METHODOLOGY

A: Methodology procedures for Community Centres and Hospital Maps

  • Map data points of all Vancouver Community Centers (CC) and hospitals in the GVRD base map. Note that Community Centers in this project are considered to be alternative safe places for people to be during emergency as they are located close to food banks and other services. On the other hand, hospitals are crucial units that needs to be included in the maps for people to turn back to in case of injuries and other health issues.

  • Create buffer zones around CCs and hospitals to determining their coverage areas and distance adjacent from one another so that people can make wise choices to which ooint to go based on their locations. Since regular radial buffers tend to overlap a lot and CCs locations are almost clustered; this would make it hard to analyse because the overlayed buffers would cover some of the CCs visually. Therefore, we decided to use Thiessen Polygons for this analysis process.
    • NOTE: When the theiessen tool was applied it did not cover the whole region of Vancouver such as Stanley Park because the automatic algorithm did not take in consideration water areas and coastlines. Therefore, a manual manipulation by using the editor tool had to be applied to those areas of interest ignored by the thiessen polygon calculation.
  • Along with Hospitals and CCs a road network layer was added and overlaid on top with a faded gray color to give a location perspective with respect to roads as means of transport if just in case some of the roads would be in use during emergence time. However, in this project roads and skytrain routes were not given a high priority in the assumptions that they could be closed and considered hazardous places for people to use during emergency and therefore their feature details are not clearly displayed and documented on our maps.

Below are two complete maps of Hospitals and Community Centers based on this process.

MAP 1: Community Centers Locations in Vancouver

MAP 2: Hospitals Locations in Vancouver within Buffered Zones


B: Methodology procedures for the Multicriteria Evaluation Map (MCE Map)

In order to identify most vulnerable versus safe areas in Vancouver in case of earthquake emergency an MCE analysis had to be conducted. Within the scale and context of this project factors that were considered for the MCE analysis included:

  • Transformer locations ( high risk location)
  • Slope (slope > 35 degrees = high risk)
  • Water body areas ( high risk)
  • Liquefaction ( risk rate based on soil type i.e. landfill, silty, sandy and clay are less stable hence high risky areas)

Consider the map below that displaying the surficial topography of Vancouver soil type and its stability in the MCE analysis.

MAP 3: Surficial Geology Greater Vancouver

The flow chart below summarizes processes taken in making the MCE map.

The evaluation of the MCE was performed by using weighted sums where by:

  • values below .5 were considered relatively safe and coloured green
  • values between .5 and 1 were considered kind of dangerous and coloured yellow
  • values above 1 were considered dangerous as they were near at least 2 sources of danger near by and coloured red.

Maps that display this color code are shown with the least cost path analysis below.


C: Methodology procedures for Least Cost Path Analysis

The least cost path is based on cost values related to MCE factors. It does not refer to the actual metric distance values nor monetary costs. This means that, the analysis for the algorithm of this path considers MCE factors mentioned above where by the path will be avoiding high risk areas and go through less risky areas and hence guarantee safety of people who choose to use these paths during an emergency. Procedures taken to calculate and allocate the Least cost path are illustrated below:

  • reclassify the MCE to have a friction value of (0 - 0.5) = friction value 1 (base value) = Good (0.5 - 1) = friction value 10 = Bad. (1 - 2.5) = friction value 100 = Really Bad.

  • Create a new point at an arbitrary point on the map by using Arc Catalogue to create a new point layer file and edit tool to add arbitrary points on the map
  • Perform cost distance analysis from the created point and create cost distance raster and cost back link
  • Select the nearest community centre or hospital and perform cost path analysis by using ArcMap tools and then convert the output raster to vector polylines for better visual representation of the resulted least cost path route.

Maps below demonstrate the least cost paths from a random location an individual could be to the nearest hospital or community center. NOTE: In this project we demonstrated the application of the Least cost path analysis of only two routes. However, we asserted that, this analysis idea could be used by Smart-phone application developers or any other GPS devices developers to develop applications whose algorithms will be including this analysis to display a visual, live and interactive map that could be helpful to individuals to figure out which route to take to get to the nearest safe destination safely from a risky location using their GPS receiver devices. An example of the phone application that could be modified and redesigned to display maps with the option of Least cost path during an earthquake emergency is the iPhone app called QuakeAware.

MAP 4: Least Cost Path from a random point to Nearest CC

MAP 5: Least Cost Path from a random point to Nearest Hospital