information for crashes in areas with many crash results (see screenshots below).
One of the technical challenges we faced during this project was the requirement to display all traffic incidents for the entire state. Using existing ESRI technologies, drawing these points takes around one minute, so we developed a custom point image web service that can render the same amount of data in a couple of seconds.
Additionally, Great Arc developed a web-based interface, built using Flex, for administering and maintaining the application. This gives Mn/DOT staff the capability to add, edit, and remove users of the system.