Display crash data points in place detail screen

[lydiascarf]

Criteria:

• When you go to a place detail screen, you should be able to toggle on a new layer for crashes
• The crashes should then show up as markers
• The markers should cluster as you zoom out, and the clusters should display a count
• The markers should handle overlapping data points well (same coords)
• The markers should look different based on the fatality type

Proposed implementation:

• This leaflet plugin should get you clustering, tooltips, and clustering
  • see this demo of the above plugin
• Use the following columns to determine which marker appearance to use
  • Bicycle fatality (A_PEDAL_F=1)
  • Pedestrian fatality (A_PED_F=1)
  • Other fatality (A_PEDAL_F=2 and A_PED_F=2)

Open questions:

• how should we label other fatalities, i.e. non-bike non-pedestrian fatalities? Is other okay, or can we get a more descriptive label?

[lydiascarf]

@philippschmitt you were asking about the plugin we'll use for clustered points. I think we'll use this one. You can see a demo here. There are some overlapping points in this demo, and I think the behavior there looks good. When I click on an overlapping set of two points, they separate out with little line connectors so I can then reach either one for a tooltip.