sig.gabrielpantoja.cl — Land GIS

An interactive open-data map of rural land transactions recorded by Chilean Real Estate Registries (Conservadores de Bienes Raíces, CBR) across most of Chile. It combines transaction records with official thematic layers such as protected areas, urban boundaries, administrative boundaries, the national road network, fruit-growing cadastres, and agricultural soils.

The project is designed as an ecoinformatics research tool and as a practical reference for professionals working on court-ordered appraisals and expropriations.

Technology stack

• Next.js 16 (App Router), React 19, and TypeScript
• Tailwind CSS v4
• Leaflet and leaflet.markercluster for imperative clustering of tens of thousands of points
• Neon (@neondatabase/serverless) as the source of truth for CBR transactions, accessed through a SELECT-only web_readonly role
• Vercel deployment at sig.gabrielpantoja.cl

Architecture

The browser never connects directly to PostgreSQL. All database access goes through server-side route handlers that query an explicit allowlist of privacy-safe columns:

Browser → /api/{points,stats,export,facets,hexbins} → Neon (web_readonly, SELECT)
Browser → /api/geocode → Nominatim/OSM (Chile-only address search, cached proxy)
Browser → /api/suelos/{export,identify} → CIREN (fixed, validated proxy)
Browser → /api/vegetacional/{export,identify} → CONAF (fixed, validated proxy)
Browser → /api/propiedades-rurales/{export,identify,feature,search} → SII/CIREN (fixed, validated proxy)
Browser → POST /api/analisis/predio → Neon PostGIS (capas.* + CBR points) + Copernicus DEM (parcel report)

The parcel report («Ficha del predio») takes a polygon drawn on the map, pasted as UTM vertices, loaded from a KML or found by CIREN ROL, and returns its comuna, urban limit and protected areas (official geometry loaded unsimplified into the capas schema by npm run data:load:postgis), slope by SAG class from Copernicus GLO-30 and nearby CBR comparables per land use. The polygon is not stored.

Exports (/api/export?format=csv|geojson) are Excel-friendly CSV or GeoJSON for QGIS. Filters are parameterised SQL (src/lib/filters.ts); full design notes live in docs/.

Data and privacy

Each point exposes lat, lng, monto, anio, comuna, predio, superficie, rol, destino, fechaEscritura, fechaInscripcion, fojas, numero and conservador.

• rol is intentionally public: it is the SII property identifier, not personal data under Chilean Law No. 19,628.
• Never exposed: comprador, vendedor, rut, user_id, observaciones — excluded at the query/handler level.
• Credentials stay server-side (NEON_DATABASE_URL); the client never connects to Neon.

Data sources and licences

Layer	Source	Licence / terms	Build or runtime path
CBR transactions	Project-maintained compilation of CBR registrations	Open data, anonymised in accordance with Chilean Law No. 19,628	Neon Postgres through a read-only role
Value heat map ($/m²)	Derived from the CBR transactions: PostGIS hexagonal medians, interpolated client-side	Same as CBR transactions; market signal, not an appraisal	Derived layer, no ETL: /api/hexbins + src/lib/heat-surface.ts
Protected areas (RNAP)	Ministry of the Environment — National Registry of Protected Areas, Public Baselines portal	CC0 1.0 (public domain)	npm run data:build:protected (mapshaper ETL)
Urban boundaries (PRC)	MINVU — municipal regulatory plans	Confirm terms with MINVU; referential use	npm run data:build:urban
Municipal boundaries (DPA)	SUBDERE — 2023 Political-Administrative Division (geoportal.cl)	Chilean government open data	npm run data:build:comunas
National road network	MOP — Directorate of Roads (mapasvialidad.mop.gob.cl)	Confirm terms with MOP; referential use	npm run data:build:red-vial
Electrical transmission lines	Ministry of Energy — IDE Energía; CEN geometry	Institutional public coverage; no standard licence declared; attribution required	npm run data:build:lineas-transmision
Drainage network (rivers and streams)	DGA — Banco Nacional de Aguas (ArcGIS FeatureServer)	Chilean government open data; DGA attribution, see src/lib/red-drenaje.ts	npm run data:build:red-drenaje
Fruit-growing cadastre	CIREN-ODEPA through IDE Minagri	CIREN-ODEPA attribution; see src/lib/catastro-fruticola.ts	npm run data:build:catastro-fruticola
Vegetation resources	CONAF through SIT CONAF and IDE Minagri

Static layers ship under public/data/ (~45 MB) with a *.meta.json provenance file and are rebuilt with npm run data:build:<layer>. Exact attribution strings live in src/lib/*.ts.

Reading the layers correctly

• RNAP has 12 legal designations, each with its own legal framework — never a single category.
• Bioclimate is a 1970–2000 climatology interpolated from weather stations, not a site measurement.
• Transmission lines are referential centre-lines, not safety corridors, easements or property encumbrances.

Local development

cp .env.example .env.local   # set NEON_DATABASE_URL (web_readonly role)
npm install
npm run dev                  # http://localhost:3000
npm run lint && npm run typecheck   # before submitting a change

NEON_DATABASE_URL is server-side only: never prefix it with NEXT_PUBLIC_ and never commit .env.local.

Roadmap and contributing

Planned layers and UX work are prioritised in docs/roadmap.md. Contributions are welcome — read CONTRIBUTING.md and CODE_OF_CONDUCT.md first. Report security issues via SECURITY.md, not a public issue.

Licence

• Source code: MIT © 2026 Gabriel Pantoja
• Data layers: each keeps its own licence (table above). WorldClim 2.1 is CC BY 4.0 and must be cited as Fick & Hijmans (2017), Int. J. Climatol. 37(12): 4302–4315.
• Basemaps: © OpenStreetMap contributors, Esri World Imagery or OpenTopoMap, per src/lib/basemap.ts.