grab radar data from the radarmatic API, convert to cartesian coordinates, and output as CSV, and then a Processing file to render it

radar.pde

/*
 * Render the data output by radar.py as an image.
 */

void setup() {
  size(700,700);
  background(255);
  stroke(0);
  smooth();
  scale(2,2);
  translate(200,200);
  
  String lines[] = loadStrings("radar.csv");
  println("there are " + lines.length + " lines");
  for (int i=0; i < lines.length; i++) {
     String[] cols = split(lines[i],',');
     float x = float(cols[0]);
     float y = float(cols[1]);
     float z = float(cols[2]);
     
     stroke(z*50);
     point( x, y );
   }
   
   save("radar.png");
 }

void draw() {
  
}

radar.py

from urllib import urlopen
import json
from math import radians, sin, cos

fpin = urlopen( "http://radarmatic.com/kokx.json" )
fpout = open( "radar.csv", "w" )
fpout.write( "x,y,z\n" )

radarjson = fpin.read()

radar = json.loads( radarjson )

for radial in radar['layers'][0]['radials']:
    theta = radial['start_angle']
    
    for i, val in enumerate( radial['range_bins'] ):
        r = i+1
        
        x = cos(radians(theta))*r
        y = sin(radians(theta))*r
        z = val
        
        fpout.write( "%s,%s,%s\n"%(x,y,z) )
        
fpout.close()