title: NW Extension and Agent Navigation
body: <p>I'm trying to work out how to implement agent navigation.  I have set up my model to sprout nodes on every "floor" patch in my evacuation model. i have also linked the turtles to respective nodes. What i'm trying to do is have evacuees plot a path towards the exit and execute evacuation simultaneously. The png image i have used is a basic floorplan with a white floor, and black walls/obstacles, i figured by sprouting nodes on the white floor the agents will automatically navigate around said obstacles. I understand this is possible using nw extension however i have failed in incorporating it into my model. I have looked at the link walking turtle example and still can't figure this out. Has anyone got any advice as to how this can be done based on the code below? or any advice on how to incorporate path-finding in general? Any help would be much appreciated.</p>
  
  <pre><code>breed [nodes node]
  breed [cells cell]
  breed [evacuees evacuee]
  
  evacuees-own
   [ target   
    direction  
   ]
  
  
  to setup
  clear-all
  
  set-default-shape turtles "person";
  import-pcolors "floorplan.png"
  
  
  ask n-of evacnum patches with [pcolor = white]
     [
       sprout-evacuees 1 [
       set size 7
       set color green
      ;set speed 1 + random-float 1.5
  
  
    ifelse random 2 = 0
      [ set direction 1     
         ]
     [ set direction -1    
        ]
  
  
  
  
    ]
    ]
  
  
    ask patches with [ pcolor = white ] [
  
   sprout-nodes 1 [
    set size 0.5
    set shape "circle"
    set color grey
    ]
   ]
  
   ask nodes [
   create-links-with turtles-on neighbors4 [
    set color grey
   ]
   ]
  
  ask patch 146 199
   [
  
    sprout-cells 1 [
      set size 1.5
      set shape "box"
      set color yellow
    ]
    ]
  
   ask evacuees
   [ set target one-of min-n-of 5 nodes [distance myself]
   face target
    ]
  
  
    reset-ticks
    end
  
    to go
    move
    tick
    end
  
    to move
    ask evacuees
  
     [
      walk
     forward 0.25
     if distance target &lt; 0.2
     [ set target one-of min-n-of 5 nodes [distance myself]
     ]
     face target
      ]
  
  
  
     end
  
  
     to walk
      if not wall? (90 * direction) and wall? (135 * direction) [ rt 90 * 
     direction ]
     while [wall? 0] [ lt 90 * direction ]
     end
  
     to-report wall? [angle]
     report black = [pcolor] of patch-right-and-ahead angle 1
     end
  </code></pre>