Blue Line

Spatial matters in emergency

September 16, 2014  By Jin Y Xie

by Jin Y Xie

Hamilton Police Service (HPS) is the local Public Safety Answering Point (PSAP), transferring area emergency calls to the fire department, emergency medical service or OPP in addition to the HPS.

{Spatial matters}

Spatial information plays a critical role in an emergency call because every incident is associated with a real-world location. Immediate and accurate location awareness can mean the difference between life and loss. The more readily available and clearly visible the information is, the faster the response.

Geographic Information System (GIS) has been integrated with CAD – HPS has used Intergraph’s Computer Aided Dispatch (CAD) system to handle emergency calls since March 1994 – to enhance functionalities through advanced spatial analytics and data visualization. Today, GIS has already become part of a CAD solution, providing quick call location verification and incident analysis, such as values at risk, location of interest (criminal records history for certain period), etc.

As GIS technology keeps evolving, more new powerful analytical and mapping tools are being used in emergency incidents, providing dispatchers and first responders with more valuable information.

{Currency is critical}

Capabilities in CAD can vary greatly due to the quality of GIS data. Especially in recent decades, many communities are growing in both area and population, requiring constant updating and maintenance on GIS data to make sure maps are accurate and current. Imaging how frustrating it would be if emergency calls came from new subdivisions but could not always be verified in CAD.

Prior to 2012, the resources were not available to update CAD mapping data more frequently than every two years. Obviously this could not meet the requirements of emergency services.

In order to take the full advantage of advanced capabilities in CAD, it’s crucial to update GIS data frequently to keep mapping data up to date.

I was hired as a HPS CAD/GIS Analyst in 2013 and successfully updated the CAD mapping data two times in the same year. The accuracy and currency of the location information provided to dispatchers and first responders improved significantly. Our next goal is to update mapping data even more frequently.

{Major accomplishments}

The City of Hamilton’s team maintains quality GIS data and shares it with the HPS. Even though the data format is not compatible to CAD mapping, thanks to the tools of Intergraph’s Geomedia Professional and its extension I/Map Editor, we are able to process and upgrade it to the format that CAD accepts. Here are the major accomplishments in the mapping data upgrade for CAD:

  1. The data accuracy and currency for CAD mapping has been greatly improved. Dispatchers and first responders can now access the most current GIS data.

  2. Successfully implemented routing capabilities: One-way streets make routing quite challenging so few agencies implement this functionality. This functionality is critical in Hamilton, where there are many unique one-way streets in the downtown area. Accurate routing capability is a safety concern for police officers.

By implementing the routing capabilities in CAD mapping data updates, officers are now able to use the functionality without the need for additional devices.

Figure 1: Routing map in Hamilton’s one-way streets

  1. Functionalities improvement: In CAD, dispatchers can hit a button to get an aerial photograph of an area. When the aerial photography is turned on, solid blue areas show the presence of water. The solid blue blocks useful information such as details of small islands. This defect might cause a problem if there is an emergency incident on an island.

The dispatchers did not want the blue area to simply be removed. By analyzing the user’s requirement, I found a solution to fix the defect. First, I added an additional layer for the water body with a symbology of “blue-outline” on the map. Then I modified the codes behind the tool button, so that the two water body layers can be switched with a click of a button. When the aerial photograph is off, the solid-filled blue area is on; otherwise the blue outline is on.

Figure 2. Water body with solid-filled blue area when aerial photograph is off.

Figure 3. Water body with blue outline when aerial photograph is on.

  1. More information available: I have added more layers on the CAD map in the GIS data update, further enhancing the amount of information availability to dispatchers.

  2. Childcare facilities were added to the CAD map.

  3. One-way street arrows now show on the street network, a great visual aid to dispatchers and first responders.

  4. Legibility and cartographic improvement. The legibility of labels for streets and buildings is improved by applying the approach of scale dependency. When zooming in and out the map, font size and density for the labels adjust for better visual effects.

The map symbology is improved as well in the CAD mapping upgrade so there isn’t any symbology confusion for layers such as power lines, railway tracks, etc.


Contact Jin Y Xie at for more information.

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