# Construct Header

![](https://894783789-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LPHXQ1I3gb93zpLrLZf%2Fuploads%2Fgit-blob-96ecaf7f91de3bb594045d33e599051fc6e3e1e0%2FConstruct_Header.png?alt=media)

![](https://894783789-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LPHXQ1I3gb93zpLrLZf%2Fuploads%2Fgit-blob-7f56aae2a403bf03574933456c3c6a391341d95d%2FConstruct_Header.png?alt=media) - [\[source code\]](https://github.com/ladybug-tools/ladybug-grasshopper/blob/master/ladybug_grasshopper/src/LB%20Construct%20Header.py)

Construct a Ladybug Header to be used to create a ladybug DataCollection.

### Inputs

* **data\_type \[Required]**

Text representing the type of data (e.g. Temperature). A full list of acceptable inputs can be seen by checking the all\_u output of the "LB Unit Converter" component. This input can also be a custom DataType object that has been created with the "LB Construct Data Type" component.

* **unit**

Units of the data\_type (e.g. C). Default is to use the base unit of the connected\_data\_type.

* **a\_period**

Script variable constrData

* **metadata**

Optional metadata to be associated with the Header. The input should be a list of text strings with a property name and value for the property separated by a colon. For example: . source: TMY . city: New York . country: USA

### Outputs

* **header**

A Ladybug Header object.