> ## 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.
# Sites reference
> Every site type available in Certify per protocol, with its geography, metadata, links and upload format
This page lists every site type Certify supports, grouped by protocol. Your project only has the site types belonging to its protocol and protocol version. For how to add sites, see [Add sites](/user-guides/certify/project-assets/add-sites).
## Overview
Each site type below is described by the following attributes.
| Attribute | Meaning |
| --------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| **Key** | The identifier used in the API and in exports. |
| **Geography** | How the site is located, which determines the upload format. **Area** takes a Polygon or MultiPolygon in GeoJSON, **Point** takes a latitude and longitude in CSV, and **None** means the site has no geometry of its own and is defined by the sites it contains. |
| **Overlapping geometry** | Whether two sites of this type are allowed to overlap one another. |
| **Validation requirements** | Whether the site carries its own set of validation requirements that your VVB reviews. Validatable sites have a **Requirements** tab and can have [issues](/user-guides/certify/log-of-issues) raised against them. |
| **Upload** | The CSV columns, or GeoJSON feature properties, expected for the type. Always download the template from Certify rather than copying these by hand, since they follow your protocol version. |
| **Metadata** | The extra fields defined for the type. Fields with allowed values must use one of those values exactly. |
| **Links** | The other assets this type connects to. **Explicit** links are ones you provide, by naming the related asset's reference ID or by uploading children as part of the parent's **Add** flow. **Spatial matching** links are made by Certify from the geometry. |
| **Measurement samples** | The [measurement sample](/user-guides/certify/measurement-samples) types that can be recorded at the site. |
Every site type also takes a `name` and a `reference_id`, both required and not repeated in the tables below. See [Supplier Reference ID](/user-guides/certify/supplier-reference-id).
## Reforestation
Site types for projects using the [Reforestation protocol](https://registry.isometric.com/protocol/reforestation/1.2), version 1.2.
### Project Area
A project area includes one or more fields managed in the same way. Each project area must cover at least one hectare and contain field plots where tree measurements are taken to quantify or validate the above-ground biomass (AGB) at each reporting period. CDR quantification is carried out per project area.
| | |
| ----------------------- | ------------------------------------------------------------------------- |
| Key | `reforestation_project_area` |
| Geography | None |
| Validation requirements | Yes — `project_area_validation` |
| Upload | Name and reference ID entered in Certify, with the GeoJSON for its fields |
| Metadata | None |
| Relationship | Related type | Cardinality | Link creation |
| ------------ | ------------ | ----------- | ------------- |
| contains | Field | One to many | Explicit |
A project area groups fields that are managed in the same way. Where fields are planted at different times or with different species mixes, upload each such set of fields as its own GeoJSON feature so Certify creates a separate Field for it.
### Field
A land area within a project area which is planted at the same time and with the same species mix.
| | |
| ----------------------- | --------------------------------------------- |
| Key | `reforestation_field` |
| Geography | Area |
| Overlapping geometry | Not allowed |
| Validation requirements | No |
| Upload | GeoJSON, from the project area's **Add** flow |
| GeoJSON properties | `name`, `reference_id` |
| Metadata | None |
| Relationship | Related type | Cardinality | Link creation |
| ------------ | ------------ | ----------- | ---------------- |
| part of | Project Area | Many to one | Explicit |
| contains | Field Plot | One to many | Spatial matching |
### Field Plot
Field plots are areas within fields where tree parameters are measured to quantify above-ground biomass (AGB). Each field plot must have a unique reference ID, so that tree measurements can be linked to the right plot.
| | |
| ----------------------- | -------------------------- |
| Key | `reforestation_field_plot` |
| Geography | Area |
| Overlapping geometry | Allowed |
| Validation requirements | No |
| Upload | GeoJSON |
| GeoJSON properties | `name`, `reference_id` |
| Metadata | None |
| Relationship | Related type | Cardinality | Link creation |
| ------------ | --------------------------------------------------------------------------------------------------------- | ----------- | ------------------------- |
| part of | Field | Many to one | Spatial matching |
| location of | [Field plot measurement](/user-guides/certify/project-assets/activities-reference#field-plot-measurement) | One to one | Explicit, on the activity |
## Enhanced Weathering in Agriculture
Site types for projects using the [Enhanced Weathering in Agriculture protocol](https://registry.isometric.com/protocol/enhanced-weathering-agriculture/1.2), version 1.2.
### Removal area
A removal area is a set of plots within the project area used to quantify weathering after spreading rock and mineral feedstock. It includes treatment and (if using the 3-plot model) deployment plots where feedstock was spread, as well as control plots without feedstock for comparison.
| | |
| ----------------------- | ------------------------------------------------------------------------- |
| Key | `removal_area` |
| Geography | None |
| Validation requirements | Yes — `removal_area_validation` |
| Upload | Name and reference ID entered in Certify, with the GeoJSON for its fields |
| Metadata | None |
| Relationship | Related type | Cardinality | Link creation |
| ------------ | ------------ | ------------ | ------------- |
| contains | Field | Many to many | Explicit |
### Field
An agricultural field where feedstock is applied.
| | |
| ----------------------- | --------------------------------------------- |
| Key | `enhanced_weathering_field` |
| Geography | Area |
| Overlapping geometry | Not allowed |
| Validation requirements | No |
| Upload | GeoJSON, from the removal area's **Add** flow |
| GeoJSON properties | `name`, `reference_id`, `plot_type` |
| Metadata | Key | Required | Allowed values |
| --------- | ----------- | -------- | ------------------------------------------------ |
| Plot type | `plot_type` | Yes | `control`, `treatment`, `deployment`, `research` |
| Relationship | Related type | Cardinality | Link creation |
| ------------ | -------------------- | ------------ | ---------------- |
| part of | Removal area | Many to many | Explicit |
| contains | Measurement location | One to many | Spatial matching |
### Measurement location
A measurement location is a recorded latitude and longitude where a sample was collected. For example, this could be where a soil core was extracted or an ion exchange resin device was installed.
| | |
| ----------------------- | ------------------------------------------------------------------------------------------------------------------------ |
| Key | `measurement_location` |
| Geography | Point |
| Validation requirements | No |
| Upload | CSV |
| CSV columns | `name`, `reference_id`, `latitude`, `longitude` |
| Metadata | None |
| Measurement samples | Soil (`ew_soil`), Biomass (`ew_field_biomass`), Porewater (`ew_porewater`), Ion exchange resin (`ew_ion_exchange_resin`) |
| Relationship | Related type | Cardinality | Link creation |
| ------------ | ------------ | ----------- | ---------------- |
| part of | Field | Many to one | Spatial matching |
Sample data can only be uploaded once its measurement locations exist, because each sample must be linked to one.