import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.StringTokenizer;
    
    // loads dem ascii file
    public void loadDEM() {
        BufferedReader in = null;
        System.out.println("reading filename = "+filename);
        try {
            in = new BufferedReader(new FileReader(filename));
            cols = Integer.parseInt(in.readLine().trim());
            rows = Integer.parseInt(in.readLine().trim());
            System.out.println("reading: rows = " + rows  + "  cols = " + cols);
            dem = new double[rows][cols];
            
            
            for (int i=0; i<rows;i++) {
                StringTokenizer line = new StringTokenizer(in.readLine());
                int nc = 0;
                while (line.hasMoreElements()) {
                    dem[i][nc] = Double.parseDouble(line.nextToken());
                    nc++;
                }
                if (nc != cols) System.out.println("Warning: cols = "+cols+"   nc = "+nc);             
            }
        } catch(IOException e) {
            System.out.println("Error reading file "+ filename);
        }
        System.out.println("finished reading data");
        scale();
        System.out.println(toString());
    }