IS428 AY2019-20T1 Assign Tan Sok Yi DataTransformation

IS428 Visual Detective: Crowdsourcing for Situational Awareness

Background

Dataset Analysis and Cleaning Process

Dashboard

Insights

Data analysis and cleaning process

Before creating the visualisation, analysis of the dataset is done to understand the different variables and attributes. One dataset, containing reports of shake intensity and the intensity of the damage in the different areas (buildings, medical, power, road and bridges, sewer and water) in the various neighbourhood, in an interval of 5 minutes. Shake maps were also provided which allowed a better understanding of the coverage of the earthquake.

Geographical data is available in MC2 where a shp file showing the coordinates of the different neighbourhood. This dataset would be useful in creating the visualisation for MC1. For the datasets given, it needs to be clean and process first to prepare the data for the visualization.

Data Cleaning

1. Getting the coordinates of the different locations

Problem 1	Getting the coordinates of the different locations
Issue	Geographical data is needed to create a map visualisation which will be useful in analysing the dataset. However, the exact location of the neighbourhood cannot be plotted as the coordinates of the different locations are not available in the dataset.
Solution	To solve this problem, the data is available as a shp file in MC2 can be used to retrieve the coordinates for the different location. After retrieving the coordinates, a polygon on a map can be created. a. To get the coordinates, we first import the shp file to tableau b. Next, moving to worksheet 1, the longitude and latitude is drag to the column and row respectively. Drag the Geometry to the detail and tableau will automatically generate the map. For the map to show the location id of the different section, drag id to label and we will be able to know the location of the different neighbourhood. c. Click on View Data under Analysis and the data can be exported as a CSV file. d. Click on View Data under Analysis and the data can be exported as a CSV file. e. However, this causes another issue as the size of the polygons become small and becomes the centroid when the background image is added. f. However, this causes another issue as the size of the polygons become small and becomes the centroid when the background image is added.

2. Size of polygons

Problem 2	Size of polygon
Issue	Size of polygon shrinks when background image is added and becomes a a centroid instead
Solution	To solve this problem, we have to grow our own filled maps and transform them into an appropriate geographic coordinate reference system for Tableau to use. Such implementation can be found in https://community.tableau.com/thread/116369. The 2 CSV file that was created via the method provided in the link was kindly provided by my classmate on elearn discussion forum.

3. Transposing of the data

Problem 3	Transposing of the data
Issue	The dataset provides multiple responses collected from different users at the different timestamp. However, based on the structure of the data, it is difficult to analyse the data and apply filters on the visualisation based on the different damage area.
Solution	To solve this issue, we will make use of Tableau Prep to transpose the different columns (buildings, medical, power, roads and bridges, sewer and water and shake intensity) into one column for better analysis. a. Create a new flow by dragging the dataset into Tableau Prep. b. Add a pivot and drag the fields (buildings, medical, power, roads and bridges, sewer and water and shake intensity) to swap the different columns into different rows. c. Add output and the transposed table will be shown. After pivoting the table, the different area is now under one column named “Damage Area” and its respective value is under another column “Damage Value”. Save the file as a CSV file. Then, we will be able to create the respective visualization necessary for the assignment.