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.
