Geospatial

'Everything is related to everything else, but near things are more related than distant things': Waldo Tobler's 1970 principle, which underlies spatial interpolation and much of geographic reasoning.

The risk that debris in low Earth orbit reaches a density where collisions create more debris faster than it decays, making orbits unusable: a tragedy of the commons in space.

1970 paper by Waldo Tobler in Economic Geography, a computer animation of Detroit's growth, in which he states the first law of geography.

1978 paper by Donald Kessler and Burton Cour-Palais in the Journal of Geophysical Research predicting that collisions in low Earth orbit would come within decades and that debris would overtake meteoroids as the main hazard by about 2000.

2015 paper by Robert Rovetto in Earth Science Informatics presenting an ontological architecture for data on orbital debris and space situational awareness.

Sequential number given by the US military to every object it tracks in orbit, starting with Sputnik 1's rocket (1) and satellite (2). It ran out of five digits on 11 July 2026, forcing the 'Alpha-5' workaround and a move to nine-digit formats.

Identifier for a spacecraft by launch year, launch number and piece, such as 1990-037B for the Hubble Space Telescope; in use since 1963, replacing a Greek-letter scheme from Harvard.

NORAD's fixed-width text format for an object's orbit, read with the SGP4 model published in 1980; still the most shared orbital data, though its five-digit catalogue field overflowed and the CCSDS Orbit Mean-Elements Message has been used alongside it since 2020.

The geodetic reference system of 1984 behind GPS: the shape of the Earth and origin against which most latitudes and longitudes on the Web, from the W3C Geo vocabulary to GeoJSON, are given.

Small RDF vocabulary from January 2003 for points with latitude, longitude and altitude, made in the W3C Semantic Web Interest Group; never a W3C standard, it became the most used way to give a thing a position in RDF.

JSON format for geographic features, first specified by a community group in 2008 and standardised as RFC 7946 in August 2016, which dropped other coordinate systems in favour of WGS 84 alone; the developers' favourite, with no RDF in it.

OGC standard, version 1.0 from 2012 and 1.1 from January 2024, that adds a vocabulary for geometries to RDF and spatial functions and relations to SPARQL, so queries can ask what is within, near or touching what.

Open encoding, published by Google in October 2014, that turns coordinates into short codes such as 8FVC9G8F+6X; a free alternative to proprietary address grids.

Joint W3C and OGC guidance, first published in 2017, for putting spatial data on the Web rather than in downloads; its first practice is to give places and spatial things persistent HTTP URIs.

Joint W3C and OGC ontology, a Recommendation of 19 October 2017, for describing sensors, actuators, observations and samples, with the lightweight SOSA core for simple use; a 2023 edition has been in draft since September 2025.

The UN's register of space objects, kept since the early 1960s and, under the 1974 Registration Convention, filled by launching states with each object's designator, launch date and site, basic orbit and function. It depends on states reporting, so it lags and has gaps.

Early geographic information system built for the Government of Canada from the early 1960s to store and analyse the Canada Land Inventory; it ran until the late 1980s.

T. S. Kelso's service, begun as a bulletin board in 1985, that republishes the US military's satellite catalogue and orbital elements for the public; it is now a non-profit.

The US Space Force's website for orbital data on tracked objects, open to registered users since 2004; classified and military objects are withheld or obscured.

Volunteer-made map of the world, started in 2004 because Britain's Ordnance Survey would not release its data under a free licence. Its features carry free-form key=value tags, a folksonomy steered by a wiki, and its data moved to the share-alike ODbL in 2012.

Database of more than 25 million place names, founded in 2005 and published under a Creative Commons attribution licence. Each place has a stable URI that returns a web page or RDF, with links to Wikipedia, which made it the usual place identifier in linked data.

EU directive of 14 March 2007 requiring member states to publish their environmental spatial data in common, interoperable forms, building a shared European spatial data infrastructure.

Proprietary system, launched in July 2013, that names every 3-metre square on Earth with three words. Widely adopted by British emergency services, it is criticised for its closed, patented algorithm, takedowns of reimplementations and addresses that are easily confused.

The US Office of Space Commerce's civil service for space situational awareness, which began sending collision warnings to beta users through Space-Track in September 2024; it moves basic space-traffic data from the military to a civil agency.

Open gazetteer of ancient places, built from the Barrington Atlas of the Greek and Roman World by NYU's Institute for the Study of the Ancient World and the Ancient World Mapping Center; each place has a stable URI, and its data is CC BY.

Standards body for geographic information, founded in 1994 as the OpenGIS Consortium; it publishes WMS, GML, KML and GeoSPARQL.

Non-profit registered in England and Wales, set up in April 2006 to support OpenStreetMap; it is funded mostly by donations.

American geographer and pioneer of computer cartography, whose 1970 paper stated the first law of geography.

English geographer who studied the feasibility of computer mapping for Canada's land inventory in the early 1960s, leading to the Canada Geographic Information System; he is credited with coining the term 'geographic information system'.

American NASA astrophysicist who showed in 1978, with Burton Cour-Palais, that colliding satellites could create a self-sustaining debris belt.

Swiss software engineer who founded GeoNames in 2005.

British programmer who started OpenStreetMap in 2004 at University College London.

Co-author of RFC 7946 (2016), the IETF standard for GeoJSON.

NASA scientist and co-author of the 1978 paper on collisions between artificial satellites.

Co-author of RFC 7946 (2016), the IETF standard for GeoJSON.

Met Office data architect and editor of the joint W3C–OGC Spatial Data on the Web Best Practices.

Geographic information scientist who co-edited the drafts of the OGC GeoSPARQL standard in 2011.

Geographic information scientist, then at the University of California, Santa Barbara, who edited the Semantic Sensor Network Ontology (2017) and GeoSPARQL 1.1 (2024).

Geonovum standards specialist and editor of the Spatial Data on the Web Best Practices.

Co-author of RFC 7946 (2016), the IETF standard for GeoJSON.

Oracle engineer who co-edited the OGC GeoSPARQL standard, from the 2011 drafts to version 1.1 (2024).

University of Surrey researcher and editor of the Spatial Data on the Web Best Practices.

Researcher who proposed ontologies for orbital debris and space situational awareness data from 2015.

Co-author of RFC 7946 (2016), the IETF standard for GeoJSON, and an associate editor of the Pleiades gazetteer of ancient places.

CSIRO scientist who edited the Semantic Sensor Network Ontology (2017) and GeoSPARQL 1.1 (2024).

Co-author of RFC 7946 (2016), the IETF standard for GeoJSON.

US Air Force veteran who has run CelesTrak since 1985, first as a bulletin board in his spare time, republishing the US satellite catalogue and orbital elements for the public.

Co-author of RFC 7946 (2016), the IETF standard for GeoJSON.

Researcher in geospatial semantics at Mainz University of Applied Sciences, editor of GeoSPARQL 1.1 and of the later Spatial Data on the Web Best Practices.

Managing editor of Pleiades, the gazetteer of ancient places, at New York University's Institute for the Study of the Ancient World.