Node-CoT

Typescript/Javascript Cursor-On-Target Library

Lightweight Typescript library for parsing and manipulating TAK related messages, primarily Cursor-on-Target (COT)

About

node-cot converts between TAK message protocols (XML & Protobuf) and a Javascript object/JSON format. It also can bidirectionally convert CoT messages into GeoJSON

It also support creating and parsing the following TAK Data Types

• Data Packages (CoTs, Attachments, etc)
• Basemap XML Documents

Installation

NPM

To install node-cot with npm run

npm install @tak-ps/node-cot

Usage Examples

Cursor-On-Target

import CoT from '@tak-ps/node-cot';

const cot = new CoT(`
    <event version="2.0" uid="ANDROID-deadbeef" type="a-f-G-U-C" how="m-g" time="2021-02-27T20:32:24.771Z" start="2021-02-27T20:32:24.771Z" stale="2021-02-27T20:38:39.771Z">
        <point lat="1.234567" lon="-3.141592" hae="-25.7" ce="9.9" le="9999999.0"/>
    </event>
`);


// Export Formats
cot.to_geojson();   // Output GeoJSON Representation
cot.to_xml();       // Output String XML Representation

cot.raw; // JSON XML Representation

Debugging

If the Environment Variable DEBUG_COTS is truthy ie:

export DEBUG_COTS=1

Then the raw JSONified XML will be printed on each constructor invocation.

CoT Spec

The CoT Spec is very informally developed by rough internal concensus of large TAK Clients within the TPC (TAK Product Center). The following is a current understanding of the spec primarily developed through reverse engineering TAK clients

<event version uid type how time start stale/>

Event Attributes

Name	Description	Example
version	CoT Version, currently 2.0	version="2.0"
uid	Globally unique name for this information on this event	uid="any-unique-string-123"
type	Hierarchically organized hint about event type	`type="a-f-G-E"'
how	Gives a hint about how the coordinates were generated	how=""
time	The time at which the event was generated	time="2023-07-18T15:25:09.00Z"
start	The time at which the event starts or is relevant	start="2023-07-18T15:25:09.00Z"
stale	The time at which the event ends or is not relevant	stale="2023-07-18T15:25:09.00Z"

CoT GeoJSON Spec

One of the primary use-cases of this library is to make serialization and deserialiation from more commmon geospatial formats a breeze. This section will walk through CoT options that are exposed via the from_geojson() function.

Supported Geometries

• All Input Geometries must be a GeoJSON Feature type
• Point, Polygon, and LineString are all supported
• Multi Geometries are not supported and must be cast to their non-multi type before being passed to the library
• Centroids are calulated using a PointOnSurface algorithm

Supported Properties

The following are the most important/relevant properties

Property	Description
.id	Used as the CoT uid - If omitted a UUID is generated
.properties.type	CoT type - note this will be overridden if geometry is not a Point
.properties.how	CoT how
.properties.time	Time at which CoT was created
.properties.start	Time at which CoT is relevant
.properties.stale	Time at which CoT expires
.properties.callsign	Displayed callsign (basically the name of the feature)
.properties.speed	Speed in m/s of the object
.properties.course	Course in degrees from north of the object
.properties.remarks	Human readable remarks field

Styles can also be applied to features using the following

Property	Description
.properties.marker-color	Point
.properties.marker-opacity	Point
.properties.stroke	Polygon/LineString
.properties.stroke-opacity	Polygon/LineString: Int from 0-256
.properties.stroke-width	Polygon/LineString
.properties.stroke-style	Polygon/LineString
.properties.stroke-style	Polygon/LineString
.properties.fill	Polygon
.properties.fill-opacity	Polygon: Int from 0-256

These are less common properties that can be used:

Property	Description
.properties.icon	String: Custom Icon Path (string)
.properties.archived	Boolean: TAK Clients will ignore the stale value and retain the feature
.properties.dest	Marti API Instructions for sending CoTs to a specific location
.properties.fileshare	Push Data Packages via CoT

Known Special CoT Types

Geometry

CoT Type	Notes
u-d-f	LineString or Polygon
u-d-r	4 Cornered Rectangle
u-d-p	Point

Internal

CoT Type	Notes
t-x-c-t	TAK Server Ping Request
t-x-c-t-r	TAK Server Pong Response

Notification/Alerts

CoT Type	Notes
b-a	Alert
b-a-o-tbl	911 Alert
b-a-o-can	Cancel Alert
b-a-g	GeoFence Breach
b-a-o-pan	RingTheBell
b-a-o-opn	TroopsInContact
b-r-f-h-c	Casevac

Chat

CoT Type	Notes
b-t-f	Chat
b-t-f-d	Chat delivery receipt
b-t-f-r	Chat read receipt
b-t-f-p	Chat pending receipt
b-t-f-s	Chat delivery failure

Mission Sync

CoT Type	Notes
t-x-m	Mission
t-x-m-n	Mission Created
t-x-m-d	Mission Deleted
t-x-m-i	Mission Invite Notification
t-x-m-c	Mission Change
t-x-m-c-h	Mission Change: Layer
t-x-m-c-l	Mission Change: Log
t-x-m-c-e	Mission Change: External
t-x-m-c-m	Mission Change: Metadata
t-x-m-c-k	Mission Change: Keywords

Special

CoT Type	Notes
b-i-v	Bits/Imagery/Video
b-i-r-r	Remote Resource
b-f-t-r	File Transfer Request
b-i-x-i	QuickPic
b-m-r	Route
b-m-p-c	Route Control Point
b-m-p-w	Route Way Point