Sources

"Last checked" is the date someone confirmed the edition at the issuer. Where it says the edition comes from our research notes, the issuer's page has not been re-checked yet.

• 14 CFR Part 1 definitions

  Issuer: FAA (eCFR). Edition: eCFR.

  Last checked: 2026-09-18. Checked at the issuer on 2026-09-18. Night and flight-time definitions.

  Issuer page

  3 tools cite it

  • Block time (out to in)
  • Decimal hours to hours and minutes
  • The four aviation nights

• 14 CFR Part 107

  Issuer: FAA (eCFR). Edition: eCFR.

  Last checked: 2026-09-18. Checked at the issuer on 2026-09-18. Values in data/regulations.json.

  Issuer page

  5 tools cite it

  • Drone impact kinetic energy
  • Part 107 maximum altitude
  • Part 107 groundspeed check
  • Height for a target GSD
  • The four aviation nights

• 14 CFR Part 61

  Issuer: FAA (eCFR). Edition: eCFR.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  2 tools cite it

  • The four aviation nights
  • Night passenger currency

• 14 CFR Part 91

  Issuer: FAA (eCFR). Edition: eCFR.

  Last checked: 2026-09-22. Sections 91.151 and 91.167 checked at the issuer on 2026-09-22. Values in data/regulations.json.

  Issuer page

  3 tools cite it

  • Flight level and altitude
  • Fuel planning
  • The four aviation nights

• A soil-adjusted vegetation index (SAVI)

  Issuer: Huete, A. R., Remote Sensing of Environment. Edition: Volume 25, issue 3, pages 295-309.

  Last checked: 2026-09-22. Verified at the DOI registry on 2026-09-22: title, journal, volume, issue, pages, and year as cited.

  Issuer page

  1 tool cites it

  • SAVI

• A terrain ruggedness index that quantifies topographic heterogeneity

  Issuer: Riley, S. J., DeGloria, S. D., and Elliot, R., Intermountain Journal of Sciences. Edition: Volume 5, issues 1-4, pages 23-27.

  Last checked: 2026-09-22. Read the reprint PDF on 2026-09-22: Intermountain Journal of Sciences, Vol. 5, No. 1-4: 23-27, December 1999, by Riley, DeGloria, and Elliot. Its first page carries an erratum correcting the published code: TRI is the square root of the summed squared differences, not the squared sum. The journal is not indexed by DOI.

  Issuer page

  1 tool cites it

  • Terrain ruggedness and position

• AASHTO A Policy on Geometric Design of Highways and Streets (Green Book)

  Issuer: American Association of State Highway and Transportation Officials. Edition: 7th edition.

  Last checked: 2026-09-20. Checked at the AASHTO store on 2026-09-20: 7th edition, 2018. Cited for the design K tables, which are not reproduced: the vertical-curve tool takes K as an input.

  Issuer page

  1 tool cites it

  • Vertical curve

• AC 150/5340-1 Standards for Airport Markings

  Issuer: FAA. Edition: AC 150/5340-1M.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  2 tools cite it

  • Rank runways for the wind
  • Runway wind components

• Aeronautical Information Manual

  Issuer: FAA. Edition: current.

  Last checked: 2026-09-23. Checked at the issuer on 2026-09-23: the basic AIM with Changes 1, 2, and 3 (Change 3 dated July 9, 2026). Holding paragraph 5-3-8j: entry procedures FIG 5-3-4, maximum holding airspeeds TBL 5-3-24.

  Issuer page

  10 tools cite it

  • Cold temperature altitude correction
  • Holding pattern entry
  • Maximum holding airspeed
  • Holding wind correction and timing
  • Visual descent point
  • Rank runways for the wind
  • Wind triangle: course and groundspeed from a heading
  • Wind triangle: heading and groundspeed
  • Runway wind components
  • Wind triangle: airspeed and heading for a groundspeed

• Aircraft Weight and Balance Handbook

  Issuer: FAA. Edition: FAA-H-8083-1B.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  4 tools cite it

  • Ballast to move the CG
  • Fuel weight
  • Weight and balance
  • Weight shift

• Airplane Flying Handbook

  Issuer: FAA. Edition: FAA-H-8083-3C.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  3 tools cite it

  • Glide range with wind
  • Pivotal altitude
  • Turn performance and load factor

• Alduchov and Eskridge (1996) Magnus form

  Issuer: Journal of Applied Meteorology. Edition: Vol. 35, No. 4.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  1 tool cites it

  • Density altitude

• Altimeter Setting (WxCalc)

  Issuer: National Weather Service, El Paso. Edition: Web calculator documentation.

  Last checked: 2026-09-22. Formula read from the NWS PDF on 2026-09-22.

  Issuer page

  1 tool cites it

  • QNH, QFE, and QNE

• ASPRS Positional Accuracy Standards for Digital Geospatial Data

  Issuer: ASPRS. Edition: Edition 2.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  1 tool cites it

  • ASPRS accuracy (Edition 2)

• Astronomical Algorithms

  Issuer: Willmann-Bell. Edition: 2nd edition.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  1 tool cites it

  • Sunrise, sunset, and twilight

• Aviation Weather Handbook

  Issuer: FAA. Edition: FAA-H-8083-28B.

  Last checked: 2026-09-23. Checked at the issuer on 2026-09-23: FAA-H-8083-28B (page updated 2026-04-13) supersedes FAA-H-8083-28A (2024). Every cited part was compared against 28A: section 8.4, section 3.4.2.14 with tables 3-17 and 3-18, section 24.4 with table 24-3, and section 27.2 changed only in wording; 28B corrects the FB coding example to 750252, matching table 27-1; the TAF chapter moved from 27.3 to 27.4 with its examples unchanged.

  Issuer page

  8 tools cite it

  • Density altitude
  • Pressure altitude
  • Cloud base and freezing level
  • Winds aloft (FB) decoder
  • METAR decoder
  • TAF decoder
  • Winds aloft between levels
  • Wind components (u and v)

• Bing Maps Tile System

  Issuer: Microsoft. Edition: Online documentation.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  5 tools cite it

  • Map tile bounds
  • Map tiles covering a box
  • Map tile parent and children
  • Map tile for a point (XYZ, TMS, quadkey)
  • Map ground resolution and scale

• Brown's Boundary Control and Legal Principles

  Issuer: Wiley. Edition: 7th edition.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  3 tools cite it

  • Basis-of-bearing rotation
  • Deed parser (metes and bounds)
  • Deed plot, closure, and area

• Common Format and MIME Type for CSV Files (RFC 4180)

  Issuer: IETF. Edition: RFC 4180.

  Last checked: 2026-09-22. Checked at rfc-editor.org on 2026-09-22: RFC 4180, Informational, October 2005; updated by RFC 7111 (fragment identifiers only), not obsoleted.

  Issuer page

  1 tool cites it

  • Export a mission (KML, GeoJSON, CSV)

• Computing Discrete Fréchet Distance (Eiter and Mannila)

  Issuer: Technische Universität Wien, Christian Doppler Laboratory for Expert Systems. Edition: Technical Report CD-TR 94/64.

  Last checked: 2026-09-22. Checked on 2026-09-22 at the authors' archive: the PDF's title page reads CD-TR 94/64, April 25, 1994. A fixed technical report, not revised.

  Issuer page

  1 tool cites it

  • Compare two tracks

• de Berg et al. (2008) Computational Geometry: Algorithms and Applications

  Issuer: Springer. Edition: 3rd edition.

  Last checked: 2026-09-22. DOI resolved at Crossref on 2026-09-22 (Springer, 2008, the third edition); newer editions not yet checked at the publisher.

  Issuer page

  2 tools cite it

  • Delaunay triangulation of points
  • Voronoi cells around points

• Department of Defense World Geodetic System 1984

  Issuer: NGA. Edition: NGA.STND.0036_1.0.0_WGS84.

  Last checked: 2026-09-19. Checked at the issuer on 2026-09-19: the NGA download serves NGA.STND.0036_1.0.0_WGS84.pdf.

  Issuer page

  4 tools cite it

  • Transform between ITRF and WGS 84 realizations
  • Ellipsoid parameters
  • ECEF to latitude, longitude, and height
  • Latitude, longitude, and height to ECEF

• Deprecation of the U.S. survey foot

  Issuer: NIST, NOAA. Edition: 85 FR.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  14 tools cite it

  • Length converter
  • Feet to meters
  • US survey feet to international feet
  • US survey feet to meters
  • Inches to millimeters
  • Kilometers to miles
  • Kilometers to nautical miles
  • Meters to feet
  • Meters to US survey feet
  • Miles to kilometers
  • Statute miles to nautical miles
  • Millimeters to inches
  • Nautical miles to kilometers
  • Nautical miles to statute miles

• Development of a two-band enhanced vegetation index without a blue band

  Issuer: Jiang, Z., Huete, A. R., Didan, K., and Miura, T., Remote Sensing of Environment. Edition: Volume 112, issue 10, pages 3833-3845.

  Last checked: 2026-09-22. Verified at the DOI registry on 2026-09-22: title, journal, volume, issue, pages, and year as cited.

  Issuer page

  1 tool cites it

  • EVI2

• Douglas and Peucker (1973) line reduction

  Issuer: Cartographica. Edition: Vol. 10, No. 2.

  Last checked: 2026-09-22. DOI resolved at doi.org on 2026-09-22; a journal article, so its edition does not change.

  Issuer page

  1 tool cites it

  • Simplify a line or polygon (Douglas-Peucker)

• EASA Guidelines for UAS operations in the open and specific category

  Issuer: EASA. Edition: Issue 03, 17 July 2025.

  Last checked: 2026-09-23. Checked at the issuer on 2026-09-23: the download is Issue 03 of 17 July 2025, with the VLOS procedure (ALOS 327 x CD + 20 m, 490 x CD + 30 m; DLOS 0.3 x GV, where the ground visibility "minimum value should be at least 5 km") unchanged. Its footnote points to the LBA guidance (ledger row lba-flight-geography), which caps GV at 5 km and whose section 7.1 table is used as the worked example.

  Issuer page

  1 tool cites it

  • Visual line of sight distance

• EGM96 geopotential model and geoid

  Issuer: NASA GSFC and NIMA (NGA). Edition: NASA/TP-1998-206861.

  Last checked: 2026-09-18. Checked at the issuer on 2026-09-18. Grid from GeographicLib egm96-15 (2009-08-29).

  Issuer page

  2 tools cite it

  • Geoid height (EGM96)
  • Ellipsoidal and orthometric height

• Elementary Surveying: An Introduction to Geomatics

  Issuer: Pearson. Edition: 16th edition.

  Last checked: 2026-09-23. Checked on 2026-09-23 against Pearson's catalog page: the 16th edition (2021, print ISBN 9780136822806) is current. Its chapters 4, 5, 6, 10, 11, 12, 24, 25, and 26, the ones the tools cite, keep the 15th edition's numbers and subjects.

  Issuer page

  34 tools cite it

  • Angular closure of a loop traverse
  • Area by coordinates (acreage)
  • Coordinates from a bearing and distance
  • Intersection (bearings and distances)
  • Inverse between two coordinates
  • Least-squares network adjustment (2D)
  • Total-station offset shot
  • Three-point resection
  • Station and offset from a line
  • Traverse closure and adjustment
  • Horizontal circular curve
  • Circular curve layout table
  • Vertical curve length for sight distance
  • Spiral-curve-spiral transition
  • Unequal-tangent vertical curve
  • Vertical curve
  • Average end area volume
  • Grid (borrow-pit) volume
  • Side slope and grade (H:V)
  • Prismoidal volume
  • Profile grade analysis
  • Cross-section cut and fill areas
  • Swell, shrink, and truck loads
  • Slope stake (catch point)
  • Cone, frustum, and prism volumes
  • Stockpile volume (TIN)
  • Site localization (calibration)
  • Basis-of-bearing rotation
  • Deed plot, closure, and area
  • Curvature and refraction correction
  • Height of an inaccessible object
  • Level run reduction and closure
  • Slope distance to horizontal and vertical
  • Stadia reduction

• Elements of Photogrammetry with Applications in GIS

  Issuer: McGraw-Hill. Edition: 4th edition.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  10 tools cite it

  • Corridor mapping lines
  • Facade scan
  • Survey grid (lawnmower pattern)
  • Height for a target GSD
  • Ground sampling distance (GSD)
  • Image count and survey size
  • Motion blur and slowest shutter
  • Oblique GSD and footprint
  • Overlap over high terrain
  • Overlap, trigger interval, and line spacing

• EPSG Geodetic Parameter Dataset

  Issuer: IOGP. Edition: v10.094, as shipped in PROJ 9.3.0.

  Last checked: 2026-09-19. Checked on 2026-09-19: proj.db in PROJ 9.3.0 (pyproj 3.6.1) reports EPSG v10.094; used for the SPCS83 zones and the legacy-datum transformations.

  Issuer page

  1 tool cites it

  • Legacy datum to or from WGS 84

• Espenak and Meeus Delta T polynomials

  Issuer: NASA GSFC. Edition: Five Millennium Canon.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  1 tool cites it

  • Sun position (azimuth and elevation)

• FAA Order JO 7900.5 Surface Weather Observing

  Issuer: FAA. Edition: JO 7900.5E.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  2 tools cite it

  • METAR decoder
  • TAF decoder

• Geodetic Reference System 1980

  Issuer: IAG. Edition: Journal of Geodesy 74(1).

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  4 tools cite it

  • Ellipsoid parameters
  • Haversine distance (spherical)
  • Great-circle destination (spherical)
  • Great-circle distance and course (spherical)

• GEOG 892: Geospatial Applications of Unmanned Aerial Systems

  Issuer: Abdullah, Q., Penn State College of Earth and Mineral Sciences. Edition: online course text.

  Last checked: 2026-09-23. Read at courses.ems.psu.edu on 2026-09-23: Lesson 4, Designing a Flight Route. Number of flight lines = width / spacing + 1, rounded up, the first line on the southern boundary; images per line = length / air base + 1, rounded up, plus two at each end (10 lines, 43 images per line, 430 images). An online course text with no numbered editions.

  Issuer page

  2 tools cite it

  • Survey grid (lawnmower pattern)
  • Image count and survey size

• GeographicLib

  Issuer: C. F. F. Karney. Edition: GeographicLib 2.x.

  Last checked: 2026-09-18. Checked at the issuer on 2026-09-18. GeographicLib 2.7 installed for GeoidEval parity.

  Issuer page

  22 tools cite it

  • Radii of curvature and degree lengths
  • ECEF to latitude, longitude, and height
  • Local ENU, NED, or AER to point
  • Latitude, longitude, and height to ECEF
  • Point to local ENU, NED, and AER
  • Geoid height (EGM96)
  • Latitude and longitude to GARS
  • GARS to latitude and longitude
  • Latitude and longitude to GEOREF
  • GEOREF to latitude and longitude
  • Latitude and longitude to MGRS
  • MGRS to latitude and longitude
  • Ellipsoidal and orthometric height
  • Polygon area and perimeter on the ellipsoid
  • Destination from a start, course, and distance (geodesic)
  • Distance between two points (geodesic)
  • Destination on a constant course (rhumb line)
  • Rhumb line distance and course
  • 3D distance between two points
  • Look angles to a target
  • Vector sum, dot, and cross product
  • Vector components and direction

• Geohash

  Issuer: G. Niemeyer. Edition: Original description.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  5 tools cite it

  • One place in every index, at a matched cell size
  • Geohashes covering an area
  • Geohash decoder
  • Geohash encoder
  • Geohash neighbors

• Global Area Reference System

  Issuer: NGA. Edition: NGA GARS web description.

  Last checked: 2026-09-19. Checked at the issuer on 2026-09-19: the NGA coordinate systems page describes GARS.

  Issuer page

  2 tools cite it

  • Latitude and longitude to GARS
  • GARS to latitude and longitude

• GPS Antenna Calibration: antenna reference point and slant heights

  Issuer: NOAA National Geodetic Survey. Edition: ANTINFO and antenna calibration pages.

  Last checked: 2026-09-22. The page answered on 2026-09-22; antenna radii and ARP offsets come from its ANTINFO records.

  Issuer page

  1 tool cites it

  • Antenna height from a slant measurement

• Gracey, NASA RP-1046

  Issuer: NASA. Edition: NASA RP-1046.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  3 tools cite it

  • True airspeed from indicated or calibrated airspeed
  • Calibrated airspeed from true airspeed or Mach
  • Total and static air temperature

• H3 hexagonal index

  Issuer: Uber and H3 contributors. Edition: H3 4.x.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  16 tools cite it

  • One place in every index, at a matched cell size
  • H3 cell inspector
  • H3 local IJ for a cell (cellToLocalIj)
  • H3 cell set outline (cellsToMultiPolygon)
  • H3 children cells
  • H3 compact
  • H3 edges and vertexes
  • H3 grid disk (k-ring)
  • H3 grid path and distance
  • H3 grid ring
  • H3 cell for a point
  • H3 cell at local IJ (localIjToCell)
  • H3 parent cell
  • H3 polygon fill (polygonToCells)
  • H3 resolution chooser
  • H3 uncompact

• h3o (Rust H3)

  Issuer: Hydronium Labs. Edition: 0.11.0.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  15 tools cite it

  • H3 cell inspector
  • H3 local IJ for a cell (cellToLocalIj)
  • H3 cell set outline (cellsToMultiPolygon)
  • H3 children cells
  • H3 compact
  • H3 edges and vertexes
  • H3 grid disk (k-ring)
  • H3 grid path and distance
  • H3 grid ring
  • H3 cell for a point
  • H3 cell at local IJ (localIjToCell)
  • H3 parent cell
  • H3 polygon fill (polygonToCells)
  • H3 resolution chooser
  • H3 uncompact

• Hill shading and the reflectance map

  Issuer: Horn, B. K. P., Proceedings of the IEEE. Edition: Volume 69, issue 1, pages 14-47.

  Last checked: 2026-09-22. Verified at the DOI registry on 2026-09-22: title, journal, volume, issue, pages, and year as cited.

  Issuer page

  1 tool cites it

  • Slope, aspect, and hillshade

• Horizontal Time-Dependent Positioning (HTDP)

  Issuer: NGS. Edition: HTDP 3.6.0 (2025-04-07).

  Last checked: 2026-09-19. Checked at the issuer on 2026-09-19: HTDP-download.zip holds version 3.6.0 (April 7, 2025); compiled and run to generate the vectors.

  Issuer page

  1 tool cites it

  • Transform between NAD 83 and ITRF or WGS 84

• How do I use a scale factor with Landsat Level-2 science products?

  Issuer: United States Geological Survey. Edition: USGS FAQ, read 2026-09-22.

  Last checked: 2026-09-22. Read at the USGS on 2026-09-22: Collection 2 surface reflectance scale factor 0.0000275 with an additive offset of -0.2, valid range 7,273 to 43,636, fill value 0, and the worked example giving 0.313 from 18,639. A living FAQ page rather than an edition.

  Issuer page

  1 tool cites it

  • Digital number to reflectance

• How Far Can You Measure with a Thermal Camera?

  Issuer: Teledyne FLIR. Edition: Web article (2023-09-12).

  Last checked: 2026-09-22. Read on 2026-09-22: at least 3 x 3 pixels on a target for an accurate temperature measurement.

  Issuer page

  1 tool cites it

  • Thermal pixel footprint

• IANA Time Zone Database

  Issuer: IANA. Edition: 2026d.

  Last checked: 2026-09-18. Checked at the issuer on 2026-09-18. Release 2026d embedded.

  Issuer page

  2 tools cite it

  • Local time to UTC (Zulu)
  • Time zone rules at a date

• IARU Region 1 VHF Managers Handbook

  Issuer: IARU Region 1. Edition: IARU Region 1 VHF Managers Handbook, version 10.03.

  Last checked: 2026-09-19. Checked at the issuer on 2026-09-19: the handbooks page links VHF_Handbook_V10_03_final.pdf (February 2026).

  Issuer page

  2 tools cite it

  • Latitude and longitude to Maidenhead locator
  • Maidenhead locator to latitude and longitude

• ICAO Annex 5 Units of Measurement

  Issuer: ICAO. Edition: 5th edition.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  14 tools cite it

  • Pressure converter
  • HPa to inHg
  • InHg to hPa
  • KPa to psi
  • Psi to kPa
  • Speed converter
  • Km/h to knots
  • Knots to km/h
  • Knots to mph
  • Knots to m/s
  • Mph to knots
  • M/s to knots
  • Vertical speed converter
  • Ft/min to m/s

• ICAO Doc 8168 PANS-OPS

  Issuer: ICAO. Edition: Doc 8168.

  Last checked: not yet. Sold by ICAO, not read at the issuer. The Volume I holding-entry wording (entry by heading, a 5-degree zone of flexibility on the sector boundaries) was checked on 2026-09-23 in Transport Canada AIM RAC 10.5, which adopts it.

  Issuer page

  3 tools cite it

  • Cold temperature altitude correction
  • True altitude
  • Holding pattern entry

• IEEE Standard for Floating-Point Arithmetic (IEEE 754)

  Issuer: Institute of Electrical and Electronics Engineers. Edition: IEEE 754-2019.

  Last checked: 2026-09-22. Checked at the IEEE standards page on 2026-09-22: 754-2019 is the current edition, superseding 754-2008.

  Issuer page

  1 tool cites it

  • Band math

• IERS Bulletin C (leap seconds)

  Issuer: IERS. Edition: Bulletin C 72. Valid through: 2027-06-30.

  Last checked: 2026-09-18. Checked at the issuer on 2026-09-18. Bulletin C 72: no leap second through 2027-06-30.

  Issuer page

  2 tools cite it

  • GPS week and seconds to UTC
  • UTC to GPS week and seconds

• Improved Magnus Form Approximation of Saturation Vapor Pressure

  Issuer: Alduchov and Eskridge, Journal of Applied Meteorology. Edition: Vol. 35, No. 4 (1996).

  Last checked: 2026-09-22. A journal paper; the coefficients 6.1094 hPa, 17.625, and 243.04 °C are its AERK set.

  Issuer page

  1 tool cites it

  • Humidity and moist air

• Instrument Flying Handbook

  Issuer: FAA. Edition: FAA-H-8083-15B.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  8 tools cite it

  • DME arc lead points
  • DME slant range to ground distance
  • Holding pattern entry
  • Holding wind correction and timing
  • Fix from a radial and distance
  • Heading to intercept a radial
  • Time and distance to a station
  • Fly-by turn anticipation

• Instrument Procedures Handbook

  Issuer: FAA. Edition: FAA-H-8083-16B.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  3 tools cite it

  • Climb gradient and vertical speed
  • Top of descent
  • Visual descent point

• International Geomagnetic Reference Field

  Issuer: IAGA V-MOD. Edition: IGRF-14. Valid through: 2029-12-31.

  Last checked: 2026-09-18. Checked at the issuer on 2026-09-18. igrf14coeffs.txt from NOAA NGDC.

  Issuer page

  3 tools cite it

  • Magnetic declination
  • Grid variation (grivation)
  • True and magnetic bearings

• IOGP Guidance Note 7-2: Coordinate Conversions and Transformations

  Issuer: IOGP. Edition: Revised September 2019.

  Last checked: 2026-09-19. Checked at the issuer on 2026-09-19: iogp.org serves 373-07-02.pdf, Revised September 2019.

  Issuer page

  5 tools cite it

  • Helmert transformation (7 or 14 parameters)
  • Legacy datum to or from WGS 84
  • Arc-to-chord correction (t − T)
  • Latitude and longitude to state plane (SPCS83)
  • State plane (SPCS83) to latitude and longitude

• IS-GPS-200 GPS interface specification

  Issuer: U.S. Space Force. Edition: IS-GPS-200N.

  Last checked: 2026-09-23. Checked at the issuer on 2026-09-23: IS-GPS-200N is the current revision, amended by IRN-IS-200N-003 and IRN-IS-200N-004 (2026-06-16). The IRNs were not reviewed against the cited sections.

  Issuer page

  2 tools cite it

  • GPS week and seconds to UTC
  • UTC to GPS week and seconds

• ISO 6709 Geographic point location

  Issuer: ISO. Edition: ISO 6709:2022.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  4 tools cite it

  • Add and subtract DMS angles
  • Difference between two bearings
  • Read any coordinate
  • Format a coordinate

• ITRF2020 Plate Motion Model

  Issuer: Altamimi et al. (AGU, Geophysical Research Letters). Edition: e2023GL106373.

  Last checked: 2026-09-19. Checked on 2026-09-19: the DOI redirects to the AGU article at Wiley (which refuses scripted requests); rates match PROJ data/ITRF2020 (from IGN ITRF2020-PMM.dat).

  Issuer page

  1 tool cites it

  • Move a position between epochs (ITRF2020 plate motion)

• ITRF2020 transformation parameters to past ITRFs

  Issuer: IERS ITRF Center (IGN). Edition: Transfo-ITRF2020_TRFs.txt.

  Last checked: 2026-09-19. Checked at the issuer on 2026-09-19: itrf.ign.fr serves Transfo-ITRF2020_TRFs.txt; values match PROJ data/ITRF2020.

  Issuer page

  1 tool cites it

  • Transform between ITRF and WGS 84 realizations

• ITU-R P.530, terrestrial line-of-sight propagation

  Issuer: International Telecommunication Union. Edition: P.530-19 (09/2025).

  Last checked: 2026-09-19. Checked at the issuer on 2026-09-19: P.530-19 (09/2025) is in force.

  Issuer page

  1 tool cites it

  • Fresnel zone and radio link clearance

• Karney (2011) Transverse Mercator

  Issuer: Journal of Geodesy. Edition: Vol. 85, No. 8.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  6 tools cite it

  • Auxiliary latitudes
  • Arc-to-chord correction (t − T)
  • Latitude and longitude to state plane (SPCS83)
  • State plane (SPCS83) to latitude and longitude
  • Latitude and longitude to UTM
  • UTM to latitude and longitude

• Karney (2013) Algorithms for geodesics

  Issuer: Journal of Geodesy. Edition: Vol. 87, No. 1.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  33 tools cite it

  • Facade scan
  • Geofence around an area
  • Orbit around a point of interest
  • Survey grid (lawnmower pattern)
  • Polygon area and perimeter on the ellipsoid
  • Buffer a point, line, or polygon
  • Overlap, union, or difference of two polygons
  • Point in polygon
  • Bounding box, antimeridian-aware
  • Add vertices along geodesic edges (densify)
  • Hull, bounding rectangle, and enclosing circle
  • Destination from a start, course, and distance (geodesic)
  • Haversine distance (spherical)
  • Point part way along a great circle
  • Where two geodesic segments cross
  • Distance between two points (geodesic)
  • Midpoint on the geodesic
  • Great-circle destination (spherical)
  • Great-circle distance and course (spherical)
  • Highest point of a geodesic (vertex)
  • Vincenty direct (legacy)
  • Vincenty inverse (legacy)
  • Waypoints along a route line
  • Rhumb line distance and course
  • Closest point on a route
  • Where two courses cross
  • Closest point of approach
  • Cross-track and along-track distance
  • Fly-by turn anticipation
  • Intercept a moving target
  • Route legs, courses, and totals
  • Range rings
  • Time, speed, and distance

• Karney (2024) Geodesic intersections

  Issuer: Journal of Surveying Engineering. Edition: Vol. 150, No. 3.

  Last checked: 2026-09-22. DOI resolved and bibliographic data read from Crossref on 2026-09-22; a journal article, so its edition does not change.

  Issuer page

  1 tool cites it

  • Where two geodesic segments cross

• Karney (2024) The area of rhumb polygons

  Issuer: Studia Geophysica et Geodaetica. Edition: Vol. 68, No. 3-4.

  Last checked: 2026-09-22. DOI resolved and bibliographic data read from Crossref on 2026-09-22; a journal article, so its edition does not change.

  Issuer page

  1 tool cites it

  • Polygon area and perimeter on the ellipsoid

• Landscape Assessment (LA): sampling and analysis methods, in FIREMON: Fire Effects Monitoring and Inventory System

  Issuer: Key, C. H., and Benson, N. C., USDA Forest Service, Rocky Mountain Research Station. Edition: General Technical Report RMRS-GTR-164-CD, pages LA-1 to LA-55.

  Last checked: 2026-09-22. Verified at USDA Forest Service Treesearch on 2026-09-22: RMRS-GTR-164-CD, 2006. The report is a fixed technical report with no later edition.

  Issuer page

  2 tools cite it

  • dNBR (burn severity)
  • NBR

• LAS Specification 1.4 R15

  Issuer: ASPRS. Edition: 1.4 R15 (2019-07-09).

  Last checked: 2026-09-22. Minimum point data record sizes for formats 0 to 10 and the 375-byte header read in R15 on 2026-09-22; ASPRS allows unlimited distribution with attribution, and asprs.org's own copy was not reachable.

  Issuer page

  1 tool cites it

  • Dataset size estimate

• LBA Guidance for Dimensioning of Flight Geography, Contingency Volume and Ground Risk Buffer

  Issuer: Luftfahrt-Bundesamt. Edition: Revision 1.7, 26 November 2024.

  Last checked: 2026-09-23. Checked at the issuer on 2026-09-23: the English PDF linked from the EASA guidelines' VLOS footnote is revision 1.7 of 26 November 2024. Section 7 sets DLOS = 0.3 x GV with GVmax = 5 km; the section 7.1 table is valid for 5 km or more.

  Issuer page

  1 tool cites it

  • Visual line of sight distance

• Lidar Base Specification

  Issuer: U.S. Geological Survey, 3D Elevation Program. Edition: 2025 rev. A (June 2025).

  Last checked: 2026-09-22. Table 1 (aggregate nominal pulse spacing and density by quality level) read at the issuer on 2026-09-22.

  Issuer page

  1 tool cites it

  • Lidar mission planning

• Manual of Surveying Instructions (BLM)

  Issuer: Bureau of Land Management. Edition: 2009 Manual.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  3 tools cite it

  • Deed parser (metes and bounds)
  • Legacy land units
  • PLSS legal description reader

• Manual of the ICAO Standard Atmosphere (Doc 7488)

  Issuer: ICAO. Edition: 3rd edition.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  10 tools cite it

  • True airspeed from indicated or calibrated airspeed
  • Calibrated airspeed from true airspeed or Mach
  • Density altitude
  • Flight level and altitude
  • ISA temperature and deviation
  • Pressure altitude
  • QNH, QFE, and QNE
  • Humidity and moist air
  • Standard atmosphere
  • Multirotor hover power

• Map Projections: A Working Manual

  Issuer: USGS. Edition: Professional Paper 1395.

  Last checked: 2026-09-19. Checked at the issuer on 2026-09-19: USGS Publications Warehouse lists Professional Paper 1395.

  Issuer page

  4 tools cite it

  • Auxiliary latitudes
  • Ellipsoid parameters
  • Radii of curvature and degree lengths
  • Polygon centroid and interior point

• Minimum Standard Detail Requirements for ALTA/NSPS Land Title Surveys

  Issuer: ALTA and NSPS. Edition: 2026 standards, effective February 23, 2026.

  Last checked: 2026-09-22. Sections 3.E.i and 3.E.v read in the official PDF (v. 11.13.2025) on 2026-09-22. Values in data/regulations.json.

  Issuer page

  1 tool cites it

  • ALTA/NSPS relative positional precision

• Modification of normalised difference water index (NDWI) to enhance open water features in remotely sensed imagery

  Issuer: Xu, H., International Journal of Remote Sensing. Edition: Volume 27, issue 14, pages 3025-3033.

  Last checked: 2026-09-22. Verified at the DOI registry on 2026-09-22: title, journal, volume, issue, pages, and year as cited.

  Issuer page

  1 tool cites it

  • MNDWI

• Monitoring vegetation systems in the Great Plains with ERTS

  Issuer: Rouse, J. W., Haas, R. H., Schell, J. A., and Deering, D. W., NASA. Edition: Third ERTS Symposium, NASA SP-351, volume 1, pages 309-317.

  Last checked: 2026-09-22. Verified at NASA NTRS on 2026-09-22: record 19740022614, 1974, Rouse, Haas, Schell, Deering. A conference paper: it has no later edition.

  Issuer page

  1 tool cites it

  • NDVI

• Multiscale terrain analysis of multibeam bathymetry data for habitat mapping on the continental slope

  Issuer: Wilson, M. F. J., O'Connell, B., Brown, C., Guinan, J. C., and Grehan, A. J., Marine Geodesy. Edition: Volume 30, issues 1-2, pages 3-35.

  Last checked: 2026-09-22. Verified at the DOI registry on 2026-09-22: title, journal, volume, issue, pages, and year as cited.

  Issuer page

  1 tool cites it

  • Terrain ruggedness and position

• NADCON5 datum transformations

  Issuer: NOAA NGS. Edition: NOAA TR NOS NGS 63 (revised August 31, 2020); grids release 20160901.

  Last checked: 2026-09-23. Checked at the issuer on 2026-09-23: the NADCON 5.0 report is NOAA Technical Report NOS NGS 63 (Smith and Bilich, 2017, revised August 31, 2020), served by geodesy.noaa.gov as NOAA_TR_NOS_NGS_0063.pdf. The biquadratic interpolation it applies is documented separately in NOAA TM NOS NGS 84 (its own row).

  Issuer page

  1 tool cites it

  • Old US datums to NAD 83 (NADCON5)

• NDWI - A normalized difference water index for remote sensing of vegetation liquid water from space

  Issuer: Gao, B.-C., Remote Sensing of Environment. Edition: Volume 58, issue 3, pages 257-266.

  Last checked: 2026-09-22. Verified at the DOI registry on 2026-09-22: title, journal, volume, issue, pages, and year as cited.

  Issuer page

  1 tool cites it

  • NDWI (Gao, vegetation water)

• NGA.SIG.0012 UTM and UPS

  Issuer: NGA. Edition: NGA.SIG.0012_2.0.0_UTMUPS.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  6 tools cite it

  • Grid variation (grivation)
  • Latitude and longitude to UPS
  • UPS to latitude and longitude
  • Latitude and longitude to UTM
  • UTM to latitude and longitude
  • UTM zone and band lookup

• NGA.STND.0037 MGRS

  Issuer: NGA. Edition: NGA.STND.0037_2.0.0_GRIDS.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  3 tools cite it

  • Latitude and longitude to MGRS
  • MGRS to latitude and longitude
  • Read any coordinate

• NGS biquadratic interpolation

  Issuer: NOAA NGS. Edition: NOAA TM NOS NGS 84 (January 25, 2022).

  Last checked: 2026-09-23. Checked at the issuer on 2026-09-23: NOAA_TM_NOS_NGS_0084.pdf on geodesy.noaa.gov is Dru Smith's Biquadratic Interpolation, released September 2, 2020 and revised January 25, 2022.

  Issuer page

  1 tool cites it

  • Old US datums to NAD 83 (NADCON5)

• NIST Handbook 44

  Issuer: NIST. Edition: 2026 edition.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  24 tools cite it

  • Acres to hectares
  • Area converter
  • Square feet to acres
  • Hectares to acres
  • Length converter
  • Feet to meters
  • US survey feet to international feet
  • US survey feet to meters
  • Inches to millimeters
  • Kilometers to miles
  • Kilometers to nautical miles
  • Meters to feet
  • Meters to US survey feet
  • Miles to kilometers
  • Statute miles to nautical miles
  • Millimeters to inches
  • Nautical miles to kilometers
  • Nautical miles to statute miles
  • Mass converter
  • Kilograms to pounds
  • Pounds to kilograms
  • Volume converter
  • US gallons to liters
  • Liters to US gallons

• NIST SP 811 Guide for the Use of the SI

  Issuer: NIST. Edition: 2008 edition.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  57 tools cite it

  • Acceleration converter
  • Angle converter
  • Degrees to radians
  • Radians to degrees
  • Angular rate converter
  • Acres to hectares
  • Area converter
  • Square feet to acres
  • Hectares to acres
  • Battery charge converter
  • Data rate converter
  • Density converter
  • Energy converter
  • Frequency converter
  • Fuel volume and weight
  • Length converter
  • Feet to meters
  • US survey feet to international feet
  • US survey feet to meters
  • Inches to millimeters
  • Kilometers to miles
  • Kilometers to nautical miles
  • Meters to feet
  • Meters to US survey feet
  • Miles to kilometers
  • Statute miles to nautical miles
  • Millimeters to inches
  • Nautical miles to kilometers
  • Nautical miles to statute miles
  • Mass converter
  • Kilograms to pounds
  • Pounds to kilograms
  • Power converter
  • Pressure converter
  • HPa to inHg
  • InHg to hPa
  • KPa to psi
  • Psi to kPa
  • Normalize a unit-tagged value
  • Slope and grade converter
  • Speed converter
  • Km/h to knots
  • Knots to km/h
  • Knots to mph
  • Knots to m/s
  • Mph to knots
  • M/s to knots
  • Temperature difference converter
  • Celsius to Fahrenheit
  • Temperature converter
  • Fahrenheit to Celsius
  • Time converter
  • Vertical speed converter
  • Ft/min to m/s
  • Volume converter
  • US gallons to liters
  • Liters to US gallons

• NOAA Solar Calculator

  Issuer: NOAA GML. Edition: Spreadsheet and equations.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  3 tools cite it

  • Sunrise, sunset, and twilight
  • Mapping light window
  • Sun position (azimuth and elevation)

• Notices to Air Missions (NOTAM), FAA Order JO 7930.2

  Issuer: FAA. Edition: JO 7930.2U.

  Last checked: 2026-09-22. Edition and effective date read at the issuer on 2026-09-22.

  Issuer page

  1 tool cites it

  • TFR and NOTAM area

• NREL Solar Position Algorithm

  Issuer: NREL. Edition: NREL/TP-560-34302.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  4 tools cite it

  • Sunrise, sunset, and twilight
  • Sun hotspot in a camera frame
  • Mapping light window
  • Sun position (azimuth and elevation)

• OGC KML 2.3

  Issuer: Open Geospatial Consortium. Edition: OGC 12-007r2.

  Last checked: 2026-09-22. Checked at docs.ogc.org on 2026-09-22: OGC 12-007r2, KML version 2.3, dated 2015-08-04; section 9.20 defines altitudeMode, with absolute relative to sea level.

  Issuer page

  1 tool cites it

  • Export a mission (KML, GeoJSON, CSV)

• OGC Simple Feature Access, Part 1: Common Architecture

  Issuer: Open Geospatial Consortium. Edition: OGC 06-103r4, version 1.2.1.

  Last checked: 2026-09-22. Checked at ogc.org/standards/sfa on 2026-09-22: version 1.2.1 (06-103r4) is the current Implementation Standard; 1.2.0 and 1.1.0 are superseded.

  Issuer page

  1 tool cites it

  • Check and repair a polygon

• Open Location Code

  Issuer: Google. Edition: Specification in the project repository.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  4 tools cite it

  • One place in every index, at a matched cell size
  • Plus Code decoder
  • Plus Code encoder
  • Shorten a Plus Code

• OPUS: Online Positioning User Service, About

  Issuer: NOAA National Geodetic Survey. Edition: Web page, last modified 2026-09-09.

  Last checked: 2026-09-22. Data requirements read on 2026-09-22; the page had changed from the spec's OPUS-S and OPUS-RS windows, which the tool follows the page on.

  Issuer page

  1 tool cites it

  • OPUS session planning

• Overview of the radiometric and biophysical performance of the MODIS vegetation indices

  Issuer: Huete, A., Didan, K., Miura, T., Rodriguez, E. P., Gao, X., and Ferreira, L. G., Remote Sensing of Environment. Edition: Volume 83, issues 1-2, pages 195-213.

  Last checked: 2026-09-22. Verified at the DOI registry on 2026-09-22: title, journal, volume, issue, pages, and year as cited.

  Issuer page

  1 tool cites it

  • EVI

• PB2002 plate boundary model

  Issuer: P. Bird (AGU, G3). Edition: PB2002, 1027 (orogens as GeoJSON by Ahlenius, ODC-BY 1.0).

  Last checked: 2026-09-19. Checked on 2026-09-19: the DOI redirects to the AGU article at Wiley (which refuses scripted requests); the original FTP host is gone, so the orogens come from the fraxen/tectonicplates GeoJSON mirror (ODC-BY 1.0).

  Issuer page

  1 tool cites it

  • Move a position between epochs (ITRF2020 plate motion)

• Pilot's Handbook of Aeronautical Knowledge

  Issuer: FAA. Edition: FAA-H-8083-25C.

  Last checked: 2026-09-19. Checked at the issuer on 2026-09-19: the handbook page links faa-h-8083-25c.pdf. Worked examples for pressure altitude, density altitude, runway wind components, and the wind triangle taken from it.

  Issuer page

  22 tools cite it

  • True airspeed from indicated or calibrated airspeed
  • Density altitude
  • ISA temperature and deviation
  • Pressure altitude
  • True altitude
  • Holding wind correction and timing
  • Fuel planning
  • Performance table lookup
  • Glide range with wind
  • Specific range
  • Top of descent
  • Turn performance and load factor
  • Rank runways for the wind
  • Wind triangle: course and groundspeed from a heading
  • Wind triangle: find the wind
  • True course to compass heading
  • Wind triangle: heading and groundspeed
  • Off-course correction (1-in-60)
  • Runway wind components
  • Wind triangle: airspeed and heading for a groundspeed
  • True and magnetic bearings
  • Fuel volume and weight

• Pix4D overlap guidance

  Issuer: Pix4D. Edition: Vendor guidance.

  Last checked: 2026-09-23. Checked at the issuer on 2026-09-23: the PIX4Dmapper page "Selecting the Image Acquisition Plan Type" (undated) recommends at least 75% frontal and 60% side overlap in general and at least 85% frontal and side overlap for forest and dense vegetation; 85% / 70% is its snow and sand case.

  Issuer page

  1 tool cites it

  • Overlap, trigger interval, and line spacing

• Principles of Helicopter Aerodynamics

  Issuer: Cambridge University Press. Edition: 2nd edition.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  7 tools cite it

  • Battery energy (mAh to Wh)
  • Calibrate hover power from a test flight
  • Drone flight time
  • Multirotor hover power
  • Maximum payload for a flight time
  • What a payload costs in flight time
  • Return-to-home energy budget

• Range, Endurance, and Optimal Speed Estimates for Multicopters

  Issuer: IEEE Robotics and Automation Letters (Bauersfeld and Scaramuzza). Edition: Vol. 7, No. 2, pp. 2953-2960.

  Last checked: 2026-09-23. Journal version (DOI 10.1109/LRA.2022.3145063, April 2022) confirmed by search on 2026-09-23; the worked example was read in the free arXiv copy (2109.04741), Sec. VII-E.

  Issuer page

  1 tool cites it

  • Drone flight time

• Recommendation ITU-R P.525-4: Calculation of free-space attenuation

  Issuer: International Telecommunication Union. Edition: P.525-4 (08/2019).

  Last checked: 2026-09-22. Edition from the ITU-R recommendation list; not re-checked at the issuer (its site did not answer a scripted request).

  Issuer page

  1 tool cites it

  • Radio link budget

• Regulation (EU) 2019/945

  Issuer: European Commission. Edition: as amended.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  2 tools cite it

  • EASA open subcategory
  • Drone impact kinetic energy

• Regulation (EU) 2019/947

  Issuer: European Commission. Edition: as amended.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  1 tool cites it

  • EASA open subcategory

• Relationship of Topographic Relief, Flight Height, and Minimum and Maximum Overlap

  Issuer: Pryor, W. T., Bureau of Public Roads, Highway Research Board Bulletin 228. Edition: Bulletin 228.

  Last checked: 2026-09-23. Read at the TRB online publications archive on 2026-09-23: Highway Research Board Bulletin 228 (1959), pp. 28-48; the 4,444 ft example is on p. 31 and the endlap equation on pp. 36-37. A bulletin paper: it has no later edition.

  Issuer page

  1 tool cites it

  • Overlap over high terrain

• RFC 3339

  Issuer: IETF. Edition: Proposed standard.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  1 tool cites it

  • Local time to UTC (Zulu)

• S2 Geometry

  Issuer: Google. Edition: S2 Geometry library.

  Last checked: 2026-09-22. Read the S2 cell hierarchy guide at s2geometry.io on 2026-09-22: levels 0 to 30, leaf cells about 1 cm across, the cell id as face, Hilbert position, and level bits, and the token form. A living documentation site rather than an edition.

  Issuer page

  4 tools cite it

  • S2 cell details
  • S2 cells covering a region
  • S2 cell for a point
  • S2 edge neighbours

• Sentinel-2 products (SentiWiki)

  Issuer: European Space Agency and European Commission, Copernicus. Edition: SentiWiki, read 2026-09-22.

  Last checked: 2026-09-22. Read at SentiWiki on 2026-09-22: L2A_SR = (L2A_DN + BOA_ADD_OFFSET) / QUANTIFICATION_VALUE, the band-dependent offset introduced at processing baseline 04.00 on 25 January 2022, and DN 0 as no-data. A living wiki: it has no edition, so the read date stands in for one.

  Issuer page

  1 tool cites it

  • Digital number to reflectance

• Slippy map tilenames

  Issuer: OpenStreetMap Wiki. Edition: Current wiki page.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  6 tools cite it

  • One place in every index, at a matched cell size
  • Map tile bounds
  • Map tiles covering a box
  • Map tile parent and children
  • Map tile for a point (XYZ, TMS, quadkey)
  • Map ground resolution and scale

• State Plane Coordinate System of 1983 (NOAA Manual NOS NGS 5)

  Issuer: NOAA NGS. Edition: NOAA Manual NOS NGS 5.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  5 tools cite it

  • Arc-to-chord correction (t − T)
  • Latitude and longitude to state plane (SPCS83)
  • State plane (SPCS83) to latitude and longitude
  • State plane zone lookup
  • Combined scale factor (grid and ground)

• The American Practical Navigator (Bowditch), NGA Pub. No. 9

  Issuer: National Geospatial-Intelligence Agency. Edition: 2024 edition.

  Last checked: 2026-09-19. Checked at the issuer on 2026-09-19: NGA's publications API serves Bowditch_Vol_1.pdf and Bowditch_Vol_2.pdf, both titled 2024 EDITION, © 2024 NGA.

  Issuer page

  3 tools cite it

  • Dip of the horizon
  • Distance to the horizon
  • Can two points see each other?

• The Computation of Equivalent Potential Temperature (Bolton)

  Issuer: American Meteorological Society, Monthly Weather Review. Edition: Vol. 108, No. 7.

  Last checked: 2026-09-22. Checked on 2026-09-22: the DOI resolves to Monthly Weather Review vol. 108, issue 7, page 1046 at journals.ametsoc.org. A published article, not revised.

  Issuer page

  1 tool cites it

  • Cloud base and freezing level

• The GeoJSON Format (RFC 7946)

  Issuer: IETF. Edition: RFC 7946.

  Last checked: 2026-09-22. Checked at rfc-editor.org on 2026-09-22: RFC 7946, Standards Track, August 2016, not obsoleted.

  Issuer page

  5 tools cite it

  • TFR and NOTAM area
  • Export a mission (KML, GeoJSON, CSV)
  • Bounding box, antimeridian-aware
  • Check and repair a polygon
  • Range rings

• The Survey Instrumentation Calibration Technical User Manual

  Issuer: Landgate (Western Australian Land Information Authority) with ICSM. Edition: Online edition, updated 24 November 2025.

  Last checked: 2026-09-22. Section 4.2.3 read at the issuer on 2026-09-22: the IAG 1999 Resolution 3 closed formula (equations 4.6 and 4.7) and the first velocity correction (equation 4.1).

  Issuer page

  1 tool cites it

  • EDM atmospheric and prism corrections

• The use of the Normalized Difference Water Index (NDWI) in the delineation of open water features

  Issuer: McFeeters, S. K., International Journal of Remote Sensing. Edition: Volume 17, issue 7, pages 1425-1432.

  Last checked: 2026-09-22. Verified at the DOI registry on 2026-09-22: title, journal, volume, issue, pages, and year as cited.

  Issuer page

  1 tool cites it

  • NDWI (McFeeters, open water)

• Transport Canada Aeronautical Information Manual (TC AIM)

  Issuer: Transport Canada. Edition: AIM 2026-1.

  Last checked: 2026-09-23. RAC 10.2 and 10.5 read in the AIM 2026-1 RAC PDF (TP 14371E, effective March 19, 2026) on 2026-09-23. Cited for the holding entry sectors, the 5-degree zone of flexibility, and a worked holding example.

  Issuer page

  1 tool cites it

  • Holding pattern entry

• U.S. Standard Atmosphere, 1976

  Issuer: NOAA, NASA, USAF. Edition: NOAA-S/T 76-1562.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  1 tool cites it

  • Standard atmosphere

• United States National Grid

  Issuer: FGDC. Edition: FGDC-STD-011-2001.

  Last checked: 2026-09-19. Checked at the issuer on 2026-09-19: fgdc.gov serves FGDC-STD-011-2001 (PDF).

  Issuer page

  2 tools cite it

  • Latitude and longitude to USNG
  • USNG to latitude and longitude

• Use of normalized difference built-up index in automatically mapping urban areas from TM imagery

  Issuer: Zha, Y., Gao, J., and Ni, S., International Journal of Remote Sensing. Edition: Volume 24, issue 3, pages 583-594.

  Last checked: 2026-09-22. Verified at the DOI registry on 2026-09-22: title, journal, volume, issue, pages, and year as cited.

  Issuer page

  1 tool cites it

  • NDBI

• User Guidelines for Single Base Real Time GNSS Positioning

  Issuer: NOAA National Geodetic Survey. Edition: Version 3.1, April 2014.

  Last checked: 2026-09-22. Read on 2026-09-22: page 25 and the localization section.

  Issuer page

  1 tool cites it

  • RTK and PPK precision budget

• USNO Julian Date Converter

  Issuer: U.S. Naval Observatory. Edition: Online data service.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  1 tool cites it

  • Julian date, MJD, and day of year

• Vara and arpent definitions

  Issuer: Texas GLO and compiled references. Edition: Compiled definitions.

  Last checked: 2026-09-18. Checked at the issuer on 2026-09-18. Definitions cross-checked in two references.

  Issuer page

  1 tool cites it

  • Legacy land units

• Vincenty (1975) geodesics

  Issuer: Survey Review. Edition: Vol. 23, No. 176.

  Last checked: 2026-09-18. Edition taken from the research briefs (docs/research, 2026-09-18); not re-checked at the issuer yet.

  Issuer page

  2 tools cite it

  • Vincenty direct (legacy)
  • Vincenty inverse (legacy)

• Visvalingam and Whyatt (1993) line generalisation

  Issuer: The Cartographic Journal. Edition: Vol. 30, No. 1.

  Last checked: 2026-09-22. DOI resolved at doi.org on 2026-09-22; a journal article, so its edition does not change.

  Issuer page

  1 tool cites it

  • Simplify a line or polygon (Visvalingam)

• World Magnetic Model

  Issuer: NOAA NCEI and BGS. Edition: WMM2025. Valid through: 2029-12-31.

  Last checked: 2026-09-18. Checked at the issuer on 2026-09-18. WMM2025 coefficients and test values from NCEI.

  Issuer page

  5 tools cite it

  • Fix from a radial and distance
  • Magnetic declination
  • Grid variation (grivation)
  • True and magnetic bearings
  • Route legs, courses, and totals

Tracked, not cited yet

Sources the plan depends on, tracked so new editions are noticed before any tool uses them.

• 14 CFR Part 89 Remote ID (FAA (eCFR)), eCFR. Last checked: 2026-09-18.
• 47 CFR Part 15 (FCC (eCFR)), eCFR. Last checked: 2026-09-22.
• A5 pentagonal index (A5 project), pre-1.0. Last checked: not yet.
• Copernicus DEM GLO-30 (ESA and European Commission), GLO-30. Last checked: not yet.
• EGM2008 geoid (NGA), EGM2008. Last checked: not yet.
• ETSI EN 300 328 (ETSI), V2.2.2 (2019-07). Last checked: 2026-09-22.
• GEOID18 hybrid geoid (NOAA NGS), GEOID18. Last checked: not yet.
• GPX: the GPS Exchange Format (TopoGrafix), GPX 1.1. Last checked: 2026-09-19.
• NSRS 2022 products (NATRF2022, NAPGD2022, GEOID2022, SPCS2022) (NOAA NGS), beta. Last checked: not yet.
• Proposed Part 108 BVLOS NPRM (FAA and TSA), 90 FR 38212. Last checked: 2026-09-18.
• RINEX: the Receiver Independent Exchange Format (IGS and RTCM-SC104), RINEX 4.01. Last checked: 2026-09-19.
• World Magnetic Model High Resolution (NOAA NCEI and BGS), WMMHR2025. Last checked: not yet.