Algorithm for heat map?

Question

I have a list of values each with latitude and longitude. I\'m looking to create a translucent heatmap image to overlay on Google Maps. I know there are server side and flash

Answer 1

The basic idea would be to create a grid and project every lat,lng coord to that grid. I would use a 2D array of ints.

The psuedo-code would be:

for each coord
  cell = coord projected to grid
  increment cell value
end

for 0 to # of passes
  for each row
   for each col
     if grid[row,col] > 0 then
       grid[row,col] += 1
       increment_adjacent_cells(row, col)
     end
   end
  end
end

So, the idea is that the higher the int value, the hotter that cell is. increment_adjacent_cells should increment the values in all 8 adjacent cells.