> For the complete documentation index, see [llms.txt](https://das-metadata.gitbook.io/das-metadata-standard-by-das-rcn/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://das-metadata.gitbook.io/das-metadata-standard-by-das-rcn/term/channel.md).

# Channel metadata

**Channel Metadata**

* Nested under the Channel Group metadata, the individual Channel metadata consists of properties that are unique to each channel, including a unique identifier, coordinates, and for borehole cable, optional strike and dip. Note that the total amount of individual Channel metadata may be equal or less than the number\_of\_channels attribute specified under Acquisition metadata as only a subset of the channels may be included in the data. This is to accommodate cases where channels cannot be located or omitted due to various reasons.
* Required fields *(mark with an asterisk, and indicated in the tables below)*\
  [channel\_id\*](#channel_id) | [channel\_group\_id\*](#channel_group_id) | [distance\_along\_fiber\*](#distance_along_fiber) | [x\_coordinate\*](#x_coordinate) | [y\_coordinate\*](#y_coordinate)
* Optional fields\
  [elevation\_above\_sea\_level](#elevation_above_sea_level) | [depth\_below\_surface](#depth_below_surface) | [strike](#strike) | [dip](#dip)

***

#### channel\_id

| attributeID          | channel\_id  `Required`                                                                                                                                |
| -------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------ |
| **Description**      | Unique identifier of the individual channel, with a maximum of 8 alphanumeric characters with no special characters (e.g., underscores, period, dash). |
| **Required**         | True                                                                                                                                                   |
| **Type**             | String                                                                                                                                                 |
| **Style**            | Alphanumeric                                                                                                                                           |
| **Units or options** | --                                                                                                                                                     |
| **Example**          | 431                                                                                                                                                    |

#### channel\_group\_id

| attributeID          | channel\_group\_id  `Required`          |
| -------------------- | --------------------------------------- |
| **Description**      | Unique identifier of the channel group. |
| **Required**         | True                                    |
| **Type**             | String                                  |
| **Style**            | Alphanumeric                            |
| **Units or options** | --                                      |
| **Example**          | CG001                                   |

#### distance\_along\_fiber

| attributeID          | distance\_along\_fiber  `Required`                                                                                                                                        |
| -------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Description**      | Distance along fiber between the interrogator and channel. Zero meter at the connector to the interrogator; negative distances for fiber section inside the interrogator. |
| **Required**         | True                                                                                                                                                                      |
| **Type**             | Float                                                                                                                                                                     |
| **Style**            | na                                                                                                                                                                        |
| **Units or options** | -                                                                                                                                                                         |
| **Example**          | na                                                                                                                                                                        |

#### x\_coordinate

| attributeID          | x\_coordinate  `Required`                         |
| -------------------- | ------------------------------------------------- |
| **Description**      | x-coordinate (UTM-x or longitude) of the channel. |
| **Required**         | True                                              |
| **Type**             | Float                                             |
| **Style**            | na                                                |
| **Units or options** | -                                                 |
| **Example**          | 328050.69                                         |

#### y\_coordinate

| attributeID          | y\_coordinate  `Required`                         |
| -------------------- | ------------------------------------------------- |
| **Description**      | y-coordinate (UTM-y or latitude)  of the channel. |
| **Required**         | True                                              |
| **Type**             | Float                                             |
| **Style**            | na                                                |
| **Units or options** | -                                                 |
| **Example**          | 4407542.05                                        |

#### elevation\_above\_sea\_level

| attributeID          | elevation\_above\_sea\_level  `Optional` |
| -------------------- | ---------------------------------------- |
| **Description**      | Elevation or height above sea level.     |
| **Required**         | False                                    |
| **Type**             | Float                                    |
| **Style**            | na                                       |
| **Units or options** | -                                        |
| **Example**          | 1231.546                                 |

#### depth\_below\_surface

| attributeID          | depth\_below\_surface  `Optional`         |
| -------------------- | ----------------------------------------- |
| **Description**      | Depth below surface (downwards positive). |
| **Required**         | False                                     |
| **Type**             | Float                                     |
| **Style**            | na                                        |
| **Units or options** | -                                         |
| **Example**          | -                                         |

#### strike

| attributeID          | strike  `Optional`            |
| -------------------- | ----------------------------- |
| **Description**      | Strike of individual channel. |
| **Required**         | False                         |
| **Type**             | Float                         |
| **Style**            | na                            |
| **Units or options** | -                             |
| **Example**          | -                             |

#### dip

| attributeID          | dip  `Optional`            |
| -------------------- | -------------------------- |
| **Description**      | Dip of individual channel. |
| **Required**         | False                      |
| **Type**             | Float                      |
| **Style**            | na                         |
| **Units or options** | -                          |
| **Example**          | -                          |


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