Thursday, 14 December 2017

Data visualisation: Plotting USGS earthquakes

This post makes use of USGS's live feed of earthquakes. The feed is plotted on a Leaflet map to visualize the data. Leaflet is a javascript library for interactive maps (http://leafletjs.com/). The advantage is that it consumes Geojson well.  



Feeds are categorised into all quakes and significant ones. The app's hourly feed is updated continuously for new data. When new data is available the map is updated. For each point of interest a leaflet layer group is utilised. This holds a circular marker layer and a place holder. A popup layer is also added which displays a text with the title from geojson. This title includes magnitude and location of the quake. All layer groups are added to the map's layer group. This allows individual layers associated with a point to be update or removed when data is updated.

Although all earth quakes are not significant, from the data is clear that earthquakes are more common in plate boundaries and fault lines (not surprising but nice to visualise). Switching to a weekly or monthly view makes vulnerable locations apparent.

Significant quakes are also seen in daily, weekly and monthly basis. Adding filters to query on Magnitude or changing the circle marker circumference based on magnitude would be good. However, significant earthquakes are far less in number and are shown separately in the app. Also to be noted is that, leaflet slowed down when a lot of layers were used for each point to support individual point updates. It also eases out when the map is just cleared and updates are added.

Tools:

Python 3.5.3
Django 1.10
Postgresql
Bootstrap 3.3.7
Leaflet 1.2.0
Javascript, JQuery
Geojson
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