Hong Kong Access Map

Project website: https://access.hk

This is a preliminary attempt of Geospatial HK to map the wheelchair accessibility hotspots in the city. Objective of this map is to pinpoint the area that is not optimally designed for wheelchair users or area that has natural limitation that is unfavourable to the wheelchair users. This study uses the 3D Pedestrian Network data set from CSDI portal.

Method

We define hexagon grid over the city, each grid is 1-Hectare large.

For each hexagon grid, we set its center as the starting point and searching for the shortest path reaching surrounding hexagon grid within a 400m radius. For each start end pairs there are 2 paths searched, one using the general pedestrian path, and the other one considering the wheelchair obstacles indicated in the 3DPN data set.

Then, we will calculate the barrier ratio which is

length of wheelchair path / length of general pedestrian path

For all end points of a starting point, and highest ratio will be the index of that starting point. The hexagon grid will be displayed in red if the index exceed 1.5, the higher the index and deeper the color of the grid.

When click on the hexagon grid, detail routes will be displayed, the blue one is general pedestrian path, the red one is the wheelchair access path, it has to take longer way because there is wheelchair obstacle such as staircase in between the general path.

We found that some wheelchair path is unreasonably longer than the general path, one of the reason is the incomplete accessible path data in the 3DPN data set, especially those semi-open public access allowing wheelchair to pass through. Beware of that this is just a preliminary study at the moment and for reference only and Geospatial HK bares no obligations on the correctness and completeness of the data set. We will improve the qualify of the map over time.

One of the future enhancement is to add the verification mechanism or site visit /Google Street Map cross checking capability so that public can verify the hotspots on the map. We also want to work with the corresponding stakeholders in the society to extend the usability of this map.

You can download a high resolution printable version here.

Thanks.