Interactive Data Visualization — Kerala Flood 2018
“ Giving form to Data is Visualization”
A graphical or pictorial representation of data is Data Visualization. It enables us to see analytics presented visually, so we can grasp difficult concepts or identify new patterns. Making interactive visualization can take the concept a step further by using technology to drill down into charts and graphs for more detail, interactively changing what data we see and how it’s processed.
The Project
As part of the Interactive Data Visualization, I have created visualization for the recent floods that happened in Kerala. I had to collect data from different sources regarding the calamity, segregate them, find a story/theme from it and at then choose a proper tool for the visualisation.
Kerala Flood 2018
Kerala is small state which is situated at the south-western part of India and well-known as a beautiful tourist destination. Villages, cities and towns in Kerala are more dispersed geographically compared to other Indian states. Many of the urban area lies on the coastline of the state.
In July 2018, severe floods affected Kerala due to unusually high rainfall during the monsoon season. It was the worst flooding in Kerala in nearly a century. Over 483 people died and at least a million people were evacuated.
35 out of the 54 dams within the state were opened for the first time in history. Heavy rains in districts like Wayanad and Idukki in Kerala caused severe landslides and have left the hilly districts isolated. One-sixth of the total population of Kerala had been directly affected by the floods and related incidents. It is the worst flood in Kerala after the Great Flood of 99 that happened in 1924.
Story for Data Visualisation
After going through many articles and videos about the Kerala flood, I collected some data and segregated them. Data regarding flood affected areas, dates of opening of dams, quantity of water released, rain and landslides, social media activities etc.
Among all this, the data which I choose was about the altitudes of different towns and cities in Kerala. The information contained the name of each and every towns and city in Kerala, postal code, latitude and longitude etc.
“Detecting the areas which have high chances of flood and landslides through visualizing altitude data”
This visualization tries to relate altitudes of different places and their susceptibility to floods. This visualization is helpful to understand places which are prone to floods and related calamities.
Tools and Exploration
For executing the visualisation, I was looking for a tool that can be interactive and that could represent 3D content on a map based on its latitude and longitude values. Representing altitudes on a map requires using 3D as it need to convey information about location and altitude of the place.
Software’s such as Tableau, Microsoft Excel, Flourish, Mapbox, Uber Engineering etc. were explored. Finally Microsoft Excel was chosen as the tool for the project. Microsoft Excel has the features called Power View and Power Map and contains 3D interactive visualisation templates. The templates had stacked & clustered column, Bubble, Heat map and Choropleth as options. Stacked column was chosen for the Kerala Flood Data Visualisation project.
Microsoft Excel made the job easier. The data was cleaned and categorized in Microsoft Excel spreadsheet. I got postal code data about all cities, towns and villages in Kerala. To get altitude values, I had to find the latitude and longitude values from the name of the cities. Geocoding plugin in Google sheets returns latitude and longitude values of a city from the name string. From the latitude and longitude values, I got the altitude of the places from this website. Power Map plugin in Excel will automatically recognise the places through the postal code (Zip Code). After the 3D column option is selected, the altitude data is dragged in to the height option of the column.
The visualization in Power Map gives output as a video or an image file. And also to know the details of any individual place, the user has to keep the cursor on the extruded bar in the map. Power Map also makes it easy for the user to navigate through the data. When user looks at the visualisation, it is easy to get an overall idea about the altitudes of different places in Kerala.
Output
The extruded columns is providing a clear idea about the altitude pattern of kerala. We can observe that the land near to the sea has elevation equal to or less than the sea level and when moving towards north east side the altitude is increasing.
I identified districts which were worst hit by landslide and flood and mapped it with their altitude values. It is clear from the visualization that two districts, Idukki and Wayanad, which were hit by landslides have high altitude values. Some of the low lying areas were hit by flood whereas some were unaffected.
