@tak-ps/node-cot NPM

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

About

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

Installation

NPM

To install node-cot with npm run

npm install @tak-ps/node-cot

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.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

Usage Examples

Basic Usage

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

const message = '<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"/><detail><takv os="29" version="4.0.0.0 (deadbeef).1234567890-CIV" device="Some Android Device" platform="ATAK-CIV"/><contact xmppUsername="xmpp@host.com" endpoint="*:-1:stcp" callsign="JENNY"/><uid Droid="JENNY"/><precisionlocation altsrc="GPS" geopointsrc="GPS"/><__group role="Team Member" name="Cyan"/><status battery="78"/><track course="80.24833892285461" speed="0.0"/></detail></event>'

const cot = new CoT(message);

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

cot.raw; // JSON XML Representation

Known Special CoT Types

The following list is a very incomplete list of "special" CoT types and behaviors

CoT Type	Notes
`u-d-f`	LineString or Polygon
`u-d-r`	4 Cornered Rectangle
`b-a-o-tbl`	911 Alert
`b-a-o-can`	Cancel
`b-a-g`	GeoFenceBreach
`b-a-o-pan`	RingTheBell
`b-a-o-opn`	TroopsInContact
`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
`t-x-m-c-l`	Mission Change Notification
`t-x-m-i`	Mission Invite Notification