# What are the units of measurement in \_track.qo

**URL:** https://discuss.blues.com/t/what-are-the-units-of-measurement-in-track-qo/98
**Category:** Notehub.io
**Created:** [January 14, 2021, 7:43pm UTC](https://discuss.blues.com/t/what-are-the-units-of-measurement-in-track-qo/98 "2021-01-14T19:43:27Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![gwolff](https://avatars.discourse-cdn.com/v4/letter/g/a88e57/32.png) [@gwolff](https://discuss.blues.com/u/gwolff)
#### Post date: [January 14, 2021, 7:43pm UTC](https://discuss.blues.com/t/what-are-the-units-of-measurement-in-track-qo/98/1 "2021-01-14T19:43:27Z")

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Describing the Units for the JSON fields that have measurements collected by `note.add` request saved to `_track.qo`

* * *

_About Time Stamps_

All timestamps are Unix Epoc UTC

* * *

```json

{
    "device": "dev:xxxxxxxxxxxxxxx",
    "product": "xxxxxxxxxxx",
    "received": 1609850322.396112, // [seconds] timestamp when data was received by Notehub
    "routed": 1609850326, // [seconds] timestamp when data was routed to external URL
    "req": "note.add"
    "when": 1609850291, // [seconds] timestamp when note was added to _track.qo
    "file": "_track.qo",
    "updates": 1,
    "body": {
        "bearing": 355.4197017075076, // [degrees] compass bearing from true north
        "distance": 97.61843922720755, // [meters] distance travelled
        "jcount": 4, // [count] enumeration of notes in the current journey
        "journey": 1609850177, // [seconds] timestamp when journey began
        "motion": 3, // [count] number of motion events detected
        "seconds": 30, // [seconds] period between this GPS location measurement and previous
        "temperature": 14.125, // [Celsius] temperature of Notecard
        "time": 1609850291, // [seconds] timestamp when location acquired
        "velocity": 0.0025266186775858668, // [meters/second]
        "voltage": 5.215444224184539 // [Volts] supply voltage to Notecard modem
    },

    "where_lat": 42.3651325, // [degrees] GPS acquired latitude
    "where_lon": -71.17483203125, // [degrees] GPS acquired longitude
    "tower_when": 1609850321, // [seconds] timestamp when tower connection was established
    "tower_lat": 42.357962500000006, // [degrees] Approximate tower latitude
    "tower_lon": -71.179046875, // [degrees] Approximate tower longitude
}

```

## What is Journey and JCount?

A journey is a contiguous sequence of GPS location captures that are determined to be part of the same journey or trip between locations.

In the JSON data, `journey` field is the timestamp the sequence started. This uniquely identifies the journey sequence for a specific Notecard.

The `jcount` field is the enumeration of GPS location updates stored in `_track.qo` for a particular journey. The `jcount` field starts at 1.

These fields are only available if the tracking mode is enabled, and the GPS tracking period is less than 300 seconds (5 minutes).

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### Author: ![Karl\_iWell](https://avatars.discourse-cdn.com/v4/letter/k/7feea3/32.png) [@Karl\_iWell](https://discuss.blues.com/u/Karl_iWell)
#### Post date: [July 9, 2024, 7:08pm UTC](https://discuss.blues.com/t/what-are-the-units-of-measurement-in-track-qo/98/2 "2024-07-09T19:08:07Z")

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How is velocity calculated?

Is it the instantaneous velocity of the time the location is captured, or is it the average velocity since the last GPS location?

Thanks,  
Karl

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### Author: ![RobLauer](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.blues.com/roblauer/32/1567_2.png) [@RobLauer](https://discuss.blues.com/u/RobLauer)
#### Post date: [July 22, 2024, 2:25pm UTC](https://discuss.blues.com/t/what-are-the-units-of-measurement-in-track-qo/98/3 "2024-07-22T14:25:50Z")

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Hi @Karl_iWell,

When GPS is enabled it supplies data to the Notecard at regular intervals, which updates the “current location” values returned by `card.location`. When the GPS is in `continuous` mode the location is being updated super frequently once it is locked onto satellites.

Velocity is computed and placed into `_track.qo` Notefiles when in a tracking mode. Every time motion starts we begin a “journey” and start logging Notes that contain velocity and bearing, and when motion stops we shut down the gps.

Hope that helps!  
Rob