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GIS Application - Fire Service Vehicle Mounted Data System (VMDS)
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This video presentation is of the GIS solution, a small part of the overall Vehicle Mounted Data System (VMDS), deployed on Scottish Fire and Rescue Service fire trucks/appliances. The video highlights the technical side of the solution and the free and open source components used in its makeup.
The system is comprised of web based software (ASP, HTML, dHTML, VBScript, JavaScript and AJAX) running locally in full screen kiosk mode using Internet Explorer 6 (NK).
It is deployed on vehicle mobile data terminals (Windows XP SP3, 4 Gb RAM, with IIS 5.1 and FastCGI) and is also available across the service intranet from a central server (Windows Server 2003 R2 Standard edition SP2, 4Gb RAM, with IIS 6.0 and FastCGI).
The application is not public facing due to security restrictions and is therefore not accessible via the public internet.
The GIS page takes advantage of the super-fast Google Chrome Frame (GCF) JavaScript engine and uses SVG for graphics rendering. Internet Explorer 8 (R) is deployed across the intranet and uses VML for graphics rendering.
Maps are rendered using MapServer 6.2.1 (MS4W 3.1.0-beta1) - WMS/WFS with PostgreSQL/PostGIS as the back end database. OpenLayers 2.13.1 JavaScript library is used on the client for map manipulation using touchscreen only: There is no local keyboard or mouse input.
OpenLayers WFS calls are made via a custom ASP proxy host using ServerXMLHTTP.
On vehicle clients update automatically every hour using Rsync over wireless by comparing HDD contents with the central server and transferring only byte level differences.
The base map is a tiled OpenLayers WMS layer that uses a host array of servers in order to circumvent the maximum number of simultaneous persistent connections per server. Locally, the Windows hosts file has multiple entries pointing at 127.0.0.1. Care should be taken in using this approach as there is a 40 connection limit in IIS 5.1 which is easily reached. Other IIS versions, and Apache, do not have this limitation.
A MapServer grouped WMS layer supplies the image tiles and is made up of 4 raster layers and 9 layers created dynamically from PostgreSQL/PostGIS data. Viewable layer data is controlled in the MapServer MAP file using MINSCALEDENOM and MAXSCALEDENOM. There is no tile cache with all tiles being created dynamically when requested.
A custom OpenLayers Pan Zoom Bar is available in the intranet version with the zoom bar at the bottom of the screen providing touchscreen zooming to pre-defined map scales and map types.
The system can be deployed using Open Street Map but the version shown in this video uses maps supplied by Ordnance Survey. The raster maps are free to download and use under the Ordnance Survey OpenData Licence. MasterMap data and 1:50K Raster are licenced under the One Scotland Mapping Agreement.
The hard drive footprint for all the map data is only 27 Gb.
OpenLayers Vector layers with clustering strategies are deployed with some data being retrieved from a MapServer WFS that connects to a Microsoft Access database (WKT) via ODBC with a MapServer CONNECTIONTYPE of OGR. Other data sources include ESRI Shapefiles both for Mapserver WMS and WFS.
The VMDS is connected to a TETRA radio that receives mobilising messages via packet data from the CAD system at a central control room. When a fire truck is mobilised to an incident, the GIS automatically shows both the fire truck location and the incident location at a suitable zoom level.
An AVL feed constantly updates the fire truck position in relation to the incident and the zoom level is automatically adjusted accordingly. The angle of the fire truck graphic is set using OpenLayers style map rotation with the value being derived from the AVL NMEA sentence.
Cautions i.e. school zones, weight, width and height restrictions are also shown automatically to warn crews of possible dangers en route. In addition to this visual warning, a specific audible warning sound file is also played when approaching the particular hazard. The vehicle speed and heading are used to calculate exactly when the warning is played giving appropriate time to take action if required.
The system is comprised of web based software (ASP, HTML, dHTML, VBScript, JavaScript and AJAX) running locally in full screen kiosk mode using Internet Explorer 6 (NK).
It is deployed on vehicle mobile data terminals (Windows XP SP3, 4 Gb RAM, with IIS 5.1 and FastCGI) and is also available across the service intranet from a central server (Windows Server 2003 R2 Standard edition SP2, 4Gb RAM, with IIS 6.0 and FastCGI).
The application is not public facing due to security restrictions and is therefore not accessible via the public internet.
The GIS page takes advantage of the super-fast Google Chrome Frame (GCF) JavaScript engine and uses SVG for graphics rendering. Internet Explorer 8 (R) is deployed across the intranet and uses VML for graphics rendering.
Maps are rendered using MapServer 6.2.1 (MS4W 3.1.0-beta1) - WMS/WFS with PostgreSQL/PostGIS as the back end database. OpenLayers 2.13.1 JavaScript library is used on the client for map manipulation using touchscreen only: There is no local keyboard or mouse input.
OpenLayers WFS calls are made via a custom ASP proxy host using ServerXMLHTTP.
On vehicle clients update automatically every hour using Rsync over wireless by comparing HDD contents with the central server and transferring only byte level differences.
The base map is a tiled OpenLayers WMS layer that uses a host array of servers in order to circumvent the maximum number of simultaneous persistent connections per server. Locally, the Windows hosts file has multiple entries pointing at 127.0.0.1. Care should be taken in using this approach as there is a 40 connection limit in IIS 5.1 which is easily reached. Other IIS versions, and Apache, do not have this limitation.
A MapServer grouped WMS layer supplies the image tiles and is made up of 4 raster layers and 9 layers created dynamically from PostgreSQL/PostGIS data. Viewable layer data is controlled in the MapServer MAP file using MINSCALEDENOM and MAXSCALEDENOM. There is no tile cache with all tiles being created dynamically when requested.
A custom OpenLayers Pan Zoom Bar is available in the intranet version with the zoom bar at the bottom of the screen providing touchscreen zooming to pre-defined map scales and map types.
The system can be deployed using Open Street Map but the version shown in this video uses maps supplied by Ordnance Survey. The raster maps are free to download and use under the Ordnance Survey OpenData Licence. MasterMap data and 1:50K Raster are licenced under the One Scotland Mapping Agreement.
The hard drive footprint for all the map data is only 27 Gb.
OpenLayers Vector layers with clustering strategies are deployed with some data being retrieved from a MapServer WFS that connects to a Microsoft Access database (WKT) via ODBC with a MapServer CONNECTIONTYPE of OGR. Other data sources include ESRI Shapefiles both for Mapserver WMS and WFS.
The VMDS is connected to a TETRA radio that receives mobilising messages via packet data from the CAD system at a central control room. When a fire truck is mobilised to an incident, the GIS automatically shows both the fire truck location and the incident location at a suitable zoom level.
An AVL feed constantly updates the fire truck position in relation to the incident and the zoom level is automatically adjusted accordingly. The angle of the fire truck graphic is set using OpenLayers style map rotation with the value being derived from the AVL NMEA sentence.
Cautions i.e. school zones, weight, width and height restrictions are also shown automatically to warn crews of possible dangers en route. In addition to this visual warning, a specific audible warning sound file is also played when approaching the particular hazard. The vehicle speed and heading are used to calculate exactly when the warning is played giving appropriate time to take action if required.
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