@tak-ps/node-cot

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