UPDATE: I just upgraded to QGIS 2.4 along with upgrading my OS to Linux Mint 17, and the problem described below no longer seems to an issue. Continue reading Issue with QGIS DB Manager SQL Window
Hexbinning is a method for visualizing point data when many similar values mean there is a lot of overplotting. Although it originated in the data visualization field as a an enhancement to the traditional XY scatterplot, within the last few years hexbinning has been used more and more in cartography. (See this great blog post by Zachary Forest Johnson which traces this history and explains how to create hexbin maps using D3.js.)
I wanted to map police stops under the NYPD Stop and Frisk program (official source, easier to use version from NYCLU), but at city or borough scale, this just looks like a continuous carpet of dots. Visualizing that kind of dense point data is exactly what hexbinning is for.
Continue reading Hexbinning