I cannot help myself, I promised to step down and don't compete for a time... but I did it again I participated to the Ironviz
Here the details about this competitition : Make a splash in Iron Viz Water | Tableau Public
First I wondered what I subject I could possibly pick, and how to represent it. Because the subject was Water, I decided to do a viz on the Seine, or more precisely about the Seine's floods.
To do so I need maps, a lot of maps. This blog post will explain how to create those maps in Tableau, nothing fancy though.
1- Paris altitude map : This is probably the easier
This map shows some of the Paris monuments in an elevated map. I collected the information Google earth pro and I then copied them in Excel,
Once you connect Excel to tableau, this view is a dual axis : one drawing the profile and the other one representing the monuments. I tried to find the most similar icons possible and work out the colour. Even if it not always easy without a designer ( who draw them for you), the results is satisfactory. I had to modulate the position of the icons so they appear on top of the line.
2-The Seine profile
This map is done by connecting a shapefile ( from https://www.data.gouv.fr/fr/datasets/dcpsl-hydrographie-1820-fleuves-rivieres/) for the Seine's mapping and an Excel file for marking the exact beginning and end of the Seine ( in order that the comments point out exactly to them). A dual axis does the trick
For the first one, the geometry field in details, and for the second the departure and arrival.
The Map is a traditional Tableau map with a light style and without base to be able to colour the background.
To illustrate the fact that Paris is divided by the Seine in two parts, I create in Tableau this custom map. Having the postal code, I simply create a group of the different postal code matching the "right part" of the river and the ones matching the "left part". This group can then be used.
4-Joining two shapefiles
In the journey of my viz, I wanted to compare the 1910's floods (dark blue) with the actual prevision for the same level of flood ( light blue). But I had two shapefiles and I don't have any software able to do the work. But with the new feature of Tableau, I can join the two shapefiles with the intersects option. Et voila ...
To finish, the last map, I used in my viz is a join of differents geo datesources one for the floods and one for the monuments represented as the points. But here the difficulty comes from the fact that I had to create the latitude and longitude for the monuments. I had the streets localisation, but as you may know, I couldn't use it in Tableau. Tableau cannot (yet) to go below the postcode level.
So I connect my datasource to Alteryx, and in two simple steps ( I am an Alteryx beginner) I could use their geocoder to convert my streets in gps location, and used it in my viz.
Concerning the design of the full dashboard, I just choose to have a clear and epurate design only grey and of course blue ( for the water theme).
Hope you like it.
link to the viz : Tableau Public
This viz has been done with free copyright icons and open data coming from the following websites :
- icons : www.colourbox.com
- Zouave info : https://fr.wikipedia.org/wiki/Zouave_du_pont_de_l%27Alma
- protections in case of floods :
- Other : wikipedia of course
August 25th 2018