LADM & Land System Cheat Sheet

The whole course on one page: LADM core, the temporal pattern, mutation effects, service standards, CRS rules, and the systematic pipeline.

LADM core — the sentence

Test of a good model: geometry can change without touching rights, and rights can change without touching geometry. If either forces the other, the seam is misplaced.

Temporal pattern

begin_lifespan / end_lifespan
   system time — when believed
begin_real_world / end_real_world
   real-world time — when true

current  = end_lifespan IS NULL
historic = as-of date between

Never UPDATE in place
Never DELETE
Close old version, insert new
A March deed lodged in September is true from March, known from September

Mutation effects

Event	Spatial	Legal
Subdivision	✓	✓
Merger	✓	✓
Boundary correction	✓	—
Sale / transfer	—	✓
Mortgage created	—	✓
Name correction	—	✓

Retired parcel identifiers are never reissued. Closed parcels record their successors.

Fit-for-purpose

Three frameworks: spatial · legal · institutional
Accuracy is relative to purpose, not instruments
General boundary: the physical feature rules
Fixed boundary: the coordinates rule
Imagery ≈ 50 cm pixels; 1:2,000 rural, 1:500 dense urban
Legal framework: a continuum of tenure, not just freehold
Everything captured must be upgradeable later

Registration modes

	Systematic	Sporadic
Trigger	State declares area	Owner or deal
Scope	All parcels	One parcel
Unit of work	Block / cohort	Application
Display	Mandatory	None
Disputes	Tribunal, collective	Case by case
Goal	Coverage	Service

Systematic pipeline

Services & coordinates

OGC standards

Legacy	Current	Serves
WMS	OGC API — Maps	Rendered images
WFS	OGC API — Features	Vector features
WMTS	OGC API — Tiles	Tile pyramids

"Viewable" → WMS · "Queryable/downloadable" → WFS
Writes need WFS-T or a write-capable feature API
Proposal answer: OGC API primary, WMS/WFS retained

CRS rules

EPSG:4326 — WGS 84 degrees; interchange only
EPSG:3857 — Web Mercator; display only
National projected grid — storage, area, distance
Never measure in degrees
Never store cadastral data in Web Mercator
Axis order: 4326 is lat,lon — GeoJSON is lon,lat
Wrong CRS fails silently. Test control points.

Stack decision

Sustainability is a capacity plan, not a licence choice. Answer who operates this in year four, on whose budget first; the stack follows.

	ArcGIS Enterprise	Open (PostGIS/GeoServer/QGIS)
Real gap	Server-hosted geoprocessing, distributed analysis	No processing service tier
Cost	Recurring licences outlive grants	No licence cost
Risk	Lock-in; dark system if renewal lapses	Scarce maintenance skills in-country
Prior art	—	FAO SOLA: LADM-based, already built