Below is the syntax highlighted version of PUHeatMap.java.
/* Christopher Moretti * cmoretti * P01A/P06 * * takes resolution and map filename on CL * reads lat/lon coordinates from StdIn * prints total points and filled cells to StdOut * draws colored heatmap on StdDraw * * Dependencies: StdIn, StdOut, StdDraw */ public class PUHeatMap { // sets the pen color according to the ratio of // points at this location (here) versus all points private static void setColor(int here, int all) { StdDraw.setPenColor(StdDraw.BLUE); if(here > .001*all) StdDraw.setPenColor(StdDraw.YELLOW); if(here > .003*all) StdDraw.setPenColor(StdDraw.ORANGE); if(here > .005*all) StdDraw.setPenColor(StdDraw.PINK); if(here > .007*all) StdDraw.setPenColor(StdDraw.MAGENTA); if(here >= .009*all) StdDraw.setPenColor(StdDraw.RED); } public static void main(String[] args) { //resolution int N = Integer.parseInt(args[0]); // map filename String PHOTO = args[1]; // map extremes double minX = -74.66443; double minY = 40.33855; double maxX = -74.64564; double maxY = 40.35281; // set scale from 0->N in both dimensions // and draw picture centered and scaled. StdDraw.setXscale(0, N); StdDraw.setYscale(0, N); StdDraw.picture(N/2, N/2, PHOTO, N, N); // matrix of possible grid locations int[][] arr = new int[N][N]; // counters for printed statistics int totalPoints = 0; int nonZeroCells = 0; // read in all lat/lons from StdIn while(!StdIn.isEmpty()) { double y = StdIn.readDouble(); double x = StdIn.readDouble(); // error-checking code, you don't need this, we guarantee it! if(x > maxX || x < minX || y > maxY || y < minY) { StdOut.println("Outside map: ("+x+","+y+")"); } else { // scale lat/lon to 0-1 double yCoord = (y - minY)*(1/(maxY-minY)); double xCoord = (x - minX)*(1/(maxX-minX)); // increment grid cell count and total count arr[(int)(xCoord*N)][(int)(yCoord*N)]++; totalPoints++; } } // for all filled grid cells, set the color based // on the value then draw a circle at that cell StdDraw.show(0); for(int i = 0 ; i < N; i++) { for(int j = 0 ; j < N; j++) { if(arr[i][j] > 0) { nonZeroCells++; setColor(arr[i][j], totalPoints); StdDraw.filledCircle(i,j,.01*N); } } } StdDraw.show(); // print statistics StdOut.println("Total points: "+totalPoints); StdOut.println("Filled cells: "+nonZeroCells); } }