Description: A method to conditionally filter by parameter ESRI Shapefiles converted to Tableau Ready Polygon Mark Type by editing ESRI SHP DBF, merging, and then using Richard Leeke's shapetotab.
This method allows multiple SHP files to be analysed; this is a small example as a proof of concept; but it's possible to scale this up (i.e. ZCTA, Census Tracts, Congressional Districts, State/Province, Countries). See example here.
In this example: NYC Fire, Police, Health and Schools.
Dual-axis used only to label foreground polygon mark type.
Tableau Version: 7, but for large polygon sets with marks above 4.3 million use Tableau 8.1 64 bit
Original Author: Allan Walker, data via NYC Planning "Bytes of the Big Apple"