CPTMS Camera Controller

Specification

See the User Interface Prototype in the Subversion repository:  trunk/webapps/cptms/CameraDisplay.html
Purpose: Display four camera views of current CPTMS highway conditions in a grid layout.

Functions;

1. The user selects which of the four displays is to be updated.
2. The user selects which route (highway) is to be displayed. The list of routes is 1 5 22 55 57 73 74 91 133 142 241 261 405 605.
   Once a route is selected, the camera drop down box filters the camera choices to just those on the selected route.
3. The users selects a camera. The chosen camera view appears in the selected display.

Data Sources

1. cptms/data_layers/cctv_locations_D12.gson is a static file containing the filename and locationName (among other things) for all the CCTV cameras.
2. webapps/dynamicdata/highway_status.json is updated every 30 seconds with traffic flow. The camera display controller reads this file every 30 seconds and obtains the "color" property for each camera currently being displayed. It then chooses the corresponding image to display from the cptms/images folder. lime = freeflow, yellow = slow, red = stopped.

The complicated part is that the highway status data doesn't include where the CCTV cameras are. Luckily CPTMS already has the algorithm for determining where the nearest CCTV camera is for a given VDS. This could be used as is (do an exhaustive search), or write the converse algorithm that given a CCTV will find the traffic flow at the nearest VDS.