Every kind of boundary
keeps its own identity.

The spine, the families, and crosswalks

The administrative spine is a country's main nested geography, from the country down to its smallest maintained areas. It is the main join path, and every loc_id on it reads like a path. Geometry families hold every other kind of boundary. They may overlap the spine and each other. Crosswalks connect them, recording containment, correspondence, membership, or measured overlap.

Together these form the DaedalMap reference graph: the loc_id identities plus the hierarchy, aliases, history, and crosswalks that connect them. External reference bridges link that graph to outside id systems, such as GERS and Overture, while both keep their own ids and release schedules.

Each country starts with its administrative spine. After that there is no fixed order: sources, local needs, and ongoing research decide which families come next.

One point, many geographies

A single spot in a city sits inside many boundaries at once, and each one is drawn by a different authority for a different purpose. Here is the CN Tower in Toronto, checked against every family published for Canada.

None of these boundaries has to line up with the others. The postal area, the census tract, and the health region exist for mail delivery, the census, and health services. A family keeps its own meaning, source, ids, geometry, and release, so a dataset keyed by any one of them stays correct on its own terms.

Family definitions

Every country uses the same family definitions, so a postal area or a health region means the same thing wherever it appears. A definition here does not mean every country publishes that family: the Geometry Library shows what each country has.

The same name, different geography

"Sydney" means three different shapes, depending on who is asking. Each is a real boundary with its own id, and none of them stands in for the others.

The rule behind this: classify what a source means, not what its layer is called or whether its shape happens to fit inside another polygon. A few distinctions come up often.

Families change on their own clock

Country History follows the geography shown in publisher source editions. An edition year identifies the map or data snapshot we collected. It is not the legal effective date of every boundary in that snapshot. We use a specific event date only when a publisher record supports it, and keep the source snapshot date separate from that event. Different families can have different edition schedules; the latest map of one family does not update every other family to the same year.

Every family is released on its source's schedule. Canada redraws its federal electoral districts after each ten-year census. The CN Tower falls in a district from each of the last four representation orders, and each is kept as its own record.

Release and effective dates are part of what a record means. A historical correspondence between two releases is evidence that the areas overlap in time; it does not by itself claim that one district succeeded the other.

Reading a family id

A family id is the owning country, an area-depth prefix, a family token, and the source's own code.

The prefix records how big the area is, not who governs it. DaedalMap measures the full shape in an equal-area projection and compares it with a scale profile built from the country's spine: the median area at each spine level, with thresholds at the geometric midpoints between those medians. A small area gets a long prefix and a large one a short prefix. The spine area it overlaps most at that depth supplies the prefix, and every overlap is kept as crosswalk evidence. Population and importance never change the depth.

Because the prefix is area precision rather than parentage, read family ids with the geometry tools instead of dropping segments the way you would on the spine. Every id is rooted in one owning country, and DaedalMap never guesses ownership from a name or a center point. Public aliases such as USA-POSTAL-ZCTA-22030-071385E6 resolve to the same record as the canonical id. Global source identifiers such as IHO1953-240001002 (the Mediterranean Sea) stay source aliases until a canonical identity has reviewed country ownership.

How relationships are described

A crosswalk always says what kind of relationship it records.

Land, water, and marine layers

A coordinate can be checked against the physical land/water edge, named water bodies such as oceans, seas, and lakes, the administrative spine on land, and marine jurisdictions such as EEZs. Each answers its own question, and a marine jurisdiction can overlap a sea without redefining it. For hazards this matters: a tsunami coordinate may be an offshore origin, a coastal runup, or an inland observation, and DaedalMap keeps the source coordinate unchanged instead of snapping it to the nearest country.

Cities, addresses, and networks

A city can be on the spine, in place_or_municipality, in urban_or_metro_area, or a name record in named_feature, as Sydney shows. A street address is an input, not a family: an address lookup supplies a coordinate, and the point resolver finds the spine and overlapping families from there. Roads, rail, river flow, and power lines are network programs, and parcels belong to a land-tenure program; both can use loc_id without being treated as polygon families.

Get the geometry

Geometry packages come in three tiers: Lite for identities and crosswalks, Display for simplified map shapes, and Detail for the full maintained geometry.