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Short facts about QGIS and open geospatial, each checked against the source it links to. Link to any one of them to share it. Spotted something out of date? Let us know.

QGIS

  1. In QGIS version numbers, even numbers such as 4.2 are releases and odd numbers such as 4.1 are development versions.

    Link to this fact · Source: QGIS Roadmap (opens in a new tab) ↗ · Learn more: Introduction to QGIS

  2. A new QGIS release comes out every four months. Once a year a Long Term Release (LTR) enters the LTR repository and is maintained until the next LTR replaces it.

    Link to this fact · Source: QGIS Roadmap (opens in a new tab) ↗ · Learn more: Introduction to QGIS

  3. QGIS 3.0 brought a native 3D map view. It drapes your 2D map over terrain and can take heights from an elevation raster.

    Link to this fact · Source: Changelog for QGIS 3.0 (opens in a new tab) ↗ · Learn more: Beyond 2D and static maps

  4. The QGIS community has developed more than 2,000 plugins, free add-ons that extend what QGIS can do.

    Link to this fact · Source: QGIS overview (opens in a new tab) ↗ · Learn more: Introduction to QGIS

  5. QGIS 4.0 moved the core of QGIS onto the Qt6 framework, yet it was built to feel familiar to anyone who used earlier versions.

    Link to this fact · Source: Changelog for QGIS 4.0 (opens in a new tab) ↗

  6. You can run QGIS Processing tools without opening QGIS. The qgis_process command runs algorithms and models straight from the command line.

    Link to this fact · Source: QGIS User Guide: Using processing from the command line (opens in a new tab) ↗

  7. QGIS has been in development since 2002. It is built with C++ and the Qt toolkit, and its interface supports many languages.

    Link to this fact · Source: QGIS README (qgis/QGIS on GitHub) (opens in a new tab) ↗

  8. A .qgz project is a zip archive. Unzip it and you'll find the .qgs project file, which is XML, and a .qgd SQLite database holding auxiliary data.

    Link to this fact · Source: QGIS User Guide: QGIS projects (opens in a new tab) ↗ · Learn more: Introduction to QGIS

  9. QGIS used to be called Quantum GIS. With version 2.0 the project dropped the word Quantum, which it said never had any particular significance.

    Link to this fact · Source: Changelog for QGIS 2.0 (opens in a new tab) ↗ · Learn more: Introduction to QGIS

  10. QGIS releases are named after places, usually where QGIS developer meetings were held. With more releases than meetings, national QGIS user groups now suggest names too.

    Link to this fact · Source: QGIS release name from UK user group (OSGeo-UK mailing list, forwarding the QGIS PSC request) (opens in a new tab) ↗ · Learn more: Introduction to QGIS

Maps and geospatial data

  1. A degree of latitude covers about 111 km on the ground, and a single second of latitude only about 30.7 m.

    Link to this fact · Source: What is latitude? (NOAA National Ocean Service) (opens in a new tab) ↗ · Learn more: The prescribed map layout

  2. The EPSG in EPSG:4326 stands for European Petroleum Survey Group: energy companies that began pooling their coordinate system definitions in the mid-1980s. The name stuck.

    Link to this fact · Source: EPSG History (IOGP) (opens in a new tab) ↗ · Learn more: Gentle introduction to geospatial concepts

  3. A GeoPackage (.gpkg) is an SQLite database, so one file can hold vector features, raster tiles, and non-spatial tables together.

    Link to this fact · Source: GeoPackage (OGC) (opens in a new tab) ↗ · Learn more: Introduction to layers in QGIS

  4. In 1854, John Snow plotted cholera cases in Soho, London, on a map, which led him to a contaminated water pump. He convinced the authorities to remove its handle.

    Link to this fact · Source: John Snow: Cholera & the Broad Street pump (London Museum) (opens in a new tab) ↗

  5. On the Mercator projection Greenland looks bigger than South America, even though it is only one-eighth the size.

    Link to this fact · Source: Map Projections: A Working Manual (USGS Professional Paper 1395, John P. Snyder) (opens in a new tab) ↗ · Learn more: Gentle introduction to geospatial concepts

  6. Null Island, at 0° latitude and 0° longitude, is fictional. Natural Earth added it as a 1-meter-square island so geocoding failures sent to 0,0 are easy to flag.

    Link to this fact · Source: Natural Earth version 1.3 release notes (opens in a new tab) ↗

  7. PRS92, the datum that replaced Luzon 1911 in the Philippines, still uses the Clarke 1866 ellipsoid. EPSG also lists it under the alias Modified Luzon Datum.

    Link to this fact · Source: Philippine Reference System 1992 (EPSG datum 6683) (opens in a new tab) ↗ · Learn more: Laying the foundation

  8. PRS92 became the standard reference for all surveying and mapping in the Philippines through Executive Order No. 45 of 1993, partly to help solve overlapping boundaries and land disputes.

    Link to this fact · Source: Executive Order No. 280 (2000), amending Executive Order No. 45 (DENR) (opens in a new tab) ↗ · Learn more: Laying the foundation

  9. A shapefile is never just one file: it needs at least a .shp, .shx, and .dbf. Its field names max out at 10 characters, and each file is capped at 2 GB.

    Link to this fact · Source: GDAL: ESRI Shapefile / DBF driver (opens in a new tab) ↗ · Learn more: Gentle introduction to geospatial concepts

  10. Tobler's First Law of Geography: "Everything is related to everything else, but near things are more related than distant things." Waldo Tobler published it in 1970.

    Link to this fact · Source: Tobler's first law of geography (Wikipedia) (opens in a new tab) ↗ · Learn more: The why's and how's of learning geospatial

Open source and open data

  1. GDAL stands for Geospatial Data Abstraction Library. Frank Warmerdam started it in late 1998, and people still say it different ways: "goo-doll" or "gee-doll."

    Link to this fact · Source: GDAL FAQ (opens in a new tab) ↗

  2. Steve Coast founded OpenStreetMap in 2004. Its first contribution was a street he entered on December 10, 2004, after cycling around London's Regent's Park with a GPS receiver.

    Link to this fact · Source: History of OpenStreetMap (OpenStreetMap Wiki) (opens in a new tab) ↗

  3. OpenStreetMap data is open under the Open Database License (ODbL): you can copy, share, and adapt it as long as you credit OpenStreetMap and its contributors.

    Link to this fact · Source: OpenStreetMap copyright and license (opens in a new tab) ↗

  4. By January 1, 2014, 1,670 OpenStreetMap volunteers from 82 countries had mapped for the Typhoon Yolanda (Haiyan) response in the Philippines, mostly from home.

    Link to this fact · Source: Typhoon Haiyan (OpenStreetMap Wiki) (opens in a new tab) ↗