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When I use this I get an undefined error. latitude is undefined.

var arDrone = require('ar-drone');
var droneClient = arDrone.createClient();
droneClient.config('general:navdata_demo', 'FALSE'); // get back all data the copter can send
droneClient.config('general:navdata_options', 777060865); // turn on GPS

droneClient.on('navdata', function(navdata) {
   console.log(navdata.gps.latitude + ', ' + navdata.gps.longitude);
   // do stuff with the GPS information....
});
droneClient.takeoff(); .....

However if I change 1 line I can get back all gps data. 

console.log(navdata.gps);

Why can't I just get back the latitude data specifically? 

var arDrone = require('ar-drone');
var droneClient = arDrone.createClient();
droneClient.config('general:navdata_demo', 'FALSE'); // get back all data the copter can send
droneClient.config('general:navdata_options', 777060865); // turn on GPS

droneClient.on('navdata', function(navdata) {
   console.log(navdata.gps);
   // do stuff with the GPS information....
});
droneClient.takeoff(); .....
Kevin Hunkovic
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  • please provide the exact error message. Maybe also the output of `console.log(navdata.gps);` It seems like maybe latitude isn't a property accessible using the dot operator. – Jim U Mar 29 '17 at 20:16
  • C:\data>node gpsLog.js C:\data\gpsLog.js:8 console.log(navdata.gps.latitude + ', ' + navdata.gps.longitude); ^ TypeError: Cannot read property 'latitude' of undefined at Client. (C:\data\gpsLog.js:8:27) at emitOne (events.js:96:13) at Client.emit (events.js:188:7) at Client._handleNavdata (C:\data\node_modules\ar-drone\lib\Client.js:194:8) at emitOne (events.js:96:13) at UdpNavdataStream.emit (events.js:188:7) at UdpNavdataStream._handleMessage (C:\data\node_modules\ar-drone\lib\navdata\UdpNavdataStream.js:73:10) – Kevin Hunkovic Mar 29 '17 at 21:33
  • this code came from another article suggesting it does work. http://stackoverflow.com/questions/24170884/get-gps-data-from-ar-drone-2-0 – Kevin Hunkovic Mar 29 '17 at 21:35
  • I just gave something a try. droneClient.on('navdata', function(navdata) { try {     console.log(navdata.gps.latitude + ', ' + navdata.gps.longitude); } catch(err) {     console.log(err.message); } – Kevin Hunkovic Apr 08 '17 at 22:04

1 Answers1

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you have to call gps first, use "if(navdata.gps){}, then put the gps property on it. but the result is 0. even using the number to activated the gps. the value of latitude and longitude will be "0".

Yusril Dewantara
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