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

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

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

| 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 |

| 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 |

| 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 |

| 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 |