# A Flight Control System to move icon in World Map

**URL:** <https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195>\
**Category:** Dashboard\
**Created:** [14 December 2022 14:40 UTC](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195 "2022-12-14T14:40:36Z")\
**Posts on this page:** 20\
**Page:** 1

<div class="post-metadata">

**Author:** ![Scorpio\_93](https://avatars.discourse-cdn.com/v4/letter/s/5e9695/32.png) [@Scorpio\_93](https://discourse.nodered.org/u/Scorpio_93)\
**Post date:** [14 December 2022 14:40 UTC](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195/1 "2022-12-14T14:40:36Z")

</div>

Hello all,  
I am trying to make a flight control system in node red. The description of the project/simulation is as follows:

- Inject nodes to show or update the position of UAV in the Map
- A Speed Slider which when the speed is increased will make the UAV move in the map in any direction (for e.g. N,S,E,W)
- Buttons to turn the UAV in any direction as above
- When pressing the button it would also rotate the UAV marker/icon in that direction  
I am confused as to how I can start this project/simulation. Any help or ideas would be appreciated by the forum. My current flow is below:

```auto
[
    {
        "id": "594f4d4bfd9f7699",
        "type": "tab",
        "label": "Flight_Control_SIMULU",
        "disabled": false,
        "info": "",
        "env": []
    },
    {
        "id": "319ff3a15befbaa7",
        "type": "ui_worldmap",
        "z": "594f4d4bfd9f7699",
        "group": "b4ebae93d455bbc5",
        "order": 1,
        "width": 9,
        "height": 10,
        "name": "",
        "lat": "48.80",
        "lon": "13.50",
        "zoom": "",
        "layer": "OSMC",
        "cluster": "0",
        "maxage": "",
        "usermenu": "hide",
        "layers": "hide",
        "panit": "true",
        "panlock": "false",
        "zoomlock": "false",
        "hiderightclick": "true",
        "coords": "deg",
        "showgrid": "false",
        "showruler": "false",
        "allowFileDrop": "false",
        "path": "/worldmap",
        "overlist": "DR,CO,RA,DN,AC,HM",
        "maplist": "OSMG,OSMC,EsriC,EsriS,EsriT,EsriDG,UKOS",
        "mapname": "",
        "mapurl": "",
        "mapopt": "",
        "mapwms": false,
        "x": 1100,
        "y": 40,
        "wires": []
    },
    {
        "id": "01732bfeeaa6afce",
        "type": "ui_text_input",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "label": "Initial Lat Position",
        "tooltip": "",
        "group": "b4ebae93d455bbc5",
        "order": 2,
        "width": 6,
        "height": 1,
        "passthru": true,
        "mode": "number",
        "delay": "100",
        "topic": "lat",
        "sendOnBlur": true,
        "className": "",
        "topicType": "str",
        "x": 210,
        "y": 120,
        "wires": [
            [
                "bb2883299b8bc021"
            ]
        ]
    },
    {
        "id": "2aeed1b10c6c1515",
        "type": "ui_button",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "group": "b4ebae93d455bbc5",
        "order": 3,
        "width": 2,
        "height": 1,
        "passthru": false,
        "label": "Set",
        "tooltip": "",
        "color": "",
        "bgcolor": "",
        "className": "",
        "icon": "",
        "payload": "",
        "payloadType": "str",
        "topic": "set",
        "topicType": "str",
        "x": 90,
        "y": 200,
        "wires": [
            [
                "bb2883299b8bc021"
            ]
        ]
    },
    {
        "id": "bb2883299b8bc021",
        "type": "function",
        "z": "594f4d4bfd9f7699",
        "name": "function 1",
        "func": "var data1 = flow.get(\"data1\") || 0;\nvar data2 = flow.get(\"data2\") || 0;\nvar data3 = flow.get(\"data3\") || 0;\n//var data4 = flow.get(\"data4\") || {value:0,max:50,min:0};\n\nif(msg.topic == \"lat\"){\n data1 = msg.payload;\n flow.set(\"data1\", data1);\n return msg;\n}\n\nif(msg.topic == \"lon\"){\n data2 = msg.payload;\n flow.set(\"data2\", data2);\n return msg;\n}\n// Set Altitude\nif(msg.topic == \"alt\"){\n data3 = msg.payload;\n flow.set(\"data3\", data3);\n msg.payload = {\n \"name\": \"SIMULU\",\n \"alt\": data3 + \"m\",\n \"layer\": \"gps\"\n }\n return msg;\n}\n\n// Speed Calculation\nvar data_lat1 = data1 * Math.PI / 180;\nvar data_lon1 = data2 * Math.PI / 180;\nvar data_lat2 = 0;\nvar data_lon2 = 0;\nlet dlat = data_lat1 - data_lat2 ;\nlet dlon = data_lon1 - data_lon2;\nlet z = Math.pow(Math.sin(dlat / 2),2)\n + Math.cos(data_lat1) * Math.cos(data_lat2)\n * Math.pow(Math.sin(dlon / 2),2);\nlet c = 2 * Math.asin(Math.sqrt(z));\nlet r = 6371;\nlet distance = c * r;\nvar time = 3600;\nvar speed = distance / time;\n\n//Set Speed\nif(msg.topic == \"speed\"){\n \n msg.payload = {\n \"name\": \"SIMULU\",\n \"speed\": speed + \"kn\",\n \"layer\": \"gps\"\n }\n return msg;\n}\n\n// Up Button Config\nif (msg.topic == \"up\") {\n data1 = data1 + 1;\n var speed_up = speed + 0.1;\n var alt_up = data3 + 0.1\n msg.payload = {\n \"name\": \"SIMULU\",\n \"lat\": data1,\n \"layer\": \"gps\",\n \"speed\": speed_up.toFixed(2) + \"kn\",\n \"alt\": alt_up + \"m\"\n }\n node.warn(data1);\n}\n\n//Down Button Config\nif(msg.topic == \"down\"){\n data1 = data1 - 1;\n var speed_down = speed - 0.1;\n var alt_down = data3 - 0.1;\n msg.payload = {\n \"name\": \"SIMULU\",\n \"lat\": data1,\n \"layer\": \"gps\",\n \"speed\": speed_down.toFixed(2) + \"kn\",\n \"alt\": alt_down + \"m\"\n }\n}\n\n//Left Button Config\nif(msg.topic == \"left\"){\n data2 = data2 - 1;\n var speed_left = speed - 0.01;\n var alt_left = data3 - 0.01;\n msg.payload = {\n \"name\": \"SIMULU\",\n \"lon\": data2,\n \"layer\": \"gps\",\n \"speed\": speed_left.toFixed(2) + \"kn\",\n \"alt\": alt_left + \"m\"\n }\n}\n\n//Right Button Config\nif(msg.topic == \"right\"){\n data2 = data2 + 1;\n var speed_right = speed + 0.01;\n var alt_right = data3 + 0.01;\n msg.payload = {\n \"name\": \"SIMULU\",\n \"lon\": data2,\n \"layer\": \"gps\",\n \"speed\": speed_right.toFixed(2) + \"kn\",\n \"alt\": alt_right + \"m\"\n }\n}\n\n//Set Button Config\nif(msg.topic == \"set\"){\n msg.payload = {\n \"name\": \"SIMULU\",\n \"lat\": data1,\n \"lon\": data2,\n \"alt\": data3 + \"m\",\n \"speed\": speed.toFixed(2) + \"kn\",\n \"icon\": \"plane\",\n \"iconColor\": \"black\",\n \"layer\": \"gps\",\n \"popped\": true\n }\n \n}\nreturn msg;",
        "outputs": 1,
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [],
        "x": 580,
        "y": 140,
        "wires": [
            [
                "2cb3acd121995f56",
                "14927396080798d3",
                "0b8c558142c13b6e"
            ]
        ]
    },
    {
        "id": "0b8c558142c13b6e",
        "type": "debug",
        "z": "594f4d4bfd9f7699",
        "name": "debug 3",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "false",
        "statusVal": "",
        "statusType": "auto",
        "x": 740,
        "y": 200,
        "wires": []
    },
    {
        "id": "2cb3acd121995f56",
        "type": "worldmap-tracks",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "depth": 20,
        "layer": "single",
        "smooth": false,
        "x": 870,
        "y": 40,
        "wires": [
            [
                "14927396080798d3"
            ]
        ]
    },
    {
        "id": "14927396080798d3",
        "type": "worldmap",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "lat": "48.80",
        "lon": "13.50",
        "zoom": "",
        "layer": "OSMC",
        "cluster": "",
        "maxage": "20",
        "usermenu": "show",
        "layers": "show",
        "panit": "true",
        "panlock": "false",
        "zoomlock": "false",
        "hiderightclick": "false",
        "coords": "deg",
        "showgrid": "false",
        "showruler": "false",
        "allowFileDrop": "false",
        "path": "/worldmap",
        "overlist": "DR,CO,RA,DN,AC,HM",
        "maplist": "OSMG,OSMC,EsriC,EsriS,EsriT,EsriDG,UKOS",
        "mapname": "",
        "mapurl": "",
        "mapopt": "",
        "mapwms": false,
        "x": 1100,
        "y": 200,
        "wires": []
    },
    {
        "id": "3f1eed7c26c68aa2",
        "type": "ui_text_input",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "label": "Initial Lon Position",
        "tooltip": "",
        "group": "b4ebae93d455bbc5",
        "order": 4,
        "width": 6,
        "height": 1,
        "passthru": true,
        "mode": "number",
        "delay": "100",
        "topic": "lon",
        "sendOnBlur": true,
        "className": "",
        "topicType": "str",
        "x": 210,
        "y": 160,
        "wires": [
            [
                "bb2883299b8bc021"
            ]
        ]
    },
    {
        "id": "6c78defaf08106ad",
        "type": "ui_slider",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "label": "Altitude",
        "tooltip": "",
        "group": "b4ebae93d455bbc5",
        "order": 6,
        "width": 6,
        "height": 1,
        "passthru": true,
        "outs": "end",
        "topic": "alt",
        "topicType": "str",
        "min": 0,
        "max": "100",
        "step": "0.1",
        "className": "",
        "x": 100,
        "y": 240,
        "wires": [
            [
                "bb2883299b8bc021"
            ]
        ]
    },
    {
        "id": "bf273c3b70b21055",
        "type": "function",
        "z": "594f4d4bfd9f7699",
        "name": "function 2",
        "func": "var data = flow.get(\"data\") || 0;\ndata = msg.payload;\nmsg.payload = msg.payload + global.data3;\nflow.set(\"data\", data);\n\nif(msg.topic == \"alt\"){\n msg.payload = {\n \"name\": \"SIMULU\",\n \"alt\": data,\n \"layer\": \"gps\"\n }\n}\nreturn msg;",
        "outputs": 1,
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [],
        "x": 900,
        "y": 320,
        "wires": [
            [
                "14927396080798d3"
            ]
        ]
    },
    {
        "id": "bd958146f73af5c1",
        "type": "ui_button",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "group": "b4ebae93d455bbc5",
        "order": 11,
        "width": 6,
        "height": 1,
        "passthru": false,
        "label": "up",
        "tooltip": "",
        "color": "",
        "bgcolor": "",
        "className": "",
        "icon": "",
        "payload": "",
        "payloadType": "str",
        "topic": "up",
        "topicType": "str",
        "x": 370,
        "y": 40,
        "wires": [
            [
                "bb2883299b8bc021"
            ]
        ]
    },
    {
        "id": "83cee2bda843d0d2",
        "type": "ui_button",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "group": "b4ebae93d455bbc5",
        "order": 13,
        "width": 6,
        "height": 1,
        "passthru": false,
        "label": "down",
        "tooltip": "",
        "color": "",
        "bgcolor": "",
        "className": "",
        "icon": "",
        "payload": "",
        "payloadType": "str",
        "topic": "down",
        "topicType": "str",
        "x": 370,
        "y": 100,
        "wires": [
            [
                "bb2883299b8bc021"
            ]
        ]
    },
    {
        "id": "03aa2f6ba41795a5",
        "type": "ui_button",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "group": "b4ebae93d455bbc5",
        "order": 15,
        "width": 6,
        "height": 1,
        "passthru": false,
        "label": "left",
        "tooltip": "",
        "color": "",
        "bgcolor": "",
        "className": "",
        "icon": "",
        "payload": "",
        "payloadType": "str",
        "topic": "left",
        "topicType": "str",
        "x": 370,
        "y": 220,
        "wires": [
            [
                "bb2883299b8bc021"
            ]
        ]
    },
    {
        "id": "7347a00f5de4aab0",
        "type": "ui_button",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "group": "b4ebae93d455bbc5",
        "order": 17,
        "width": 6,
        "height": 1,
        "passthru": false,
        "label": "right",
        "tooltip": "",
        "color": "",
        "bgcolor": "",
        "className": "",
        "icon": "",
        "payload": "",
        "payloadType": "str",
        "topic": "right",
        "topicType": "str",
        "x": 370,
        "y": 260,
        "wires": [
            [
                "bb2883299b8bc021"
            ]
        ]
    },
    {
        "id": "d3bc3eb546aebf85",
        "type": "ui_slider",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "label": "Speed",
        "tooltip": "",
        "group": "b4ebae93d455bbc5",
        "order": 8,
        "width": 6,
        "height": 1,
        "passthru": true,
        "outs": "all",
        "topic": "speed",
        "topicType": "str",
        "min": 0,
        "max": "50",
        "step": "0.5",
        "className": "",
        "x": 410,
        "y": 340,
        "wires": [
            [
                "bb2883299b8bc021"
            ]
        ]
    },
    {
        "id": "a333b7c63e423341",
        "type": "ui_spacer",
        "z": "594f4d4bfd9f7699",
        "name": "spacer",
        "group": "b4ebae93d455bbc5",
        "order": 5,
        "width": 2,
        "height": 1
    },
    {
        "id": "b799d5f4abc85aea",
        "type": "ui_spacer",
        "z": "594f4d4bfd9f7699",
        "name": "spacer",
        "group": "b4ebae93d455bbc5",
        "order": 7,
        "width": 2,
        "height": 1
    },
    {
        "id": "a8256bf1a70cbc10",
        "type": "ui_spacer",
        "z": "594f4d4bfd9f7699",
        "name": "spacer",
        "group": "b4ebae93d455bbc5",
        "order": 9,
        "width": 2,
        "height": 1
    },
    {
        "id": "3efcf3a26cf4acb5",
        "type": "ui_spacer",
        "z": "594f4d4bfd9f7699",
        "name": "spacer",
        "group": "b4ebae93d455bbc5",
        "order": 10,
        "width": 8,
        "height": 1
    },
    {
        "id": "7755f33ef2e05f46",
        "type": "ui_spacer",
        "z": "594f4d4bfd9f7699",
        "name": "spacer",
        "group": "b4ebae93d455bbc5",
        "order": 12,
        "width": 2,
        "height": 1
    },
    {
        "id": "0ed7f978998ffa18",
        "type": "ui_spacer",
        "z": "594f4d4bfd9f7699",
        "name": "spacer",
        "group": "b4ebae93d455bbc5",
        "order": 14,
        "width": 2,
        "height": 1
    },
    {
        "id": "db7de98bd68799e3",
        "type": "ui_spacer",
        "z": "594f4d4bfd9f7699",
        "name": "spacer",
        "group": "b4ebae93d455bbc5",
        "order": 16,
        "width": 2,
        "height": 1
    },
    {
        "id": "39d7ca7a70f187c4",
        "type": "ui_spacer",
        "z": "594f4d4bfd9f7699",
        "name": "spacer",
        "group": "b4ebae93d455bbc5",
        "order": 18,
        "width": 2,
        "height": 1
    },
    {
        "id": "87fe331c3fba3f22",
        "type": "ui_spacer",
        "z": "594f4d4bfd9f7699",
        "name": "spacer",
        "group": "b4ebae93d455bbc5",
        "order": 19,
        "width": 8,
        "height": 1
    },
    {
        "id": "b4ebae93d455bbc5",
        "type": "ui_group",
        "name": "UAV Flight Control",
        "tab": "37a720198b072daf",
        "order": 1,
        "disp": true,
        "width": 17,
        "collapse": false,
        "className": ""
    },
    {
        "id": "37a720198b072daf",
        "type": "ui_tab",
        "name": "Flight_Control",
        "icon": "dashboard",
        "order": 2,
        "disabled": false,
        "hidden": false
    }
]

```

---

<div class="post-metadata">

**Author:** ![zenofmud](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/zenofmud/32/316_2.png) [@zenofmud](https://discourse.nodered.org/u/zenofmud)\
**Post date:** [14 December 2022 16:08 UTC](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195/2 "2022-12-14T16:08:30Z")

</div>

As a start, you need to do some research on converting speed and distance into Latitude/Longitude updates from the existing position.

---

<div class="post-metadata">

**Author:** ![Scorpio\_93](https://avatars.discourse-cdn.com/v4/letter/s/5e9695/32.png) [@Scorpio\_93](https://discourse.nodered.org/u/Scorpio_93)\
**Post date:** [15 December 2022 13:46 UTC](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195/3 "2022-12-15T13:46:40Z")

</div>

I found out how to calculate next lat/lon points from distance, bearing and speed. Now the question is, is it possible to show a dynamic movement/slow movement of marker towards the next lat/lon point? If yes, then can I use the inject node for this purpose to show that the marker/icon is moving towards that point?  
Also, if I want to change the direction of the icon while moving to that point using button, how would the flow look like?

---

<div class="post-metadata">

**Author:** ![zenofmud](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/zenofmud/32/316_2.png) [@zenofmud](https://discourse.nodered.org/u/zenofmud)\
**Post date:** [15 December 2022 14:32 UTC](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195/4 "2022-12-15T14:32:44Z")

</div>

> [@Scorpio\_93](#):
>
> is it possible to show a dynamic movement/slow movement of marker towards the next lat/lon point?

sure, write a flow that continually sends the new Lat/Lon values to the world map. You can point the marker by filling in the direction (read the `Help` tab for the `node-red-contrib-web-worldmap` node)

---

<div class="post-metadata">

**Author:** ![Scorpio\_93](https://avatars.discourse-cdn.com/v4/letter/s/5e9695/32.png) [@Scorpio\_93](https://discourse.nodered.org/u/Scorpio_93)\
**Post date:** [19 December 2022 09:00 UTC](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195/5 "2022-12-19T09:00:16Z")

</div>

Hello @zenofmud,  
I can't make up the flow as to how I can send the next Lat/Lon to worldmap via function node and also I would want to use the inject node to send constant values to the worldmap for the market, is there any idea to that?

---

<div class="post-metadata">

**Author:** ![zenofmud](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/zenofmud/32/316_2.png) [@zenofmud](https://discourse.nodered.org/u/zenofmud)\
**Post date:** [19 December 2022 11:41 UTC](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195/6 "2022-12-19T11:41:24Z")

</div>

I was just playing around with a simple map and this flow should give you some ideas

```auto
[{"id":"a6f8a950.69aba","type":"worldmap","z":"a54015d0.bd34b8","name":"","lat":"","lon":"","zoom":"","layer":"OSMG","cluster":"","maxage":"","hiderightclick":"false","coords":"none","path":"worldmap2","overlist":"DR,CO,RA,DN,HM","maplist":"OSMG,OSMC,EsriC,EsriS,EsriT,EsriO,EsriDG,NatGeo,UKOS,OpTop","mapname":"","mapurl":"","mapopt":"","mapwms":false,"x":550,"y":120,"wires":[]},{"id":"14547e0d.18c07a","type":"inject","z":"a54015d0.bd34b8","name":"","repeat":"","crontab":"","once":false,"topic":"","payload":"","payloadType":"str","x":100,"y":120,"wires":[["14a1ce4b.c590fa"]]},{"id":"14a1ce4b.c590fa","type":"function","z":"a54015d0.bd34b8","name":"Add plane to map","func":"var thing = {\n name:\"UAV\", \n lat:51, \n lon:-1.45,\n heading: 0,\n icon: \"plane\",\n iconColor:\"darkred\",\n extrainfo:\"lets fly\"\n};\nmsg.payload = thing;\nflow.set(\"location\", thing)\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":290,"y":120,"wires":[["a6f8a950.69aba","c97d7e0e1cb1bb42"]]},{"id":"cb7979a1.3dec98","type":"comment","z":"a54015d0.bd34b8","name":"Simple map - click inject to send point to map.","info":"Adds a map at http://(your-server-ip):1880/worldmap. \n\nThe `function` node creates an object with some basic properties required to add to a map.","x":230,"y":60,"wires":[]},{"id":"c97d7e0e1cb1bb42","type":"debug","z":"a54015d0.bd34b8","name":"debug 1","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","x":560,"y":180,"wires":[]},{"id":"35ae9e0591fd4ef1","type":"inject","z":"a54015d0.bd34b8","name":"","repeat":"","crontab":"","once":false,"topic":"","payload":"","payloadType":"str","x":110,"y":200,"wires":[["dfd3cb8f541df181"]]},{"id":"dfd3cb8f541df181","type":"function","z":"a54015d0.bd34b8","name":"move plane on map","func":"let empty_thing = {\n name: \"\",\n lat: 0,\n lon: 0,\n icon: \"\",\n heading: 0,\n speed: 0,\n iconColor: \"\",\n extrainfo: \"\"\n};\n\nlet thing = flow.get(\"location\") || empty_thing\n\nif (thing.heading == 0 ) {\n thing.lat = thing.lat + .01\n// thing.lon = thing.lon + .01\n}\n\nif (thing.heading > 0 && thing.heading < 90) {\n thing.lat = thing.lat + .01\n thing.lon = thing.lon + .01\n\n}\n\nif (thing.heading == 90) {\n //thing.lat = thing.lat + .01\n thing.lon = thing.lon + .01\n}\n\nif (thing.heading > 90 && thing.heading < 180) {\n thing.lat = thing.lat - .01\n thing.lon = thing.lon + .01\n}\n\nif (thing.heading == 180) {\n thing.lat = thing.lat - .01\n// thing.lon = thing.lon - .01\n}\n\nif (thing.heading > 180 && thing.heading < 270) {\n thing.lat = thing.lat - .01\n thing.lon = thing.lon - .01\n}\n\nif (thing.heading == 270) {\n thing.lat = thing.lat + .01\n// thing.lon = thing.lon - .01\n}\n\nif (thing.heading > 270 && thing.heading < 360) {\n thing.lat = thing.lat + .01\n thing.lon = thing.lon - .01\n}\n\nmsg.payload = thing;\nflow.set(\"location\", thing)\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":310,"y":200,"wires":[["a6f8a950.69aba","20a868c1617e37cb"]]},{"id":"a3fdd2a4bfb8671f","type":"inject","z":"a54015d0.bd34b8","name":"turn right","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":"","topic":"","payload":"right","payloadType":"str","x":120,"y":260,"wires":[["a769cdb9fe89167c","a002b3e8e8efe1aa"]]},{"id":"a769cdb9fe89167c","type":"function","z":"a54015d0.bd34b8","name":"change direction of plane on map","func":"let empty_thing = {\n name: \"\",\n lat: 0,\n lon: 0,\n icon: \"\",\n heading: 0,\n speed: 0,\n iconColor: \"\",\n extrainfo: \"\"\n};\n\nlet thing = flow.get(\"location\") || empty_thing\nlet heading = thing.heading\n\nif (msg.payload == \"right\") {\n if (heading > 359) { heading = 0}\n heading = heading+5\n} \n\n if (msg.payload == \"left\") {\n if (heading < 1) { heading = 360 }\n heading = heading - 5\n}\nthing.heading = heading\n\nmsg.payload = thing;\nflow.set(\"location\", thing)\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":350,"y":280,"wires":[["a6f8a950.69aba","dce5e5b68ae42c2e"]]},{"id":"20a868c1617e37cb","type":"debug","z":"a54015d0.bd34b8","name":"debug 2","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","x":600,"y":240,"wires":[]},{"id":"dce5e5b68ae42c2e","type":"debug","z":"a54015d0.bd34b8","name":"debug 3","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","x":620,"y":340,"wires":[]},{"id":"59883c41e3fb3e8d","type":"inject","z":"a54015d0.bd34b8","name":"turn left","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":"","topic":"","payload":"left","payloadType":"str","x":110,"y":300,"wires":[["a769cdb9fe89167c","a002b3e8e8efe1aa"]]},{"id":"a002b3e8e8efe1aa","type":"debug","z":"a54015d0.bd34b8","name":"debug 4","active":false,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":320,"y":360,"wires":[]}]

```

Try simplifying your work

---

<div class="post-metadata">

**Author:** ![Scorpio\_93](https://avatars.discourse-cdn.com/v4/letter/s/5e9695/32.png) [@Scorpio\_93](https://discourse.nodered.org/u/Scorpio_93)\
**Post date:** [20 December 2022 10:21 UTC](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195/7 "2022-12-20T10:21:20Z")

</div>

Hello @zenofmud ,  
I played around with your flow and it gave me some ideas. I have created a joystick type buttons that make the UAV/plane turn in the direction listed up,down,right, or left. But I want to add a functionality where if I press any of the button it should also move in that direction not just turn, any idea how to go about that?  
My current flow is as below:

```auto
[
    {
        "id": "01732bfeeaa6afce",
        "type": "ui_text_input",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "label": "Initial Lat Position",
        "tooltip": "",
        "group": "b4ebae93d455bbc5",
        "order": 2,
        "width": 6,
        "height": 1,
        "passthru": true,
        "mode": "number",
        "delay": "100",
        "topic": "lat",
        "sendOnBlur": true,
        "className": "",
        "topicType": "str",
        "x": 230,
        "y": 420,
        "wires": [
            [
                "fa8d16f8a3e226de"
            ]
        ]
    },
    {
        "id": "2aeed1b10c6c1515",
        "type": "ui_button",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "group": "b4ebae93d455bbc5",
        "order": 3,
        "width": 2,
        "height": 1,
        "passthru": false,
        "label": "Set",
        "tooltip": "",
        "color": "",
        "bgcolor": "",
        "className": "",
        "icon": "",
        "payload": "",
        "payloadType": "str",
        "topic": "set",
        "topicType": "str",
        "x": 390,
        "y": 580,
        "wires": [
            [
                "fa8d16f8a3e226de"
            ]
        ]
    },
    {
        "id": "2cb3acd121995f56",
        "type": "worldmap-tracks",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "depth": 20,
        "layer": "single",
        "smooth": false,
        "x": 790,
        "y": 400,
        "wires": [
            [
                "14927396080798d3"
            ]
        ]
    },
    {
        "id": "14927396080798d3",
        "type": "worldmap",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "lat": "48.80",
        "lon": "13.50",
        "zoom": "",
        "layer": "OSMC",
        "cluster": "",
        "maxage": "20",
        "usermenu": "show",
        "layers": "show",
        "panit": "true",
        "panlock": "false",
        "zoomlock": "false",
        "hiderightclick": "false",
        "coords": "deg",
        "showgrid": "false",
        "showruler": "false",
        "allowFileDrop": "false",
        "path": "/worldmap",
        "overlist": "DR,CO,RA,DN,AC,HM",
        "maplist": "OSMG,OSMC,EsriC,EsriS,EsriT,EsriDG,UKOS",
        "mapname": "",
        "mapurl": "",
        "mapopt": "",
        "mapwms": false,
        "x": 1020,
        "y": 460,
        "wires": []
    },
    {
        "id": "3f1eed7c26c68aa2",
        "type": "ui_text_input",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "label": "Initial Lon Position",
        "tooltip": "",
        "group": "b4ebae93d455bbc5",
        "order": 4,
        "width": 6,
        "height": 1,
        "passthru": true,
        "mode": "number",
        "delay": "100",
        "topic": "lon",
        "sendOnBlur": true,
        "className": "",
        "topicType": "str",
        "x": 230,
        "y": 460,
        "wires": [
            [
                "fa8d16f8a3e226de"
            ]
        ]
    },
    {
        "id": "bd958146f73af5c1",
        "type": "ui_button",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "group": "b4ebae93d455bbc5",
        "order": 11,
        "width": 6,
        "height": 1,
        "passthru": false,
        "label": "up",
        "tooltip": "",
        "color": "",
        "bgcolor": "",
        "className": "",
        "icon": "",
        "payload": "",
        "payloadType": "str",
        "topic": "up",
        "topicType": "str",
        "x": 210,
        "y": 340,
        "wires": [
            [
                "fa8d16f8a3e226de"
            ]
        ]
    },
    {
        "id": "83cee2bda843d0d2",
        "type": "ui_button",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "group": "b4ebae93d455bbc5",
        "order": 13,
        "width": 6,
        "height": 1,
        "passthru": false,
        "label": "down",
        "tooltip": "",
        "color": "",
        "bgcolor": "",
        "className": "",
        "icon": "",
        "payload": "",
        "payloadType": "str",
        "topic": "down",
        "topicType": "str",
        "x": 190,
        "y": 520,
        "wires": [
            [
                "fa8d16f8a3e226de"
            ]
        ]
    },
    {
        "id": "03aa2f6ba41795a5",
        "type": "ui_button",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "group": "b4ebae93d455bbc5",
        "order": 15,
        "width": 6,
        "height": 1,
        "passthru": false,
        "label": "left",
        "tooltip": "",
        "color": "",
        "bgcolor": "",
        "className": "",
        "icon": "",
        "payload": "",
        "payloadType": "str",
        "topic": "left",
        "topicType": "str",
        "x": 190,
        "y": 560,
        "wires": [
            [
                "fa8d16f8a3e226de"
            ]
        ]
    },
    {
        "id": "7347a00f5de4aab0",
        "type": "ui_button",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "group": "b4ebae93d455bbc5",
        "order": 17,
        "width": 6,
        "height": 1,
        "passthru": false,
        "label": "right",
        "tooltip": "",
        "color": "",
        "bgcolor": "",
        "className": "",
        "icon": "",
        "payload": "",
        "payloadType": "str",
        "topic": "right",
        "topicType": "str",
        "x": 210,
        "y": 380,
        "wires": [
            [
                "fa8d16f8a3e226de"
            ]
        ]
    },
    {
        "id": "fa8d16f8a3e226de",
        "type": "function",
        "z": "594f4d4bfd9f7699",
        "name": "function 3",
        "func": "var R = 6378.1; // Radius of Earth\nvar dist = 100; // Distance in meters\nvar theta = (dist / R) * 2 * Math.PI; // Angular distance in radians\nvar speed = 0;\n\nvar lat1 = 0.0;\nvar lon1 = 0.0;\n\nvar lat2 = flow.get(\"lat2\") || 0;\nvar lon2 = flow.get(\"lon2\") || 0;\n\nif(msg.topic == \"lat\"){\n lat2 = msg.payload; \n flow.set(\"lat2\", lat2);\n return msg;\n}\n\nif(msg.topic == \"lon\"){\n lon2 = msg.payload ;\n flow.set(\"lon2\", lon2);\n return msg;\n}\n\nvar y = Math.sin(lon2 - lon1) * Math.cos(lat2);\nvar x = Math.cos(lat1)*Math.sin(lat2) - Math.sin(lat1)*Math.cos(lat2)*Math.cos(lon2-lon1);\nvar angle = Math.atan2(y, x);\nvar brng = (angle*180/Math.PI + 360) % 360; // in degrees\n\nif(msg.topic == \"set\"){\n var set_it = {\n name:\"SIMULU\",\n lat: lat2,\n lon: lon2,\n icon: \"plane\",\n iconColor: \"black\",\n layer: \"gps\",\n bearing: brng,\n speed: speed + \"kn\",\n popped: true\n }\n msg.payload = set_it;\n return msg;\n}\n\nvar lat3 = Math.asin(Math.sin(lat1) * Math.cos(theta) +\n Math.cos(lat1) * Math.sin(theta) * Math.cos(brng));\n\nvar lon3 = lon1 + Math.atan2(Math.sin(brng) * Math.sin(theta)* Math.cos(lat1),\n Math.cos(theta) - Math.sin(lat1) * Math.sin(lat3))\n\nvar lat3_deg = lat3 * 180 / Math.PI;\nvar lon3_deg = lon3 * 180 / Math.PI;\n\nlet thing = flow.get(\"location\") || set_it;\nlet heading = thing.heading;\n\nif(msg.topic == \"up\"){\n if(heading = 0){\n heading = 0;\n }\n var up = {\n name:\"SIMULU\",\n bearing:heading,\n layer:\"gps\",\n popped:true\n }\n msg.payload = up;\n return msg;\n}\n\nif(msg.topic==\"right\"){\n if(heading >= 0 || heading < 90){\n heading = 90;\n }\n var right = {\n name:\"SIMULU\",\n bearing:heading,\n layer:\"gps\",\n popped:true\n }\n msg.payload = right;\n return msg;\n}\n\nif(msg.topic == \"down\"){\n if(heading > 90 || heading < 270){\n heading = 180;\n }\n var down = {\n name: \"SIMULU\",\n bearing:heading,\n layer:\"gps\",\n popped:true\n }\n msg.payload = down;\n return msg;\n}\n\nif(msg.topic==\"left\"){\n if(heading > 180 || heading < 360 ){\n heading = 270;\n }\n var left = {\n name:\"SIMULU\",\n bearing:heading,\n layer:\"gps\",\n popped:true\n }\n msg.payload = left;\n return msg;\n}\n\nthing.heading = heading;\nflow.set(\"location\", thing);\nreturn msg;",
        "outputs": 1,
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [],
        "x": 560,
        "y": 420,
        "wires": [
            [
                "9336120dc02d8212",
                "2cb3acd121995f56",
                "14927396080798d3"
            ]
        ]
    },
    {
        "id": "9336120dc02d8212",
        "type": "debug",
        "z": "594f4d4bfd9f7699",
        "name": "debug 4",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "false",
        "statusVal": "",
        "statusType": "auto",
        "x": 880,
        "y": 580,
        "wires": []
    },
    {
        "id": "b4ebae93d455bbc5",
        "type": "ui_group",
        "name": "UAV Flight Control",
        "tab": "37a720198b072daf",
        "order": 1,
        "disp": true,
        "width": "17",
        "collapse": false,
        "className": ""
    },
    {
        "id": "37a720198b072daf",
        "type": "ui_tab",
        "name": "Flight_Control",
        "icon": "dashboard",
        "order": 2,
        "disabled": false,
        "hidden": false
    }
]

```

---

<div class="post-metadata">

**Author:** ![zenofmud](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/zenofmud/32/316_2.png) [@zenofmud](https://discourse.nodered.org/u/zenofmud)\
**Post date:** [20 December 2022 10:44 UTC](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195/8 "2022-12-20T10:44:25Z")

</div>

Well the first thing you have to do is fix your flow because when I use it I get an error  
 ![Screen Shot 2022-12-20 at 5.43.06 AM](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/e/9/e947019c69752e51c689958c2550d9c53647e653.png)

---

<div class="post-metadata">

**Author:** ![Scorpio\_93](https://avatars.discourse-cdn.com/v4/letter/s/5e9695/32.png) [@Scorpio\_93](https://discourse.nodered.org/u/Scorpio_93)\
**Post date:** [21 December 2022 10:02 UTC](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195/9 "2022-12-21T10:02:08Z")

</div>

Hi @zenofmud, I have tried everything to remove/fix the error but I cannot seem to fix it. Any suggestions?

---

<div class="post-metadata">

**Author:** ![zenofmud](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/zenofmud/32/316_2.png) [@zenofmud](https://discourse.nodered.org/u/zenofmud)\
**Post date:** [21 December 2022 10:37 UTC](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195/10 "2022-12-21T10:37:21Z")

</div>

Can you explain why you didn't tell me yesterday that the flow had an error?  
Let me see what changes you made to try and fix the error - show me your current flow.  
Is this a project for school by any chance?

Try adding node-warn() statements to the function node to examine data as it runs. You can read about `node-warn()` in th documentation. [Writing Functions : Node-RED](https://nodered.org/docs/user-guide/writing-functions#logging-events)

---

<div class="post-metadata">

**Author:** ![Scorpio\_93](https://avatars.discourse-cdn.com/v4/letter/s/5e9695/32.png) [@Scorpio\_93](https://discourse.nodered.org/u/Scorpio_93)\
**Post date:** [21 December 2022 10:42 UTC](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195/11 "2022-12-21T10:42:06Z")

</div>

It was working when I sent you the flow but I don't know why it did not worked at your side. Early this morning I also tried the flow and it give me the same error as you stated in the above replies. This is not a project for school by any chance, it is a research project. My current flow is as follows:

```auto
[
    {
        "id": "01732bfeeaa6afce",
        "type": "ui_text_input",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "label": "Initial Lat Position",
        "tooltip": "",
        "group": "b4ebae93d455bbc5",
        "order": 2,
        "width": 6,
        "height": 1,
        "passthru": true,
        "mode": "number",
        "delay": "100",
        "topic": "lat",
        "sendOnBlur": true,
        "className": "",
        "topicType": "str",
        "x": 230,
        "y": 420,
        "wires": [
            [
                "fa8d16f8a3e226de"
            ]
        ]
    },
    {
        "id": "2aeed1b10c6c1515",
        "type": "ui_button",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "group": "b4ebae93d455bbc5",
        "order": 3,
        "width": 2,
        "height": 1,
        "passthru": false,
        "label": "Set",
        "tooltip": "",
        "color": "",
        "bgcolor": "",
        "className": "",
        "icon": "",
        "payload": "",
        "payloadType": "str",
        "topic": "set",
        "topicType": "str",
        "x": 390,
        "y": 580,
        "wires": [
            [
                "fa8d16f8a3e226de"
            ]
        ]
    },
    {
        "id": "2cb3acd121995f56",
        "type": "worldmap-tracks",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "depth": 20,
        "layer": "single",
        "smooth": false,
        "x": 790,
        "y": 400,
        "wires": [
            [
                "14927396080798d3"
            ]
        ]
    },
    {
        "id": "14927396080798d3",
        "type": "worldmap",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "lat": "48.80",
        "lon": "13.50",
        "zoom": "",
        "layer": "OSMC",
        "cluster": "",
        "maxage": "20",
        "usermenu": "show",
        "layers": "show",
        "panit": "true",
        "panlock": "false",
        "zoomlock": "false",
        "hiderightclick": "false",
        "coords": "deg",
        "showgrid": "false",
        "showruler": "false",
        "allowFileDrop": "false",
        "path": "/worldmap",
        "overlist": "DR,CO,RA,DN,AC,HM",
        "maplist": "OSMG,OSMC,EsriC,EsriS,EsriT,EsriDG,UKOS",
        "mapname": "",
        "mapurl": "",
        "mapopt": "",
        "mapwms": false,
        "x": 1020,
        "y": 460,
        "wires": []
    },
    {
        "id": "3f1eed7c26c68aa2",
        "type": "ui_text_input",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "label": "Initial Lon Position",
        "tooltip": "",
        "group": "b4ebae93d455bbc5",
        "order": 4,
        "width": 6,
        "height": 1,
        "passthru": true,
        "mode": "number",
        "delay": "100",
        "topic": "lon",
        "sendOnBlur": true,
        "className": "",
        "topicType": "str",
        "x": 230,
        "y": 460,
        "wires": [
            [
                "fa8d16f8a3e226de"
            ]
        ]
    },
    {
        "id": "bd958146f73af5c1",
        "type": "ui_button",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "group": "b4ebae93d455bbc5",
        "order": 11,
        "width": 6,
        "height": 1,
        "passthru": false,
        "label": "up",
        "tooltip": "",
        "color": "",
        "bgcolor": "",
        "className": "",
        "icon": "",
        "payload": "",
        "payloadType": "str",
        "topic": "up",
        "topicType": "str",
        "x": 210,
        "y": 340,
        "wires": [
            [
                "fa8d16f8a3e226de"
            ]
        ]
    },
    {
        "id": "83cee2bda843d0d2",
        "type": "ui_button",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "group": "b4ebae93d455bbc5",
        "order": 13,
        "width": 6,
        "height": 1,
        "passthru": false,
        "label": "down",
        "tooltip": "",
        "color": "",
        "bgcolor": "",
        "className": "",
        "icon": "",
        "payload": "",
        "payloadType": "str",
        "topic": "down",
        "topicType": "str",
        "x": 190,
        "y": 520,
        "wires": [
            [
                "fa8d16f8a3e226de"
            ]
        ]
    },
    {
        "id": "03aa2f6ba41795a5",
        "type": "ui_button",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "group": "b4ebae93d455bbc5",
        "order": 15,
        "width": 6,
        "height": 1,
        "passthru": false,
        "label": "left",
        "tooltip": "",
        "color": "",
        "bgcolor": "",
        "className": "",
        "icon": "",
        "payload": "",
        "payloadType": "str",
        "topic": "left",
        "topicType": "str",
        "x": 190,
        "y": 560,
        "wires": [
            [
                "fa8d16f8a3e226de"
            ]
        ]
    },
    {
        "id": "7347a00f5de4aab0",
        "type": "ui_button",
        "z": "594f4d4bfd9f7699",
        "name": "",
        "group": "b4ebae93d455bbc5",
        "order": 17,
        "width": 6,
        "height": 1,
        "passthru": false,
        "label": "right",
        "tooltip": "",
        "color": "",
        "bgcolor": "",
        "className": "",
        "icon": "",
        "payload": "",
        "payloadType": "str",
        "topic": "right",
        "topicType": "str",
        "x": 210,
        "y": 380,
        "wires": [
            [
                "fa8d16f8a3e226de"
            ]
        ]
    },
    {
        "id": "fa8d16f8a3e226de",
        "type": "function",
        "z": "594f4d4bfd9f7699",
        "name": "function 3",
        "func": "var R = 6378.1; // Radius of Earth\nvar dist = 100; // Distance in meters\nvar theta = (dist / R) * 2 * Math.PI; // Angular distance in radians\nvar speed = 0;\n\nvar lat1 = 0.0;\nvar lon1 = 0.0;\n\nvar lat2 = flow.get(\"lat2\") || 0;\nvar lon2 = flow.get(\"lon2\") || 0;\n\nif(msg.topic == \"lat\"){\n lat2 = msg.payload; \n flow.set(\"lat2\", lat2);\n return msg;\n}\n\nif(msg.topic == \"lon\"){\n lon2 = msg.payload ;\n flow.set(\"lon2\", lon2);\n return msg;\n}\n\nvar y = Math.sin(lon2 - lon1) * Math.cos(lat2);\nvar x = Math.cos(lat1)*Math.sin(lat2) - Math.sin(lat1)*Math.cos(lat2)*Math.cos(lon2-lon1);\nvar angle = Math.atan2(y, x);\nvar brng = (angle*180/Math.PI + 360) % 360; // in degrees\n\nif(msg.topic == \"set\"){\n var set_it = {\n name:\"SIMULU\",\n lat: lat2,\n lon: lon2,\n icon: \"plane\",\n iconColor: \"black\",\n layer: \"gps\",\n bearing: brng,\n speed: speed + \"kn\",\n popped: true\n }\n msg.payload = set_it;\n return msg;\n}\n\nvar lat3 = Math.asin(Math.sin(lat1) * Math.cos(theta) +\n Math.cos(lat1) * Math.sin(theta) * Math.cos(brng));\n\nvar lon3 = lon1 + Math.atan2(Math.sin(brng) * Math.sin(theta)* Math.cos(lat1),\n Math.cos(theta) - Math.sin(lat1) * Math.sin(lat3))\n\nvar lat3_deg = lat3 * 180 / Math.PI;\nvar lon3_deg = lon3 * 180 / Math.PI;\n\nvar move = flow.get(\"location\") || brng;\nvar heading = move.heading; \nnode.warn(move);\n\nif(msg.topic == \"up\"){\n if(heading = 0){\n heading = 0;\n }\n var up = {\n name:\"SIMULU\",\n bearing:heading,\n layer:\"gps\",\n popped:true\n }\n msg.payload = up;\n return msg;\n}\n\nif(msg.topic==\"right\"){\n if(heading >= 0 || heading < 90){\n heading = 90;\n }\n var right = {\n name:\"SIMULU\",\n bearing:heading,\n layer:\"gps\",\n popped:true\n }\n msg.payload = right;\n return msg;\n}\n\nif(msg.topic == \"down\"){\n if(heading > 90 || heading < 270){\n heading = 180;\n }\n var down = {\n name: \"SIMULU\",\n bearing:heading,\n layer:\"gps\",\n popped:true\n }\n msg.payload = down;\n return msg;\n}\n\nif(msg.topic==\"left\"){\n if(heading > 180 || heading < 360 ){\n heading = 270;\n }\n var left = {\n name:\"SIMULU\",\n bearing:heading,\n layer:\"gps\",\n popped:true\n }\n msg.payload = left;\n return msg;\n}\n\nmove.heading = heading;\nflow.set(\"location\", move);\nreturn msg;",
        "outputs": 1,
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [],
        "x": 560,
        "y": 420,
        "wires": [
            [
                "9336120dc02d8212",
                "2cb3acd121995f56",
                "14927396080798d3"
            ]
        ]
    },
    {
        "id": "9336120dc02d8212",
        "type": "debug",
        "z": "594f4d4bfd9f7699",
        "name": "debug 4",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "false",
        "statusVal": "",
        "statusType": "auto",
        "x": 880,
        "y": 580,
        "wires": []
    },
    {
        "id": "b4ebae93d455bbc5",
        "type": "ui_group",
        "name": "UAV Flight Control",
        "tab": "37a720198b072daf",
        "order": 1,
        "disp": true,
        "width": "17",
        "collapse": false,
        "className": ""
    },
    {
        "id": "37a720198b072daf",
        "type": "ui_tab",
        "name": "Flight_Control",
        "icon": "dashboard",
        "order": 2,
        "disabled": false,
        "hidden": false
    }
]

```

---

<div class="post-metadata">

**Author:** ![Scorpio\_93](https://avatars.discourse-cdn.com/v4/letter/s/5e9695/32.png) [@Scorpio\_93](https://discourse.nodered.org/u/Scorpio_93)\
**Post date:** [21 December 2022 10:45 UTC](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195/12 "2022-12-21T10:45:25Z")

</div>

The error is removed but the other button like down,left and right give me an undefined value.

> [@zenofmud](#):
>
> Try adding node-warn() statements to the function node to examine data as it runs. You can read about `node-warn()` in th documentation. [Writing Functions : Node-RED](https://nodered.org/docs/user-guide/writing-functions#logging-events)

I have added the node.warn() statement in my flow.

---

<div class="post-metadata">

**Author:** ![zenofmud](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/zenofmud/32/316_2.png) [@zenofmud](https://discourse.nodered.org/u/zenofmud)\
**Post date:** [21 December 2022 10:56 UTC](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195/13 "2022-12-21T10:56:42Z")

</div>

When I run your latest flow the debug sidebar shows a message from `debug 4`

```auto
12/21/2022, 5:49:28 AM node: debug 4
down : msg.payload : Object
object
    name: "SIMULU"
    bearing: undefined
    layer: "gps"
    popped: true

```

in the function you set `bearing` to `heading` so where do you define `heading`?

---

<div class="post-metadata">

**Author:** ![Scorpio\_93](https://avatars.discourse-cdn.com/v4/letter/s/5e9695/32.png) [@Scorpio\_93](https://discourse.nodered.org/u/Scorpio_93)\
**Post date:** [21 December 2022 12:20 UTC](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195/14 "2022-12-21T12:20:17Z")

</div>

Previously I defined heading like:

```auto
let heading = move.heading

```

and then:

```auto
bearing:heading

```

but it does not work.

---

<div class="post-metadata">

**Author:** ![Scorpio\_93](https://avatars.discourse-cdn.com/v4/letter/s/5e9695/32.png) [@Scorpio\_93](https://discourse.nodered.org/u/Scorpio_93)\
**Post date:** [21 December 2022 12:23 UTC](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195/15 "2022-12-21T12:23:11Z")

</div>

I know the error is somewhere along these parts of the code:

```auto
if(msg.topic == "set"){
    var set_it = {
        name:"SIMULU",
        lat: lat2,
        lon: lon2,
        icon: "plane",
        iconColor: "black",
        layer: "gps",
        bearing: brng,
        speed: speed + "kn",
        popped: true
    }
    msg.payload = set_it;
    return msg;
}

```

and

```auto
var move = flow.get("location") || set_it;
var bearing = move.bearing; 
node.warn(move);

if(msg.topic == "up"){
    if(bearing = 0){
        bearing = 0;
    }
    var up = {
        name:"SIMULU",
        bearing:bearing,
        layer:"gps",
        popped:true
    }
    msg.payload = up;
    return msg;
}

if(msg.topic=="right"){
    if(bearing >= 0 || bearing < 90){
        bearing = 90;
    }
    var right = {
        name:"SIMULU",
        bearing:bearing,
        layer:"gps",
        popped:true
    }
    msg.payload = right;
    return msg;
}

if(msg.topic == "down"){
    if(bearing > 90 || bearing < 270){
        bearing = 180;
    }
    var down = {
        name: "SIMULU",
        bearing:bearing,
        layer:"gps",
        popped:true
    }
    msg.payload = down;
    return msg;
}

if(msg.topic=="left"){
    if(bearing > 180 || bearing < 360 ){
        bearing = 270;
    }
    var left = {
        name:"SIMULU",
        bearing:bearing,
        layer:"gps",
        popped:true
    }
    msg.payload = left;
    return msg;
}

move.bearing = bearing;
flow.set("location", move);
return msg;

```

---

<div class="post-metadata">

**Author:** ![zenofmud](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/zenofmud/32/316_2.png) [@zenofmud](https://discourse.nodered.org/u/zenofmud)\
**Post date:** [21 December 2022 12:31 UTC](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195/16 "2022-12-21T12:31:51Z")

</div>

I would add a bunch of `node.warn("debug ??")` where `??` is a different number in each one, then run your flow so you can see what is happening in the code.

You could even add one to each if statement like `node.warn("debug ?? - in UP test")`

You can even display variables using something like `node.warn("bearing=" + bearing)`

---

<div class="post-metadata">

**Author:** ![Scorpio\_93](https://avatars.discourse-cdn.com/v4/letter/s/5e9695/32.png) [@Scorpio\_93](https://discourse.nodered.org/u/Scorpio_93)\
**Post date:** [21 December 2022 12:44 UTC](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195/17 "2022-12-21T12:44:04Z")

</div>

I did this:

```auto
let move = flow.get("location") || 0 ;
let bearing = move.bearing; 

if(msg.topic == "up"){
    if(bearing = 0){
        bearing = 0;
    }
    var up = {
        name:"SIMULU",
        bearing:bearing,
        layer:"gps",
        popped:true
    }
    node.warn("bearing=" +bearing);
    msg.payload = up;
    return msg;
}

if(msg.topic=="right"){
    if(bearing >= 0 || bearing < 90){
        bearing = 90;
    }
    var right = {
        name:"SIMULU",
        bearing:bearing,
        layer:"gps",
        popped:true
    }
    node.warn("bearing=" +bearing)
    msg.payload = right;
    return msg;
}

if(msg.topic == "down"){
    if(bearing > 90 || bearing < 270){
        bearing = 180;
    }
    var down = {
        name: "SIMULU",
        bearing:bearing,
        layer:"gps",
        popped:true
    }
    node.warn("bearing=" +bearing)
    msg.payload = down;
    return msg;
}

if(msg.topic=="left"){
    if(bearing > 180 || bearing < 360 ){
        bearing = 270;
    }
    var left = {
        name:"SIMULU",
        bearing:bearing,
        layer:"gps",
        popped:true
    }
    node.warn("bearing=" +bearing)
    msg.payload = left;
    return msg;
}

move.bearing = bearing;
flow.set("location", move);
return msg;

```

![Screenshot from 2022-12-21 13-42-29](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/4/d/4dd7ad38ae135f04d8545d1d55dc7f2b1a1c4c9a.png)

But still I do not understand why it is getting an undefined value? It was perfectly working yesterday without any errors and I even used your previous function code but today it just keeps giving errors.

---

<div class="post-metadata">

**Author:** ![zenofmud](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/zenofmud/32/316_2.png) [@zenofmud](https://discourse.nodered.org/u/zenofmud)\
**Post date:** [21 December 2022 12:47 UTC](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195/18 "2022-12-21T12:47:05Z")

</div>

Please provide the entire function node.

---

<div class="post-metadata">

**Author:** ![Scorpio\_93](https://avatars.discourse-cdn.com/v4/letter/s/5e9695/32.png) [@Scorpio\_93](https://discourse.nodered.org/u/Scorpio_93)\
**Post date:** [21 December 2022 12:47 UTC](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195/19 "2022-12-21T12:47:43Z")

</div>

```auto
var R = 6378.1; // Radius of Earth
var dist = 100; // Distance in meters
var theta = (dist / R) * 2 * Math.PI; // Angular distance in radians
var speed = 0;

var lat1 = 0.0;
var lon1 = 0.0;

var lat2 = flow.get("lat2") || 0;
var lon2 = flow.get("lon2") || 0;

if(msg.topic == "lat"){
    lat2 = msg.payload; 
    flow.set("lat2", lat2);
    return msg;
}

if(msg.topic == "lon"){
    lon2 = msg.payload ;
    flow.set("lon2", lon2);
    return msg;
}

var y = Math.sin(lon2 - lon1) * Math.cos(lat2);
var x = Math.cos(lat1)*Math.sin(lat2) - Math.sin(lat1)*Math.cos(lat2)*Math.cos(lon2-lon1);
var angle = Math.atan2(y, x);
var brng = (angle*180/Math.PI + 360) % 360; // in degrees

if(msg.topic == "set"){
    var set_it = {
        name:"SIMULU",
        lat: lat2,
        lon: lon2,
        icon: "plane",
        iconColor: "black",
        layer: "gps",
        bearing: brng,
        speed: speed + "kn",
        popped: true
    }
    msg.payload = set_it;
    return msg;
}

var lat3 = Math.asin(Math.sin(lat1) * Math.cos(theta) +
            Math.cos(lat1) * Math.sin(theta) * Math.cos(brng));

var lon3 = lon1 + Math.atan2(Math.sin(brng) * Math.sin(theta)* Math.cos(lat1),
            Math.cos(theta) - Math.sin(lat1) * Math.sin(lat3))

var lat3_deg = lat3 * 180 / Math.PI;
var lon3_deg = lon3 * 180 / Math.PI;

let move = flow.get("location") || 0 ;
let bearing = move.bearing; 

if(msg.topic == "up"){
    if(bearing = 0){
        bearing = 0;
    }
    var up = {
        name:"SIMULU",
        bearing:bearing,
        layer:"gps",
        popped:true
    }
    node.warn("bearing=" +bearing);
    msg.payload = up;
    return msg;
}

if(msg.topic=="right"){
    if(bearing >= 0 || bearing < 90){
        bearing = 90;
    }
    var right = {
        name:"SIMULU",
        bearing:bearing,
        layer:"gps",
        popped:true
    }
    node.warn("bearing=" +bearing)
    msg.payload = right;
    return msg;
}

if(msg.topic == "down"){
    if(bearing > 90 || bearing < 270){
        bearing = 180;
    }
    var down = {
        name: "SIMULU",
        bearing:bearing,
        layer:"gps",
        popped:true
    }
    node.warn("bearing=" +bearing)
    msg.payload = down;
    return msg;
}

if(msg.topic=="left"){
    if(bearing > 180 || bearing < 360 ){
        bearing = 270;
    }
    var left = {
        name:"SIMULU",
        bearing:bearing,
        layer:"gps",
        popped:true
    }
    node.warn("bearing=" +bearing)
    msg.payload = left;
    return msg;
}

move.bearing = bearing;
flow.set("location", move);
return msg;

```

---

<div class="post-metadata">

**Author:** ![hotNipi](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/hotnipi/32/383_2.png) [@hotNipi](https://discourse.nodered.org/u/hotNipi)\
**Post date:** [21 December 2022 13:02 UTC](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195/20 "2022-12-21T13:02:50Z")

</div>

Here: if "location is not stored in the flow yet, the move will be 0

```auto
let move = flow.get("location") || 0;

```

Then if move is 0, you cant ask any property from it because 0 has no properties

```auto
let bearing = move.bearing;

```

Here you need to have double ==

```auto
if(bearing = 0){
    bearing = 0;
}

```

Like this

```auto
if(bearing == 0){
    bearing = 0;
}

```

But I cant find any reason to make such statement at all  
if something is already what you want, why to declare it over??

[Next page](https://discourse.nodered.org/t/a-flight-control-system-to-move-icon-in-world-map/72195.md?page=2)