GIS data sources, tools, and references

ESRI's global topographic basemap with detailed roads, place names, and terrain shading. Served as WMTS tiles.

High-resolution satellite and aerial imagery worldwide. Provided by Maxar, Earthstar Geographics, and others.

USGS 7.5-minute topographic quadrangle maps for the USA. Includes topo lines, trails, and hydrography.

USGS orthoimage basemap covering the USA. Also available as Imagery+Topo composite.

ESRI hillshade, dark hillshade, and shaded relief tiles. Useful as semi-transparent overlays to enhance terrain perception.

Global geologic map tile service from the University of Wisconsin-Madison. CORS open, zoom 0–12. Also provides REST query API.

Daily situation maps of the Western Front prepared by the operations staff (G-3) of the First U.S. Army Group, later the Twelfth Army Group, showing Allied and Axis troop positions from D-Day (June 6, 1944) to July 26, 1945. Originals are held by the Library's Geography and Map Division. The scans are served as tiles through the Library's IIIF image service; four of them (D-Day, Liberation of Paris, Battle of the Bulge, and the Allied Advance into Germany) can be opened full-size from the Historical Documents gallery on the Historical page. U.S. Government works.

Digitized maps of the American Civil War era, assembled from the Library of Congress Geography and Map Division together with the Virginia Historical Society and the Library of Virginia. Four battle maps from the Geography and Map Division (Gettysburg, Antietam, Chancellorsville, and the Siege of Vicksburg) can be opened full-size from the Historical Documents gallery on the Historical page, served through the Library's IIIF image service. The Library states that its digitized Geography and Map Division collections are free to use and reuse unless an item carries a Rights Advisory.

Archive of global satellite imagery snapshots from 2014 to present, updated monthly. 193 releases available as free tile layers. Used in AeroPlanimetry's Historical Imagery viewer.

Over 147,000 historical maps online, covering the 16th through 21st centuries. Each georeferenced map can be overlaid on modern maps via the Georeferencer viewer. Free public access. AeroPlanimetry’s Historical page shows 110 of the georeferenced maps (1680–1922) as overlay layers, with the Rumsey Map Center’s permission. Their map tiles come from the Rumsey Map Center’s Geogarage-hosted tile server (tiles-rumsey.geogarage.com).

Thousands of digitized historical maps including Civil War maps, Sanborn fire insurance maps (showing historic city layouts), and exploration-era cartography. Free to view and download.

Aggregator for historical maps from libraries and archives worldwide. Search by geographic area and time period. Maps sourced from institutions including the British Library, David Rumsey, and national archives.

The Institut Géographique National (IGN) serves France's complete historical cartographic archive via WMS/WMTS. Used on the Historical Maps page: Carte de Cassini (1750–1815, first triangulated national survey of France), Carte de l'État-Major 1:40,000 (1820–1866), SCAN50 topographic series (1950s), Paris large-scale maps, and WWI tactical maps of the Verdun sector (1916). Served under the Licence Ouverte / Open Licence Etalab.

High-definition digitisation of the Cassini map (1750–1815) in partnership with the Bibliothèque nationale de France. The Cassini map was the first complete geometrically consistent survey of a nation, covering all of France at 1:86,400 scale over 182 sheets. The BNF HD version provides significantly richer tile detail than the standard IGN Cassini WMS.

Six georeferenced WWI tactical maps of the Battle of Verdun (1916) at 1:10,000–1:40,000 scale, covering: overall Verdun environs, French front lines, defensive organisations, attack positions (April 1916), Fort Douaumont approaches, and Verdun Nord sector. Exceptionally rare primary-source military cartography digitised and georeferenced by IGN. Used on the Historical Maps page.

IGN's broader WWI cartographic collection spanning the entire Western Front in France and Belgium (1914–1918). Military topographic maps showing trench networks, fortifications, and the evolving front lines at various scales. Primary-source military geography digitised and georeferenced by IGN. Used on the Historical Maps page.

Georeferenced black-and-white aerial photographs of France taken by IGN between 1950 and 1965, capturing the country during postwar reconstruction. Complete national coverage at high resolution, invaluable for studying urban development, agricultural patterns, and landscape change. Used on the Historical Maps page.

Archive of ESRI World Imagery tiles at specific historical snapshot dates, enabling before/after satellite imagery comparison. The site uses a fixed 2026 snapshot as a reference basemap on the Historical Maps page for comparison with older cartographic layers. Freely accessible via Esri's ArcGIS Living Atlas.

A community-built, editable map of the world through history, with a time slider for browsing places and borders at different dates. The data is dedicated to the public domain (CC0); credit to OpenHistoricalMap contributors is requested. It is published as vector tiles only (no raster tiles), so it is viewed on its own website rather than as a layer here. Anyone can create a free account to add or correct features.

The outlines of the wildfires that are active now, from the National Interagency Fire Center (ArcGIS feature service, public domain, no key). Shown on the USA page as outlines coloured by percent contained; click one for the fire’s name, size, containment, location, cause, and dates. The site loads a simplified copy through its own relay (the full-detail answer is over 8 MB) and reloads it every 15 minutes while the layer is on. An earlier test listed this service as unavailable because the query parameters were wrong; it works. The popup also links to the fire’s page on InciWeb, the interagency incident information site (U.S. government public information), when InciWeb’s index lists a page with the same name in the same state that began around the time the fire was discovered; our server reads InciWeb’s index and the page’s date of origin, and the link opens InciWeb itself.

What-if inundation maps from NOAA's Sea Level Rise Viewer for the US coast, served as cached tiles (coast.noaa.gov): areas that could be flooded with 1, 3, 6, or 10 ft of sea level rise above the average high-tide line, with flood depth and low-lying areas (zoom 0–16). The service also offers half-foot steps from 0 to 10 ft, mapping-confidence and marsh-migration layers. NOAA calls it a screening-level planning tool, not for navigation, permitting, or legal purposes. U.S. Government work, public domain; credit NOAA Office for Coastal Management.

National Park System unit boundaries from the NPS ArcGIS services (mapservices.nps.gov). They power the query-only "USA — National Park Boundaries (NPS)" layer: switch it on and click anywhere to see whether you are inside a park unit. The NPS server does not answer direct requests from outside the agency, but it works through this site's own server. U.S. Government work, public domain.

Multi-Radar/Multi-Sensor (MRMS) base reflectivity mosaic at 1 km resolution, updating every ~5 minutes. Covers CONUS, Alaska, Caribbean, Guam, and Hawaii. ArcGIS MapServer export, no key required, CORS-enabled.

Annual AIS vessel traffic density for US waters (2009–2024). REST-based tile cache services, CC0 1.0 licensed. Shows aggregate shipping patterns at national to harbour scale. Query Feature returns the 2024 transit-count class.

USGS portal for topographic, hydrology, boundaries, and elevation data. Source for topo quads, NHD, WBD, and more.

High-resolution National Hydrography Dataset. Streams, rivers, waterbodies for the USA.

Hydrologic unit boundaries at multiple scales (HUC4 through HUC12) for the USA.

National geologic map of the USA compiled from state surveys. Tile display only — no identify endpoint available.

Active and potentially active faults and folds in the USA. Queryable — returns the fault name, section, age, and slip rate.

Real-time earthquake data, historic events, and tectonic plate boundary layers. Updated continuously.

National Land Cover Database (NLCD 2021) classifying USA land use into 20 categories via WMS GetFeatureInfo.

USDA NRCS soil map units for the USA. Visual display only — query via SDMDataAccess WMS.

Wetland type and classification for the USA. Queryable at zoom 12+. Covers all 50 states.

Final and proposed critical habitat designations for threatened and endangered species.

Monitoring Trends in Burn Severity (MTBS) — all fire perimeters in the USA since 1984.

Real-time weather watches, warnings, and advisories. Updates continuously from National Weather Service.

Multi-Radar Multi-Sensor 24-hour quantitative precipitation estimate. Real-time radar-based rainfall data. Query Feature returns the rainfall in inches and millimetres.

Census Bureau geographic boundaries — states, counties, congressional districts, and more. A useful source for boundary data; this site does not use it at present.

Forest Service Enterprise Data Warehouse — National Forest boundaries, Ranger Districts, MTBS fire history, and more.

National Agriculture Imagery Program — high-resolution aerial photography for the contiguous USA (about 0.6 m pixels), updated every 1–3 years, shown through the USGS National Map NAIP Imagery service. Zoom 6–16. Query Feature returns the capture date, ground resolution, and vendor of the most recent image. Credit: “USGS, USDA, The National Map: Orthoimagery”.

High-voltage electric power transmission lines across the USA. A useful source for power-grid data; this site does not use it at present.

Federal land boundaries — National Parks, Wilderness, BLM, USFWS, Military, Native American areas. Query Feature (zoom 5+) returns the name and area of the park, monument, forest, wilderness, grassland, refuge, BLM, military, or tribal land. The Counties layer (zoom 7+) comes from the same service: county names and boundaries from the Census Bureau, with Query Feature for the county, state, FIPS code, 2020 population, and area.

The official national inventory of parks, wildlife refuges, forests, wildlife management areas, easements, and other protected land (version 3.0, 2022), shown as three map-tile views: by managing agency, by GAP protection status (how much the land is managed for biodiversity), and by public access. Tiles come from the USGS Gap Analysis Project’s ArcGIS Online service (zoom 4–10, enlarged beyond that, so boundaries are approximate when zoomed in close); Query Feature reads the name, designation, manager, status, access, and area from its hosted layer, listing overlapping areas. Public domain; credit “USGS Gap Analysis Project, PAD-US”. A newer PAD-US version exists but its USGS map service was not answering when tested.

The EPA’s ecoregion framework for the conterminous United States: 105 Level III regions and about 970 Level IV subdivisions of similar geology, soils, vegetation, and climate, a common basis for habitat, wildlife, and water-quality work (December 2011 edition). Drawn through the site’s own server from the EPA geodata service, with a Query Feature lookup of the region name and code. Alaska and Hawaii are not in this service. The EPA server is sometimes slow. Public domain; credit “U.S. EPA Office of Research and Development”.

Three hosted feature services of the U.S. Fish and Wildlife Service: the four waterfowl flyway boundaries (Migratory Bird Program), the simplified outer boundaries of the National Wildlife Refuge System (1,085 polygons: National Wildlife Refuges, Waterfowl Production Areas, National Fish Hatcheries, and other units; Division of Realty), and the designated and proposed wilderness on refuges and other Service lands (392 polygons including Alaska and the territories). The features are asked for by view through the site’s own server and drawn by the page, with a Query Feature lookup from the features in memory. Public domain; credit “U.S. Fish and Wildlife Service”.

Critical habitat designated or proposed under the Endangered Species Act by NOAA Fisheries for marine and anadromous species (salmon and other fish, corals, sea turtles, whales, seals and sea lions): the merged polygon layer for Section 7 consultations, generalized, 2,156 polygons including Hawaii, Alaska and the Pacific territories, and its companion line layer (59,888 river-reach lines, drawn from zoom 10). Asked for by view through the site’s own server and drawn by the page, with a Query Feature lookup that lists every unit at the click, areas and lines together. Public domain; credit “NOAA Fisheries”. Habitat of land and freshwater species is the USFWS Critical Habitat layer.

BLM-designated Areas of Critical Environmental Concern on public lands in the western USA. Query Feature (zoom 4+) returns the area name, land use plan, size, and state.

Global soil property predictions — pH, clay%, sand%, and organic carbon at depth intervals. Point-based REST API.

Utah 1:500,000 geologic map with rock unit identification. Queryable at zoom 7+.

Texas 1:250,000 Geologic Atlas with rock unit identification and geologic ages.

California geologic map and fault activity map. Query Feature (zoom 5+) returns the rock type, age, and description, or the fault name, type, and age class.

California Wildlife Habitat Relationships (WHR) vegetation map from CAL FIRE's Fire and Resource Assessment Program. ArcGIS MapServer export, zoom 0–15. Licensed CC BY 3.0: cite CAL FIRE as the source and note any changes to the data. Query Feature (zoom 5+) returns the vegetation type and class.

The California Department of Transportation publishes the details of its roadside CCTV cameras (about 3,400 in service, all 12 districts) as open JSON through its Web Weather and Cameras (CWWP) data service, at no charge. The USA page’s California Highway Cameras layer lists them through our server (cached 30 minutes); the picture itself is loaded by your browser straight from Caltrans when you click a camera. Caltrans does not archive the live pictures and neither does this site. Credit: camera pictures courtesy of Caltrans.

The Massachusetts Department of Transportation (MassDOT) makes the MBTA’s real-time vehicle positions (buses, subway, light rail, commuter rail and ferries, about 500 vehicles at a time) available in the GTFS Realtime format without a key. The USA page’s Boston Live Public Transport layer asks for them through our server (cached 20 seconds) and reads line names from the MBTA’s GTFS timetable file. Terms: the MassDOT Developers License Agreement grants non-exclusive, limited and revocable rights to use, reproduce and redistribute the data; MassDOT must be acknowledged as the provider, its and the MBTA’s logos and trademarks are not used, and the data are provided as is without a guarantee of accuracy. This site is not affiliated with MassDOT or the MBTA.

The City of Austin, Texas publishes the locations of its traffic cameras and the address of each camera’s current picture on its open data portal. The USA page’s Austin Traffic Cameras layer lists the roughly 800 cameras that are switched on through our server (cached 30 minutes); the picture itself is loaded by your browser straight from the City of Austin when you click a camera. Licence: Public Domain (as stated on the dataset). Credit: City of Austin, Texas - data.austintexas.gov.

WellSTAR well locations from the California Department of Conservation’s CalGEM: oil, gas and geothermal wells, drawn as an ArcGIS MapServer layer; Query Feature (zoom 12+) returns the well details. Licence: public domain as recorded for the layer. Credit: © California Dept. of Conservation, CalGEM.

Long-term relative sea level trends at about 500 tide gauges (144 US stations plus 365 elsewhere), published as JSON by NOAA's Center for Operational Oceanographic Products and Services. The site fetches it through its own server and draws each station as a coloured circle on the Global and USA maps (the "Global — Sea Level Trends" layer); a click shows the trend, its uncertainty, the record length, and a link to NOAA's station page. The trend includes vertical land movement at the gauge. U.S. Government work, public domain.

Daily 5 km coral bleaching heat stress products from NOAA Coral Reef Watch (version 3.1): the Bleaching Alert Area and Degree Heating Weeks layers on the Global page. They are requested through the site's own server from the Pacific Islands Ocean Observing System's ERDDAP (pae-paha.pacioos.hawaii.edu), which only serves a latitude/longitude grid, so the layers load only at zoom 5–10. Query Feature returns the alert level and Degree Heating Weeks from the same data service. U.S. Government work, public domain; credit NOAA Coral Reef Watch.

The University of Maryland GLAD lab's global tree cover loss 2001–2024 (version 1.12, 30 m, for land with more than 30% tree canopy in 2000), served as map tiles by Global Forest Watch (tiles.globalforestwatch.org) and shown on the Global page (zoom 0–12). The tiles are large, so it loads slowly. CC BY 4.0; credit Hansen/UMD/Google/USGS/NASA via Global Forest Watch.

The Space Weather Prediction Center's OVATION model forecast of the probability of visible aurora 30–90 minutes ahead, for both hemispheres, published every 5 minutes as a 1° grid in JSON. The site fetches it through its own server and draws it as a live overlay, the "Global — Aurora Forecast" layer, on the Global page and on the regional pages where it matters (USA, Canada, South America, Europe, Australia, and New Zealand). U.S. Government work, public domain.

NOAA’s nowCOAST web map services (OGC WMS, no key). Lightning Strike Density: lightning in the latest 15 minutes on an 8 km grid for the Pacific and the Americas, derived from the NLDN and GLD360 networks (USA and Global pages; Query Feature gives the strike density). Global satellite mosaics: NOAA/NESDIS GMGSI hourly infrared, water vapor, and visible composites at about 3 km resolution, 2 to 3 hours old (Global page). GOES Infrared, Visible, Water Vapor, and Shortwave Infrared: GOES-East and GOES-West regional imagery at 0.5 to 2 km with a new picture about every 5 minutes, usually less than 15 minutes old, covering about 180°W to 51°W and 11°N to 51°N (USA page; these layers can be played with the Weather Timeline). U.S. Government products; the lightning layer is a derived density map, not the raw lightning data.

CelesTrak (Dr. T.S. Kelso) publishes the current orbital elements of tracked satellites, derived from U.S. Space Force tracking. The Global page’s Space Stations layer uses the sets for the International Space Station and China’s Tiangong station, and its Satellites layer the weather, GPS, Galileo and bright (visual) groups: our server fetches each from CelesTrak at most every 2 hours, and your browser turns them into positions every second with satellite.js (the SGP4 model, MIT licence). In testing the ISS position agreed with an independent live position to within half a kilometre. Free to use; CelesTrak asks users to credit it and not to fetch the same data more often than every couple of hours.

adsb.lol aggregates the ADS-B transmissions (the position signal most aircraft broadcast) received by volunteers’ ground stations and publishes them as open data through a free API. The Global page’s Military Aircraft layer (the military-registered aircraft the network sees worldwide, usually 100 to 250) and Live Aircraft layer (every aircraft in view at zoom 7 or closer, coloured by altitude) use it. The API is rate limited and refuses some requests at random, so our server asks for fixed 5-degree areas, caches each answer for 20 seconds, serves the last good copy when adsb.lol refuses, and your browser moves each aircraft along its own heading and speed between updates. Aircraft on the LADD and PIA privacy lists are left out. Coverage is good over Europe and North America and thin elsewhere. Licence: Open Database License (ODbL) 1.0, credit: Aircraft data © adsb.lol contributors. The operator asks anyone using the API in production to get in touch, and an API key may be required in future.

Wikidata, the Wikimedia Foundation’s open knowledge base, lists 45 well-known reported UFO incidents (items that are instances of “UFO sighting”), from the Irish annals of about 740 AD to 2007. The Global page’s Notable UFO Incidents layer draws them from a static file on this site built from a Wikidata query: where Wikidata has a coordinate it is used, otherwise the named place, and for 11 incidents the position was placed from published accounts; five whose exact place is unknown are drawn as approximate areas. It is a map of famous cases, not of sightings in general: the large sighting databases (NUFORC, BFRO and GEIPAN) do not allow their data to be reused. Wikidata data are CC0 (public domain).

The Space Devs’ Launch Library 2 is a community-maintained database of rocket launches, launch pads, rockets and missions. The Global page’s Rocket Launches layer shows the last 40 and next 40 launches at their pads. Our server asks for them twice every 30 minutes (the free allowance is 15 requests an hour), keeps the answer for 30 minutes and serves the last good copy if the service refuses. Terms: free to use in any way, attribution encouraged, and do not forward the data without adding value (here: the map).

Radio Browser is a community directory of internet radio stations with their countries, tags, stream addresses and positions; its directory data are public domain (PDDL 1.0). The Global page’s World Radio Stations layer shows the 2,500 most listened-to stations that have a position and a plain MP3, AAC or Ogg stream over HTTPS, refreshed from one of the directory’s mirrors every 6 hours. When you press Listen, your browser connects straight to the broadcaster, whose own stream terms apply and who can see your IP address; nothing is relayed or recorded by this site.

Near-real-time satellite tiles from NASA's Global Imagery Browse Services: GOES-East and GOES-West GeoColor from NOAA (the Americas and the Pacific; USA, Canada, South America, and Global pages), Himawari infrared from the Japan Meteorological Agency (Asia, Japan, Australia, New Zealand, and Global pages), and the global rainfall rate from NASA's IMERG precipitation product (Global, Asia, South America, Africa, Australia, Japan, and New Zealand pages; 30-minute, about 4 hours behind). Query Feature reads a value at the click for the Himawari and IMERG layers by matching the map colour to NASA's published colour table. The geostationary layers update about every 10 minutes. The Global page also has more products of the same satellites (GOES-East and GOES-West Red Visible, Dust, Fire Temperature, and Air Mass; Himawari Red Visible and Air Mass) and two daily true-colour mosaics at about 250 m (VIIRS on NOAA-20 and MODIS on Terra), which the page points at the newest complete day. Two Recent Imagery layers (A and B) draw NASA's 30 m HLS tiles (Harmonized Landsat Sentinel-2) for a date chosen in the Recent Imagery window; the list of dates and their cloud cover comes from NASA's CMR catalogue through the site's own server. The Global page also has daily sea surface temperature anomaly and sea ice concentration layers from the NASA JPL MUR analysis, and monthly snow cover, land surface temperature, vegetation greenness, and methane maps from MODIS and AIRS. Loaded straight from GIBS. NASA open data; credit NASA GIBS and the data originators.

Esri's 15 m TerraColor satellite imagery of the Antarctic region (Earthstar Geographics), a cached tile service in the Antarctic Polar Stereographic projection (EPSG:3031). It is the default base map on the Antarctica page and is loaded through the site's own Esri relay, which holds the API key. Real image detail ends at zoom 13. Used under the Esri Master Agreement; credit Esri and Earthstar Geographics.

The Antarctica page uses NASA GIBS's Antarctic polar (EPSG:3031) web map service for Blue Marble with shaded relief and bathymetry, Blue Marble, the daily MODIS Terra true-colour image, and the MEaSUREs ice velocity map, an InSAR-based map of how fast the Antarctic ice flows made by Rignot, Mouginot and Scheuchl and distributed by the National Snow and Ice Data Center. The images are requested straight from GIBS. The GIBS sea ice concentration layers were left out because their newest image is from September 2025, and the daily sea ice extent layers are too patchy to be useful. NASA open data; credit NASA GIBS, NASA MEaSUREs and NSIDC.

The Polar Geospatial Center (University of Minnesota) runs public ArcGIS map services in the Antarctic polar projection. The Antarctica page uses two of them, loaded straight from the Center: the Antarctic Composite Basemap (the 15 m Landsat Image Mosaic of Antarctica from USGS, the British Antarctic Survey and NASA, with a 250 m MODIS mosaic south of 82.5°S) and the Reference Elevation Model of Antarctica (REMA, Howat and others, 2019), drawn live as a shaded relief and as a colour-by-height relief. Terrain graphics are credited as “DEM(s) courtesy of the Polar Geospatial Center”. Acknowledgement required by the Center: Geospatial support for this work provided by the Polar Geospatial Center under NSF-OPP awards 1043681, 1559691, 2129685, and 2434541. The REMA DEMs were provided by the Byrd Polar and Climate Research Center and the Polar Geospatial Center under NSF-OPP awards 1043681, 1542736, 1543501, 1559691, 1810976, and 2129685. The Center also hosts scanned USGS topographic maps of Antarctica (1:50,000, 1:250,000, 1:500,000 and 1:500,000 sketch maps; US Government works), which the Antarctica page shows as four overlay layers. The Center’s COMNAP Antarctic Facilities list was not used: COMNAP allows it for educational and non-commercial purposes only.

The SCAR Antarctic Digital Database (ADD) is the continent-wide Antarctic coastline and map-feature collection kept by the Scientific Committee on Antarctic Research and the British Antarctic Survey. The Antarctica page draws two layers from version 7.12 (2025), medium resolution: the coastline lines (rock coast, ice coast, ice shelf front, grounding line, ice rumples) and the ice shelf, ice tongue and ice rumple areas. The British Antarctic Survey publishes the data on ArcGIS Online in the Antarctic polar projection; the site keeps a simplified copy (150 m) in its own folder (antarctica-add.json), so it does not follow later ADD releases. Licensed under Creative Commons Attribution 4.0; credit the SCAR Antarctic Digital Database.

The Australian Antarctic Data Centre’s GeoServer publishes the SCAR Composite Gazetteer of Antarctica (about 39,000 place names with feature type, height and a description). The Antarctica page draws the places as orange dots (images loaded straight from the Data Centre) and, with Query Feature on, looks up the nearest names through the site’s own server. The Data Centre licenses its services under Creative Commons Attribution 4.0; credit SCAR and the Australian Antarctic Data Centre.

Wikidata is a free, community-edited knowledge base whose data is released under CC0 (public domain). The Antarctica page’s Research Stations layer is a snapshot (3 October 2026) of the items that are Antarctic research stations and have coordinates (about 160, current and historic), stored in the site’s own folder (antarctica-stations.json). The list is not official and can lag behind Wikidata.

Layers from the Meteorological Service of Canada's open WMS (geo.weather.gc.ca): the global GDPS forecast model (25 km; 2 m air temperature, 10 m wind, and sea-level pressure, on every map) and the Canadian radar mosaic (1 km rain rate, every 6 minutes; Canada page). Query Feature returns the forecast value (or the rain rate) at the click. No key required. Data Services End-use Licence: commercial use is allowed; credit "Data Source: Environment and Climate Change Canada".

Meteosat Second Generation natural-colour imagery of Europe, Africa, and the Atlantic, served as a WMS (Europe, Africa, and Global pages) and requested as one image per view. EUMETSAT core data are CC BY 4.0; credit "Contains modified EUMETSAT Meteosat data" with the year.

The General Bathymetric Chart of the Oceans' global ocean-depth and land-elevation grid (15 arc-second, about 450 m), shown as an opaque colour map from the British Oceanographic Data Centre's WMS (zoom 0–12) on the Global, USA, Asia, Japan, Australia, and New Zealand pages. Public domain and free for commercial use; the source must be acknowledged. Not for navigation or safety at sea.

The European Commission Joint Research Centre's map of where Landsat satellites have detected surface water since 1984 (occurrence layer, zoom 0–12), shown on the Global, Africa, Asia, South America, and Australia pages. The tiles are hosted on Google Cloud Storage (storage.googleapis.com). CC BY 4.0 under the Copernicus free, full and open data policy; credit "Source: EC JRC/Google" and cite Pekel et al. (2016), Nature 540.

Open dataset of world time zone boundaries (IANA zones) maintained by Evan Siroky and assembled from OpenStreetMap data. It is bundled with AeroPlanimetry to power the World Time Zones overlay on the Global page: 435 zones, with a click showing the zone's IANA name, current UTC offset (daylight-saving aware), and local time. Data © OpenStreetMap contributors, ODbL 1.0; code MIT.

Seafloor depth layer from EMODnet Bathymetry, operated by a European partnership of marine research institutes, national hydrographic services, and survey companies and managed by the European Commission (DG MARE). Shown as an ocean depth overlay on the Global page (maximum zoom 11); Query Feature returns the depth in metres and feet. Publicly available; see the EMODnet terms of use. Cite as: EMODnet Bathymetry Consortium, EMODnet Digital Bathymetry (DTM).

Overlays of marked hiking trails and cycling routes drawn from OpenStreetMap route data. Hiking Trails is available on the Global, Europe, Japan, Australia, New Zealand, and Historical pages; Cycling Routes on the Global and Europe pages. Visual only (no query). Route overlay licensed CC BY-SA 3.0 (Germany); underlying map data © OpenStreetMap contributors (ODbL).

Cycling-oriented map style built on OpenStreetMap data, available on the Global and Europe pages. The style is open source; tiles are served by OpenStreetMap France under a fair-use tile policy. Visual only (no query). Map data © OpenStreetMap contributors (ODbL).

Worldwide nautical overlay of seamarks such as lights, buoys, and beacons, built on OpenStreetMap data. Transparent tiles that appear from zoom 9 near coastlines; available on the Global, Europe, Japan, Australia, New Zealand, and Historical pages. Visual only (no query). Licensed CC BY-SA 2.0; underlying map data © OpenStreetMap contributors (ODbL).

Annual composite of Earth at night from the VIIRS Day/Night Band. Keyless XYZ tiles via NASA GIBS (zoom 0–8). Shows city lights, shipping lanes, offshore gas flares, and fishing fleets. Public domain.

Global geologic map database from the University of Wisconsin-Madison. Returns rock unit name, lithology, and formation description worldwide.

OpenStreetMap's geocoding and reverse geocoding service. Returns location name, country, and address for any coordinate.

Global tectonic plate boundary layer. Queryable — returns plate names and boundary type (convergent, divergent, transform).

Reference overlay with roads, boundaries, and place names worldwide. Used on all regional pages. Also proxies power line queries.

Global roads, railroads, and airports overlay. Visual display only.

Used by the Go to Location toolbar tool. Converts place names to coordinates worldwide.

Official source for Atlantic and Eastern/Central Pacific tropical cyclone advisories. Provides a live CurrentStorms.json feed (positions, intensity, basin) and per-storm KMZ files for 5-day forecast tracks and cones of uncertainty. Used by the Active Tropical Cyclones overlay. No API key required.

U.S. Navy agency issuing tropical cyclone warnings for the Western Pacific, Indian Ocean, and Southern Hemisphere. Warning text files (ATCF format) provide current position, intensity, and 120-hour forecast tracks. Complements NHC data for global TC coverage. Used by the Active Tropical Cyclones overlay.

Near real-time global active fire detection from MODIS (Terra/Aqua) and VIIRS satellites. The MODIS C6.1 24-hour global CSV delivers thermal anomaly locations, fire radiative power (FRP in MW), brightness temperature, and per-detection confidence scores. Updated every 24 hours; no API key required for the CSV feed. Used by the Active Wildfires overlay.

Authoritative global database of ~1,400 volcanoes with confirmed Holocene activity, maintained by the Smithsonian's National Museum of Natural History. Includes eruption histories, volcano classifications, and weekly activity reports. The Holocene volcano list (CC0) forms the basis of the Active Volcanoes overlay.

USGS program providing real-time monitoring and alert levels for U.S. volcanoes using the four-level USGS/VAAC scale (Normal / Advisory / Watch / Warning). Alert levels are used to colour-code U.S. volcanoes in the Active Volcanoes overlay.

NASA JSON API tracking open natural events by category (wildfires, volcanoes, severe storms, sea and lake ice, floods, and more). Used to supplement the volcano overlay with currently active eruptions flagged by NASA satellite observation. Free, no API key required.

Multi-scale Ultra-high Resolution (MUR) Level 4 SST analysis at ~1 km resolution, produced daily by combining MODIS, AMSR2, and other satellite sensors. Warm regions (red/orange on the standard oceanographic colour scale) identify hurricane fuel zones in the tropics. Served via NASA GIBS as a WMS overlay. DOI: 10.5067/GHGMR-4FJ04.

NASA tile and WMS service delivering global satellite imagery products including MODIS true/false colour, sea surface temperature, land surface temperature, snow cover, chlorophyll concentration, and many more. Supports both EPSG:4326 and EPSG:3857 (Web Mercator). Used to serve the SST overlay and MODIS Terra imagery layers.

Bikeshare systems publish station positions and live availability in the General Bikeshare Feed Specification (GBFS); MobilityData keeps a catalogue of the feeds. The Global page’s Bikeshare Stations layer uses the 46 systems (about 12,600 stations: docomo bike share in Japan, Beryl in the UK, many French systems, Helsinki City Bikes, Mobi in Vancouver, OV-fiets in the Netherlands and others) whose own feed names an open licence (ODbL 1.0, CDLA-Permissive 2.0 or Creative Commons). Our server asks each feed at most once a minute for availability and once a day for station positions, and the map shows the licence in each station’s popup. Big-city systems that name no licence in their feed (for example Citi Bike, Divvy, Vélib’) are deliberately not used.

Global Dam Watch is an international initiative that maintains the GDW database of about 41,000 river barriers and their reservoirs (version 1.0, 2024). The Global page’s Large Dams layer shows the 9,200 dams that are 15 m or higher or belong to the GRanD reservoir database, with height, capacity, year, main use and power. The file is cut from the database once by a maintenance script and served from this site, so nothing is requested from Global Dam Watch while you use the map. Licence: Creative Commons Attribution 4.0. Credit: Lehner et al. (2024), The Global Dam Watch database of river barrier and reservoir information for large-scale applications, Scientific Data 11:1069.

Mapillary (part of Meta) hosts crowd-sourced street-level photos. The Global page’s Street-Level Photos layer asks Mapillary’s map tiles, through our server (which keeps the site’s free client token private), for the photo positions of the map area when you are zoomed in to level 15 or closer; a photo is loaded by your browser straight from Mapillary when you click its dot. Licence: the photos are CC BY-SA 4.0 under the Mapillary Terms of Use; Mapillary blurs faces and number plates, and they are never un-blurred here. Credit: Photo © Mapillary contributors, CC BY-SA 4.0, with a link to the photo on mapillary.com.

Panoramax is an open, federated street-level imagery service (software under the MIT licence), run by volunteers and strongest in France and parts of Europe. The Global page’s Street-Level Photos layer draws its pictures as purple dots next to Mapillary’s green ones, so the layer keeps working if one of the two services is down. The positions come from the public Panoramax meta-catalogue (no key) through our server, cached for a day; a picture is loaded by your browser straight from the instance that hosts it when you click its dot. Licence: each picture is CC BY-SA 4.0 or Licence Ouverte 2.0 (the only two licences Panoramax instances accept) and is shown with its producer’s name; the services blur faces and number plates. No service guarantee.

Taiwan's national mapping agency: the English transparent Taiwan e-map (WMTS, zoom 0–19) and the Taiwan orthophoto mosaic (WMS, zoom 6+), both on the Asia page. The aerial layer loads only when the view includes Taiwan. Open Government Data License, version 1.0; credit the center. No key or registration.

The Survey and Mapping Office of Hong Kong’s Lands Department provides its base map, aerial imagery and place-name labels as open XYZ tile services (the Base Map, Aerial Imagery and Place Names layers on the Asia page, zoom 10–20). The tiles are loaded by your browser straight from the Government’s server. Terms: CSDI Portal Terms and Conditions, section 3 allows free commercial and non-commercial use if the Government and the CSDI Portal are credited as the source; the Department’s API pages additionally require its logo on the map face and a copyright notice, which the map shows in a corner while a Hong Kong layer is on (the logo file was supplied by the Department for this purpose). No warranty of accuracy; the terms may change without notice. No key or registration.

Volunteers across the United States and Canada count the birds at their feeders from November to April. The raw data (version 4, February 2026) are published on Mendeley Data under CC0 1.0, a public domain dedication, so no permission is needed. The USA and Canada pages’ Feeder Birds layer shows the 2021 to 2025 seasons (about 40,000 count sites, 1.2 million counts) summed into map cells of 0.25 to 2 degrees, coloured by the most reported species; each cell holds at least five count sites and no individual feeder or yard is shown. The summary is made once by a maintenance script and served from this site, so nothing is requested from Cornell while you use the map. Species names come from the FeederWatch species translation table. Credit: Project FeederWatch, Cornell Lab of Ornithology and Birds Canada; Bonter, D. N., & Greig, E. I. (2021), Frontiers in Ecology and Evolution 9:619682.

The national orthophoto of the Czech Republic (about 12.5 cm pixels, WMTS tile cache, zoom up to 20), on the Europe page. It draws only over Czechia. CC BY 4.0; no registration.

Australia's national topographic map at 1:250,000 as a tile cache (zoom 0–12), on the Australia page. CC BY 4.0; © Commonwealth of Australia (Geoscience Australia). Query Feature (zoom 5+) returns the name and type of nearby map features.

Annual AIS-based vessel density for EU waters and adjacent areas (1 km² grid, hours/km²/month, 2017–present). Free for commercial and non-commercial use with attribution. WMS endpoint. On the Europe page, Query Feature returns the hours of ship traffic per km² per month.

Austria's official open government basemap, a joint project of Austrian public authorities. Standard map and 30 cm orthophoto (aerial) layers as WMTS tiles, zoom 0–20. Credit: “Datenquelle: basemap.at”.

Federal Agency for Cartography and Geodesy (Bundesamt für Kartographie und Geodäsie). TopPlusOpen is licensed dl-de/by-2-0 (Data Licence Germany – Attribution 2.0); basemap.de Web Raster, the joint federal–state topographic basemap, is CC BY 4.0. WMTS tiles, zoom 0–18.

Administration du Cadastre et de la Topographie — the national topographic map and the latest orthophotos (aerial imagery) from the Geoportail open-data WMTS. Published under CC0.

Dutch national spatial data platform (Publieke Dienstverlening Op de Kaart) — the BRT Achtergrondkaart topographic background map, current RGB aerial photography, and colour-infrared (CIR) aerial imagery at standard and high resolution. WMTS tiles, zoom 0–19.

Norwegian Mapping Authority — the national topographic map (Topografisk norgeskart) from Kartverket's open WMTS tile cache, zoom 0–18.

Instituto Geográfico Nacional — the IGN base map (Base cartográfica IGN) from the national WMTS service, zoom 0–20. Credit: “© Instituto Geográfico Nacional de España”.

Federal Office of Topography — the Pixelkarte national map and SWISSIMAGE orthophotos from the geo.admin.ch WMTS, zoom 0–19. Open Government Data; credit “© swisstopo”.

Land Information New Zealand — aerial imagery, topographic raster, and hillshade for NZ.

NSW government property boundaries (cadastral parcels). Queryable at zoom 12+.

Queensland government administrative boundaries and cadastral land parcels.

Canada Base Map, Toporama topographic map, and CanVec vector topography. Also provides CLSS administrative boundaries (Aboriginal Lands, National Parks). WMS services. Toporama zoom 7–16, CanVec zoom 8–16.

The National Road Network (NRN) from the GeoBase series — a transparent overlay of Canada's roads, from highways to local streets, including British Columbia. Open Government Licence – Canada; credit “Statistics Canada”. Zoom 6–18. Query Feature returns the road name, class, route, municipality, and province.

Government of the Northwest Territories vector base map (scales 1:25,000,000 to 1:1,000), compiled from public GNWT and Government of Canada datasets. GNWT open data is released under the Open Government Licence – Northwest Territories. Zoom 0–14.

Brazilian Institute of Geography and Statistics — state and municipal boundaries via WMS/WFS.

Peru Institute of Geology, Mining, and Metallurgy — base map, geology, political boundaries, and mining cadastre.

Uruguay's national spatial data infrastructure, run by AGESIC — the IDEuy base map (zoom 6+) and the national aerial photo mosaic from the 2017–2018 flight (zoom 7+), both as WMS image services. Open data under the Licencia de Datos Abiertos – Uruguay; credit “IDEuy (AGESIC)”.

GSI Maps tiles: standard and English maps, aerial photography, relief and hillshade, plus thematic layers — red relief image map, active faults, volcanic land conditions, flood-control land classification, lakes and ponds, and historical aerial photographs (1945–50, 1961–69). Free to use, including commercially, under GSI's Terms of Use (Public Data License 1.0, compatible with CC BY 4.0) with a source credit.

Japan 1:200,000 geologic map from the National Institute of Advanced Industrial Science and Technology.

OpenStreetMap-based topographic map with contours. Good Africa coverage. XYZ tiles. Now used on the Africa page.

OSM-based humanitarian map style widely used in crisis response across Africa. XYZ tiles. Now used on the Africa page.

United Nations OCHA web topographic basemap. ArcGIS REST endpoint. Now used on the Africa page. Query Feature (zoom 3+) returns the country or territory and the nearest populated place.

FEMA FIRM flood zone maps for the USA. Functional on Linux hosting but blocked on Windows due to TLS 1.3 incompatibility with Python's HTTP proxy.

Transport for London’s open data service publishes about 800 live traffic cameras (JamCams) through its Unified API. The Europe page’s London Traffic Cameras layer lists them through our server (cached 30 minutes); the picture is loaded by your browser straight from TfL when you click a camera. Licence: Open Government Licence v2.0 with TfL’s amendments (commercial use allowed, acknowledgement required): Powered by TfL Open Data. Contains OS data © Crown copyright and database rights 2016 and Geomni UK Map data © and database rights 2019. TfL logos are not used and TfL does not endorse this site.

Fintraffic’s Digitraffic service publishes about 800 road weather camera stations along Finland’s roads (several views per station). The Europe page’s Finland Road Weather Cameras layer lists them through our server (cached 30 minutes; Digitraffic requires gzip and an identifying header, which our server sends); the picture is loaded by your browser straight from Digitraffic. The Live Road Traffic layer also uses Digitraffic’s road traffic measuring stations (about 500 stations; the 5-minute average speed, its share of the free-flow speed and the vehicles per hour in each direction), asked for through our server and cached for a minute. Licence: Creative Commons Attribution 4.0. Credit: Source: Fintraffic / digitraffic.fi, license CC 4.0 BY.

DriveBC (Government of British Columbia) publishes about 1,000 highway webcams as open data. The Canada page’s British Columbia Highway Cameras layer lists them through our server (cached 30 minutes; cameras marked stale or switched off are left out); the picture is loaded by your browser straight from DriveBC, and a camera’s own credit or delay notice is shown with it. Licence: Open Government Licence – British Columbia. Credit: Contains information licensed under the Open Government Licence – British Columbia.

The City of Calgary publishes about 200 intersection and roadside traffic cameras on its Open Calgary data portal (dataset k7p9-kppz). The Canada page’s Calgary Traffic Cameras layer lists them through our server (cached 30 minutes); the picture is loaded by your browser straight from the City. Licence: Open Government Licence – City of Calgary (v2.1), commercial use allowed. Credit: Contains information licensed under the Open Government Licence – City of Calgary.

Ontario 511 (Ministry of Transportation of Ontario) publishes its highway cameras through a developer API for which the Ministry issues a free key after reviewing the request. The Canada page’s Ontario Highway Cameras layer lists them through our server, which keeps the key private (cached 30 minutes; cameras that are switched off are left out); the picture is loaded by your browser straight from Ontario 511. Licence: Open Government Licence – Ontario, under the Ontario 511 Developer’s Access Agreement. The data are provided “as is” and “as available”, and the layer says so with each picture. Credit: Contains information licensed under the Open Government Licence – Ontario.

The Norwegian Public Roads Administration publishes its road camera table (DATEX II) as open data through an OGC API Features service, and the pictures are served from kamera.atlas.vegvesen.no. The Europe page’s Norway Road Cameras layer lists the working cameras (about 860; cameras the agency reports as faulty are left out) through our server, cached 30 minutes; the picture is loaded by your browser straight from Statens vegvesen. The Live Road Traffic layer also draws the agency’s travel times (about 200 monitored routes in and around the cities: actual against expected travel time and a traffic status, DATEX II 3.1 from the same service), through our server and cached for 90 seconds. Licence: Norwegian Licence for Open Government Data (NLOD) 2.0. Credit: Contains data under the Norwegian licence for Open Government data (NLOD) distributed by Statens vegvesen.

Transport for NSW publishes the cameras of its Live Traffic service (about 250, mostly in Sydney) as open data. The Australia page’s New South Wales Traffic Cameras layer lists them through our server (cached 30 minutes); the picture is loaded by your browser straight from Transport for NSW. Licence: Creative Commons Attribution 4.0. Credit: Camera pictures © Transport for NSW.

Entur, Norway’s national public transport agency, publishes the real-time positions of buses, trams, trains and ferries across the country (about 1,600 vehicles at a time) as open data. The Europe page’s Norway Live Public Transport layer asks for them through our server every 20 seconds at most (cached 15 seconds); Entur asks every client to identify itself, which our server does. Licence: Norwegian Licence for Open Government Data (NLOD) 2.0. Credit: Contains data under the Norwegian licence for Open Government data (NLOD) distributed by Entur.

NDW, the Dutch national road traffic data portal, publishes the speed measurements of its road sensors as open data (DATEX II files updated every minute). The Europe page’s Live Road Traffic layer reads the speed file through our server (about 8,000 places on the national and provincial roads, cached one minute) and places each reading with a site table cut from NDW’s own site file. The feed has no free-flow speed, so the layer’s colours use fixed speed bands per road class. NDW publishes the data for free reuse and declares CC0 for the content of its site; no credit is required, which this site gives anyway. NDW is replacing its DATEX II 2.3 files with version 3 files by February 2027; this layer already uses the version 3 files.

HSL (Helsinki Region Transport) publishes the real-time positions of its buses, trams, metro trains, commuter trains and ferries (about 650 vehicles at a time) as open data in the GTFS Realtime format; no key is needed. The Europe page’s Helsinki and Netherlands Live Public Transport layer asks for them through our server (cached 15 seconds), and takes line numbers and route names from HSL’s GTFS timetable file, of which our server reads only the small routes table with range requests. Licence: Creative Commons Attribution 4.0 (HSL licenses its open data sets and interfaces under it). Credit: © HSL.

Stichting OpenGeo’s OVapi service combines the open real-time data of the Dutch transit agencies into one GTFS Realtime feed (about 2,200 buses, trams, metro trains and ferries at a time) and publishes the matching timetable file. The Europe page’s Helsinki and Netherlands Live Public Transport layer asks for the positions through our server (cached 45 seconds) and reads line numbers and route names from the timetable file’s routes table. Terms: free to use, best effort with no service level agreement; clients must identify themselves (our server does) and must not claim to represent a transit agency. Credit: Dutch integrated real-time transit data, Stichting OpenGeo.

TransLink, the Queensland Government’s public transport authority, publishes the real-time positions of buses, trams, trains and ferries in South East Queensland (up to about 1,500 vehicles in the daytime) in the GTFS Realtime format, without authentication. The Australia page’s South East Queensland Live Public Transport layer asks for them through our server (cached 20 seconds) and reads route names from TransLink’s GTFS timetable file. Licence: Creative Commons Attribution 4.0. Credit: © State of Queensland (TransLink).

The leading free and open-source desktop GIS. Supports vector, raster, and database layers. Excellent plugin ecosystem. Available for Windows, Mac, Linux.

ESRI's professional desktop GIS. Industry standard for enterprise spatial analysis, cartography, and 3D visualization. Subscription-based.

Geographic Resources Analysis Support System. Powerful raster/vector analysis and remote sensing. Used by academic researchers and government agencies worldwide.

System for Automated Geoscientific Analyses. Excellent for terrain analysis, hydrology modeling, and environmental sciences.

Open-source GIS with strong cartographic capabilities. Popular in Latin America and Spain. Supports WMS, WFS, and PostGIS.

High-performance desktop GIS with GPU-accelerated processing. Unique parallelized engine for large datasets. One-time license.

Versatile GIS tool known for its file format support (300+), terrain analysis, and lidar processing. Popular with geologists and surveyors.

Full GIS, remote sensing, and image processing suite. Free TNTlite version available with dataset size limits.

Cloud-based GIS platform for hosting, analyzing, and sharing spatial data. The backbone of many government open data portals. Free public account available.

Modern collaborative web mapping platform. Drag-and-drop file upload, team editing, rich basemap options. Free for personal use.

Open-source browser-based large-scale geospatial data visualization tool. Excellent for point clouds, heatmaps, and 3D analysis.

Quick browser-based tool for creating, editing, and viewing GeoJSON, KML, and CSV geographic data.

Developer platform for custom maps and location services. Industry-leading style editor, vector tiles, and navigation APIs.

Cloud-based platform for planetary-scale geospatial analysis. Access to petabytes of satellite imagery and a JavaScript/Python API. Free for research.

Simple web platform for creating and sharing annotated maps. Supports GeoJSON, KML, GPX. Good for non-technical users.

WebGL-powered framework for large-scale data visualization on maps. Handles millions of data points in real time.

The HTML-native mapping framework used to build AeroPlanimetry. W3C Maps for HTML Community Group proposal. Leaflet-based under the hood.

The leading open-source JavaScript library for mobile-friendly interactive maps. Lightweight, extensible, and widely adopted. Powers MapML, and is also loaded directly (version 1.9.4) for the full-size Historical Documents viewer.

JavaScript library by Shashwat Kandadai and contributors that implements the SGP4/SDP4 orbit models used with NORAD two-line element sets. The Global page’s Space Stations layer loads it (version 5.0.0, from cdnjs, checked against a fixed integrity hash) the first time the layer is switched on, and your browser uses it with CelesTrak’s orbit data to work out where the International Space Station and Tiangong are every second. In testing the ISS position agreed with an independent live position to within about half a kilometre. MIT licence.

JavaScript library by Niklas von Hertzen that draws a web page, or part of it, onto a canvas so it can be saved as an image. AeroPlanimetry loads it (version 1.4.1, from cdnjs, checked against a fixed integrity hash) only when you press Save PNG or Print Map, and uses it in your browser to capture the map you are looking at. MIT licence.

JavaScript library by Stuart Knightley and contributors for reading and creating ZIP files in the browser. AeroPlanimetry loads it (version 3.10.1, from cdnjs, checked against a fixed integrity hash) only when you load a KMZ file (a zipped KML map file) from your computer, to open the archive and read the KML inside. The file stays on your computer. Dual-licensed MIT or GPLv3; used here under the MIT licence.

Full-featured JavaScript mapping library. Stronger than Leaflet for WMS/WFS, projections, and vector tile support.

Open-source fork of Mapbox GL JS. GPU-accelerated vector tile rendering in the browser. Supports 3D terrain and custom styles.

JavaScript library for 3D globes and maps in the browser. Supports 3D Tiles, KML, GeoJSON, and terrain. Used for visualizing satellite orbits and 3D city models.

Python library extending pandas for geospatial operations — reading shapefiles, spatial joins, projections, and plotting.

Python library for manipulation and analysis of planar geometric objects — intersection, union, buffer, and more.

Python library for reading and writing geospatial raster data. Works with GeoTIFF, NetCDF, and other formats using GDAL under the hood.

The universal translator for geospatial data formats. Supports 200+ raster and vector formats. Foundation of most GIS software.

Open Geospatial Consortium standard for serving georeferenced map images over the internet. Used for GetMap and GetFeatureInfo requests.

Standard for serving geographic features (vector data) in GML or GeoJSON. Used for querying individual feature attributes.

Standard for serving pre-rendered map tiles in a grid. Faster than WMS for display. Used by most modern basemap services.

JSON-based format for encoding geographic data structures. The de facto standard for web mapping APIs.

The HTML-native mapping format used by AeroPlanimetry. W3C Maps for HTML Community Group draft specification.

Searchable database of all EPSG coordinate reference systems. Essential for understanding projections and datums.

International Image Interoperability Framework standard for requesting regions and sizes of very large images by URL. The Library of Congress serves its map scans this way, which lets the Historical Documents viewer load only the tiles you are looking at instead of the whole file. Free specification.

ESRI offers many free courses on GIS fundamentals, ArcGIS, spatial analysis, and remote sensing. Good for beginners and professionals.

Comprehensive tutorials for QGIS covering everything from basic map creation to advanced spatial analysis and Python scripting.

Free and paid courses on QGIS, Google Earth Engine, Python for GIS, and spatial data science. High quality practical tutorials.

University of Helsinki open course on GIS automation using Python (GeoPandas, Shapely, Rasterio). Excellent for developers.

Essential documentation for the ArcGIS REST API — Identify, Query, and Export operations used extensively in AeroPlanimetry.

An open-source 3D globe that combines live feeds (aircraft, satellites, cameras, weather, traffic, public transport, radio and more). Its code is MIT-licensed, and its DATA_SOURCES.md catalogues about 60 feeds with each one’s own licence, noting which are not usable commercially. AeroPlanimetry uses none of its code; the catalogue guided the search for open live feeds (lightning, satellite mosaics, wildfire perimeters, traffic cameras, aircraft, space stations, launches, radio, transit and others), and every feed’s licence was then checked at the provider. The feeds from it that could not be used are on the Tested — Not Used cards: its bundled TeleGeography cables and Bhote Koshi flood pack are non-commercial, and OpenSky, Open-Meteo, Google, TomTom, adsbdb and OSRM are limited as described there.

US government open data portal. Thousands of geospatial datasets from federal agencies.

Search and download satellite imagery, aerial photography, digital elevation models, and more from USGS.

Public domain world vector and raster map data. Cultural, physical, and raster themes at 1:10m, 1:50m, and 1:110m scales.

Thousands of open datasets published by government and nonprofit organizations through ArcGIS Hub.

Open map data from Amazon, Meta, Microsoft, and TomTom. Buildings, places, transportation, and admins. Free to download and use.

Database of global administrative boundaries (country, province, district) in multiple formats. Free for non-commercial use.

Global ocean and land elevation data. High-quality bathymetric grid for the world's oceans. Freely downloadable.

Community platform for high-resolution topographic data — lidar point clouds, DEMs, and derived products.

A categorised directory of more than 500 links to freely available geographic datasets, organised by theme (elevation, hydrology, land cover, boundaries, population and more) and by country. Mostly download pages rather than map services. Some data is free for non-commercial use only and a few older links no longer work, so check each dataset's licence. See the site's FAQ for how the list is compiled.