Sunday 3 June 2018

Simultaneous gantt objects (2018.1 update of using pivot with contracts)

My second post more than a year ago looked at how we find simultaneous gantt type objects. While the method for data preparation still stands, the final plot can be refined a bit thanks to the latest tableau update, the step line type
This now gives a more realistic depiction of the number of concurrent objects and how they change, as it is going to be a step change through integer values rather than a ramp up.

Friday 1 June 2018

Layering filled maps and polygons on map (2018.1 update)

I wrote about this technique more than a year ago and it was one of my more popular posts, thanks to a tweet by zen master Chris Love. It is time to update the particular example as version 2018.1 finally brings generated Latitude and Longitude closer to Latitude and Longitude already in the dataset.

We start by UNIONing our two sources, the polygon source having latitude and longitude, the mark source having a field that can be interpreted as a filled map.

 We then use the new trick of putting generated latitude and longitude on the axis, with source latitude longitude in the level of detail for the polygon layer. In the past I would import the filled map source, generate the latitudes longitudes, export crosstab to excel, save as csv, and do a union with the polygon csv. No longer necessary as of 2018.1.
Now all that is required is dual axis to overlay the polygon over the filled map.