I have several data sets that represent a type of activity within a specific geographic boundary. Each heatmap I create shows the relative activity spread nicely, but I have been frustrated in my attempts to calibrate absolute levels between each of the heatmaps. I am wanting to reveal not only the shifting in relative activity spatially, but also in terms of absolute activity overall.
For example, I'd like to create two heatmaps, say day versus night, and show how the activity moves from, say, city center to suburbia. But I also want to see if the activity is half as much or twice as much during the daytime peaks as compared to the nighttime peaks.
The data I have are a series of lat/lon pairs with a value ranging from 0 to 50, one value per dot:
Here is the second set of data, same idea, except that the maximum values only reach 30, not 50. I am trying to know how to make sure that the color for maximum in the second show that the activity not only moved, but is half the amount (quantitatively) than the first data set:
I am also having some confusion about the differences bewteen heatmap plugin and the heatmap style: how do they differ? I am on QGIS 2.8 (Gentoo Linux). The style seems to work, but then gets corrupted, and the heatmap plugin seems kaput (it worked in 2.6...)
Here are the settings I used in 2.6 that worked (but do not at all in 2.8):
Here is a dialog from the Heatmap style I tried to use. This works in 2.8 but gets corrupted if I add other layers:
If it's not obvious yet, GIS is not my specialty.