> ## Documentation Index
> Fetch the complete documentation index at: https://docs.isometric.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Project assets [beta]
> The shared framework of sites, activities and materials used to describe the physical structure of a CDR project in Certify
Project assets describe the physical structure of your project: the places where carbon removal happens, the things you do there, and the substances involved. Certify uses a shared framework of asset types defined for each protocol, so the way you upload, link and reference project data is consistent whichever pathway you are certifying.
The project asset model is in the process of being released and is currently supported for:
* **Reforestation projects** using the [Reforestation protocol](https://registry.isometric.com/protocol/reforestation/1.2)
* **Enhanced Weathering projects** using the [Enhanced Weathering in Agriculture protocol](https://registry.isometric.com/protocol/enhanced-weathering-agriculture/1.2)
Other protocols will be migrated to the same model in the near future.
## The asset model
There are three main kinds of project asset.
| Asset | Answers | Examples |
| ------------ | -------------------------------------- | ----------------------------------------------------------------------------- |
| **Site** | *Where activities happen* | A project area, a field, a field plot, a removal area, a measurement location |
| **Activity** | *What happened, and when* | A field plot measurement |
| **Material** | *What physical materials are acted on* | A rock or mineral feedstock, a biomass feedstock |
Sites and activities are available in Certify today. Materials are not yet implemented — this documentation will be extended with additional guides for adding materials when they are.
Every asset, whatever its kind, has:
* A **type**, such as `Field plot` or `Field plot measurement`. Your protocol determines which types your project uses, and Certify only shows the types your project is configured for.
* A **name** and a **reference ID**. The reference ID is yours to choose, is unique within your organisation, and is how you link assets to each other and to data you upload later. See [Supplier Reference ID](/user-guides/certify/supplier-reference-id). The name is a display name for the asset.
* **Metadata**: additional fields defined by your protocol for that type, such as the plot type of an Enhanced Weathering field.
* **Links** to other assets, which define the structure of the project's operations.
### Sites
A site is a place. Each site type has a geographic representation defined by the protocol:
| Geography | What you provide | Upload format |
| --------- | ---------------------------------------------------------------------- | ------------------ |
| **Area** | A polygon or multipolygon boundary | GeoJSON |
| **Point** | A latitude and longitude | CSV |
| **None** | No independent geometry — the site is defined by the sites it contains | Created in Certify |
Sites of the same type are usually organised into a hierarchy: a Reforestation Project Area contains Fields, and each Field contains Field Plots.
Sites can also hold [measurement samples](/user-guides/certify/measurement-samples). For example, soil, biomass, porewater and ion exchange resin samples are taken at Enhanced Weathering measurement locations.
### Site validation
Some site types are also validatable. This means that the site carries its own set of validation requirements that your VVB reviews — see [Add sites](/user-guides/certify/project-assets/add-sites). Site validation allows expansion of projects after the initial project validation, providing supplementary information on new project areas or facilities that have been introduced after the initial [Project Design](/user-guides/certify/project-design) submission.
Validation of sites will typically be conducted by the assigned verifier as part of the first verification of credits derived from the relevant site.
### Activities
An activity is something that happened at a point or period in time. Its type defines:
* A **time** property: either a date, a timestamp, a date range, a timestamp range, or none at all.
* Its **measurements**: the physical quantities recorded for it, each with a quantity kind and unit, and each either required or optional. A reforestation field plot measurement, for instance, records diameter at breast height, and optionally height, latitude, longitude and elevation.
* Its **links**: the site it happens at, any parent or preceding activity, and any materials it references or outputs.
### Links between assets
Links are what turn a list of assets into a structured project. The supported relationships are:
| Relationship | Between | Meaning |
| ---------------------------- | -------------------------------- | --------------------------------------------- |
| `contains` / `part of` | Site → site, activity → activity | A parent-child hierarchy |
| `happens at` / `location of` | Activity → site | Where an activity took place |
| `follows` / `precedes` | Activity → activity | A sequence of activities |
| `references` / `outputs` | Activity → material | The material an activity consumed or produced |
Links are created in one of two ways, defined by the protocol:
* **Explicitly**, by naming the reference ID of the related asset — either in a form in Certify or in a column of an uploaded CSV.
* **By spatial matching**, where Certify links a site to its parent automatically because its geometry falls inside the parent's. Reforestation field plots and Enhanced Weathering measurement locations are linked this way, so you never enter a parent reference ID for them.
## Where to find project assets in Certify
Open the [Certify dashboard](https://registry.isometric.com/account/certify), select your project, and use the left-hand navigation:
* **Sites** lists one tab per site type in your project.
* **Activities** lists one tab per activity type. It only appears if your protocol defines activity types.
The visibility of asset data on the public registry is covered in [Data visibility](/user-guides/certify/data-visibility).
## User guides
Upload the places in your project and the boundaries that define them.
Upload what happened at those places, and the measurements taken.
Every site type, its metadata and its links, per protocol.
Every activity type, its metadata, measurements and links, per protocol.