ISS608 2017-18 T3 G2 Assign ChenYanchong Visualization

ISSS608 Visual Analytics Vast Challenge Mini Challenge 2

Overview

Data Preparation

Visualization

Answer

Feedback

The complete story board for this visualisation is available through Chen Yanchong's Tableau Public
This page will give a brief introduction of how the story board was prepared

Preparation of worksheets

There are total 11 worksheets are used.

1. map

Purpose of this worksheet: making use of the map and using the location information properly

Steps to take:

1. Creating a excel worksheet named location with three columns inside it, location, Xcoord and Ycoord
2. Adding a background map in Tableau
3. Using annotation to get the coordinate of each location on the map
4. Using the prepared data table to left join the location table by the column "location"

2. measure count overall

Purpose of this worksheet: to should the tendency from the start to the end

Steps to take:

1. Create a calculated field measure count , using formula : COUNTD([Measure])
2. Create a calculated field first or last , using formula: FIRST() == 0 OR LAST() == 0
3. Drag sample date to the column shelf, and measure count to row shelf
4. first or last and location as filter, and choose True only
5. measure count on row shelf again, and choose dual axis
6. location on color card, measure count and location on label card

3. measure count detailed

Purpose of this worksheet: showing more detailed measure count than the slope chart above

Steps to take:

1. Duplicate the slope chart
2. Remove first or last from filter

4. measure value per loc

Purpose of this worksheet: using with the map to perform point source

Steps to take:

1. Drag sample date to column shelf and drill it down to month granularity
2. Drag location and measure to row shelf in order
3. Put value on row shelf and choose average as aggregation method
4. Add value to color card and choose average as aggregation method
5. Drag location and measure to filter

5. measure value trend by year

Purpose of this worksheet: how single measure changes in each location by year

Steps to take:

1. sample date on column shelf and drill down to month
2. Put value on row shelf and choose average as aggregating method
3. Choose area for marks
4. Insert measure in title

6. measure value

Purpose of this worksheet: giving more intuitive feeling of the difference of single measure between the start year and the end year

Steps to take:

1. Duplicate the second slope chart
2. Add measure on filter
3. Double click the title and insert measure on the title
4. in the tooltip card, format it a bit and insert above chart to drill down more details

7. heat map

Purpose of this worksheet: using heatmap for the convenience of comparison and obtain more detail time series analysis

Steps to take:

1. Select measure to column shelf and location to row shelf
2. Drag sample date on column shelf and drill it down to month
3. Drag month to row shelf
4. Apply location and measure as filters
5. Put average value on color card

8. seasonality trend

Purpose of this worksheet: to discovery seasonality patterns

Steps to take:

1. Duplicate the measure value by year trend worksheet
2. Reverse the position of year and month

9. percentage diff

Purpose of this worksheet: comparing each location against all

Steps to take:

1. Create calculated field avg_across_all by formula : { FIXED YEAR([Sample Date]), [Measure]:AVG([Value])}
2. Create calculated field pct_diff_with_all by formula: ({ FIXED YEAR([Sample Date]), [Location], [Measure]:AVG([Value])} - [avg_across_all])/[avg_across_all]
3. Create calculated field increased? by formula: IF [pct_diff_with_all] > 0 THEN 'higher' ELSEIF [pct_diff_with_all] < 0 THEN 'lower' ELSE 'equal' END
4. location and pct_diff_with_all on column shelf
5. sample date on row shelf
6. measure and location on filter
7. increased? on color card

10 0.3 principle

Purpose of this worksheet: using 0.3 principle to detect the locations are polluted
0.3 principle can see data preparation section for more details

Steps to take:

1. Create calculated field total chemical oxygen demand by formula: IF [Measure]='Chemical Oxygen Demand (Cr)' THEN [Value] ELSEIF [Measure]='Chemical Oxygen Demand (Mn)' THEN [Value] END
2. Create calculated field total oxygen demand by formula IF [Measure]='Biochemical Oxygen' THEN [Value] END
3. Create calculated field oxygen rate by formula AVG([total oxygen demand])/AVG([total chemical oxygen demand])
4. Year of sample date and month of sample date on column shelf
5. oxygen rate on row shelf
6. Year of sample date and location on filter and location on details as well as on color
7. Add a constant reference line on across table with a value 0.3

11. intuitive line graph

Purpose of this worksheet: dividing the worksheet by location to obtain insights easier

Steps to take:

1. Create calculated field col divider by formula : (INDEX()-1)%(ROUND(SQRT(SIZE())))
2. Create calculated field row divider by formula : INT((INDEX()-1)/ROUND(SQRT(SIZE())))
3. Put location on detail and label
4. Put col divider on column shelf and row divider on row shelf, make them computing using location and make them discrete value
5. Drag value on row shelf as well as on color card and on label card
6. Put measure as filter

User Guide for dashboard

Dashboard 1: Water composition changes by year

Dashboard 2: Point source among locations

To filter measures, user can choose from the dropdown menu;
Click the locations on the map the location filter can work on the scatter plot as well;
If user clicked the empty area on the map, all the locations will be selected.