# `Diffo.Provider.BaseGeographicSite`
[🔗](https://github.com/diffo-dev/diffo/blob/v0.9.0/lib/diffo/provider/components/base_geographic_site.ex#L5)

Ash Resource Fragment for TMF674 GeographicSite — named-location-style Place
(exchange, office, branch, data centre, etc.).

Compose with `BasePlace` on a concrete leaf to get the TMF GeographicSite
attribute set, an optional projected reference to an associated
`GeographicAddress`, TMF camelCase jason wire shape, and a site-shaped
outstanding signature.

`Diffo.Provider.GeographicSite` uses this fragment directly as the
out-of-the-box TMF GeographicSite resource. Domain extenders compose the same
two fragments on their own leaf for richer domain identity:

    defmodule MyApp.SydneyExchange do
      use Ash.Resource,
        fragments: [Diffo.Provider.BasePlace, Diffo.Provider.BaseGeographicSite],
        domain: MyApp.Domain

      attributes do
        attribute :rack_count, :integer, public?: true
      end

      actions do
        create :build do
          accept [:id, :href, :name, :site_type, :site_code, :address_id, :rack_count]
          change set_attribute(:type, :GeographicSite)
        end
      end
    end

## Attributes

All site attributes are permissive — tighten on your derived leaf if needed.

- `site_type` — atom, free-form (e.g. `:office`, `:exchange`, `:branch`,
  `:datacentre`). Convention only; not constrained.
- `site_code` — string, an opaque human-readable identifier scoped to the
  site (e.g. `"SYD-01"`).
- `address_id` — string FK to an associated address Place. Resolved by the
  `:address` calculation.

## Address association — `:address` (projected)

A `calculate :address` calculation uses `Diffo.Provider.Calculations.ProjectedRef`
to resolve `address_id` to the concrete `GeographicAddress` subtype (or a
consumer-domain Address leaf) via `AshNeo4j.worlds/1`. Open-world by
construction — works whether the target is `Provider.GeographicAddress` or
`MyApp.PostalAddress`.

Result is `nil` when `address_id` is unset; a concrete address struct when
resolved; `%Diffo.Unknown{}` when the id is set but can't be projected.

## Wire shape (TMF674)

`jason.pick` selects base + site fields and renames to TMF camelCase
(`siteType`, `siteCode`). Inherits BasePlace's `encode_geo_json/2` customize
— a no-op for typical Site records (no geometry).

# `extensions`

# `opts`

# `persisted`

# `spark_dsl_config`

# `validate_sections`

---

*Consult [api-reference.md](api-reference.md) for complete listing*