I have a point dataset generated from getting the centroid points from a fishnet/polygon grid. I combined these points using a spatial join to give them an attribute of 'pressure' which is an integer value.

In either qgis, postgis or cartodb (i.e. using CSS styling options) is there any way to display these data as a heatmap with the heat generated by the pressure value rather than the point density?

I've already made a map with graduated symbols based on the pressure but i'd like a more traditional heatmap view.

A workaround I had been thinking about was to put a proportional number of points in each polygon in the grid and generating a standard heatmap of point density but this doesn't seem like a very efficient method so I want to rule out other options first.

Another thought I had was to try and draw best fit contour lines and styling them appropriately but I wasn't sure if I could use a point vector input to create contour lines like this.