I'm working on a Java program that processes some data and generates a Heat Map to display the results. This program takes a target area and divides that area into a grid, which for the sake of testing each cell is 1NM by 1NM. I generate a KML file and that for each cell in the grid is represented by a polygon and the polygon is coloured based on the value of the cell. However with the volume of data that may be used, I am worried that Google Earth may not be able to handle the amount of polygons being drawn(hundreds of polygons).

I have heard that pictures are less resource heavy for Google Earth, so is there a way of generating a image(like .jpg or .png) in Java of the Heat Map and overlaying it in Google Earth. The center of the cell is know and the 4 corners are calculated, with each cells RGB and hex value known. I'm using Geotools and JAK as libraries for this project. Any help would be greatly appreciated.