All tools

Draws the area a TFR or NOTAM describes, a circle around packed coordinates or a fix-radial-distance, or a list of points, with its area, bounds, and altitude limits, ready to download as GeoJSON.

True airspeed, Mach, and equivalent airspeed from IAS or CAS, pressure altitude, and outside air temperature, by the exact compressible-flow path, with the 2% per 1,000 ft rule beside it.

The calibrated airspeed to fly for a true airspeed or Mach number at a pressure altitude and temperature, with Mach, EAS, and impact pressure.

Static (outside) air temperature from the total air temperature a probe reads, or the reverse, with the ram rise at your Mach number.

How much to add to each procedure altitude when the airport is colder than standard, by the ICAO equation, with the 4% rule and the ICAO table beside it.

How high the airplane feels: density altitude from field elevation, altimeter setting, and temperature, with optional dew point, and the rules of thumb beside it.

The altitude on the local altimeter setting that a flight level puts you at, or the other way round, with the US lowest usable flight level and transition altitude.

The standard temperature at a pressure altitude (15 °C falling 1.98 °C per 1,000 ft to -56.5 °C), and the ISA deviation of an outside air temperature.

Pressure altitude from field elevation and the altimeter setting, exact from the standard atmosphere, with the 1,000 ft per inch rule of thumb beside it.

Converts between the altimeter setting (QNH) and station pressure (QFE) at an airport, gives the field's pressure altitude (QNE), and works out the altimeter setting from a barometer reading.

Your true height above sea level from the altimeter reading when the air is colder or warmer than standard: high to low, look out below.

An estimate of the base of convective clouds from the temperature and dew point, by the 400 ft per degree rule and by the lifting condensation level, and of the freezing level.

Dew point, relative humidity, and vapor pressure from each other, with the mixing ratio, virtual temperature, and how much lighter the moist air is than dry air.

Temperature, pressure, density, speed of sound, and viscosity of the ICAO or US 1976 standard atmosphere at any altitude, on a standard or non-standard day.

Where to start the turn onto a DME arc from a radial, and how many radials early to turn off the arc onto an inbound course, from the arc's DME and your standard-rate turn.

The distance over the ground to a DME station from the DME reading and your height above the station, and how much the reading overstates it.

Which holding entry to fly (direct, teardrop, or parallel) from your heading to the fix, the inbound course, and the turn direction, per AIM 5-3-8, with the headings for each entry.

The maximum holding airspeed for your altitude from the AIM table (200, 230, or 265 KIAS), or a published limit, with a flag when your planned speed is above it.

Inbound and outbound headings for the wind, the outbound time that gives a 1-minute inbound leg, and the triple-the-drift rule of thumb beside the exact values.

The position on a VOR radial at a distance from the station, using the station's published variation, with a warning when today's magnetic field differs from it by more than 1°.

The heading to fly to intercept a VOR radial inbound or outbound from the radial you are on now, with the intercept angle doubled from the angle off course or set by you.

How far and how long to a VOR or NDB from the time a bearing takes to change while you fly square to it, exactly and by the 60-times rule.

How much ballast at a chosen arm brings the CG to a target, and the new total weight.

Fuel for a trip by leg, with taxi and climb allowances, fuel to an alternate, and a reserve from the 14 CFR 91.151 or 91.167 minimum, checked against your usable fuel.

Fuel weight from volume, or volume from weight, for avgas or jet fuel at a nominal density or one you enter.

Reads a POH performance table of one, two, or three variables, like takeoff distance by altitude, temperature, and weight, between its listed values, refuses to guess beyond them, and applies corrections as labeled steps.

Total weight, moment, and center of gravity from your stations, checked against your CG envelope at takeoff and after the fuel burn.

How far the CG moves when you move weight from one station to another, or how much weight to move to put the CG where you need it.

Converts a climb or descent gradient (feet per nautical mile, percent, or degrees) to the vertical speed you need at a groundspeed, or the reverse.

How far you can glide from a height with your aircraft's glide ratio, in still air and with a headwind or tailwind.

The pivotal altitude for eights on pylons at your groundspeed, with the knots-squared over 11.3 rule.

How far each gallon of fuel takes you, through the air and over the ground, and the fuel each 100 NM takes, from your airspeed and fuel flow.

Where to start down: descent distance, vertical speed, and time for an altitude change on a descent angle or at a vertical speed, with the 3-to-1 and 5 × groundspeed rules beside them.

Bank angle, rate of turn, turn radius, load factor, and stall speed in the turn, from true airspeed and a bank angle or turn rate (standard rate by default).

The visual descent point for a non-precision approach: the distance from the threshold where a normal descent from the MDA begins, with the HAT/300 rule and the descent rate at your groundspeed.

Decodes FB winds and temperatures aloft: one group at a level, or a whole station line, with light-and-variable winds, speeds over 100 kt, and the implied minus sign above 24,000 ft.

Turns a pasted METAR or SPECI into plain language: wind (true), visibility, weather, clouds and ceiling, temperature, altimeter, US remarks, and the flight category. Groups it cannot read are listed, never dropped.

Turns a pasted TAF into a timeline of forecast periods (FM, TEMPO, BECMG, PROB30/40) in plain language, with UTC and local times, winds (true), visibility, weather, clouds and ceilings, and flight categories.

The wind and temperature at your cruising altitude from the forecast levels above and below it, interpolated as a vector so a turning wind turns smoothly.

Headwind and crosswind on every runway at an airport for one wind, ranked by headwind, with runways beyond your limits flagged.

Where a heading and true airspeed will take you in a known wind: the course over the ground, the groundspeed, and the drift.

The wind aloft from your heading, true airspeed, track, and groundspeed.

From true course through the wind correction, variation, and your compass deviation card to the heading to fly on the compass, each step shown.

The heading to fly and the groundspeed you will get for a course, true airspeed, and wind: the E6B wind side, exact.

How far you have drifted off track, the turn to parallel your course, and the turn to reach your destination, exactly and by the 1-in-60 rule.

Crosswind and headwind or tailwind on a runway, with gusts, variable winds, and your personal limits.

The true airspeed and heading that make good a course at the groundspeed you need, for a known wind.

A wind's east-west (u) and north-south (v) components from its direction and speed, or the direction and speed from u and v, as weather models and forecasts give them.

Free-space path loss, received signal, and fade margin for a control or video link, with the transmitter's EIRP checked against the dated 2.4 GHz limit where you fly.

Parallel flight lines that follow a centerline (a pipeline, road, or river) across a corridor width, with the line count from your spacing, flown back and forth.

Waypoints written as a KML file with the right altitude mode, GeoJSON with each waypoint's details, or CSV, labeled with the height reference and a not-for-navigation notice.

Waypoints for photographing a building face: level passes at a fixed standoff, stacked up the wall with the overlap you set, and the GSD on the facade.

A fence a set distance around a point, route, or area, with an optional inner warning fence, its area and perimeter, and any waypoint that falls outside.

Waypoints on a geodesic circle around a point, each with the heading toward the center and the gimbal pitch that keeps a target height centered, like the top of a tower.

A serpentine mapping pattern over an area, with no-fly holes routed around, the fewest lines by default, overshoot, and an optional crosshatch: waypoints, line count, path length, turns, photo count, and flight time.

Which EU open-category subcategories (A1, A2, A3) your drone may fly in, from its class mark and mass, with each subcategory's distance rule.

Kinetic energy ½mv² in joules and foot-pounds, compared with the EASA C1 80 J threshold and the FAA category 2 operations-over-people 11 ft-lb threshold, each cited.

Your maximum altitude under 14 CFR 107.51: 400 ft above ground, or up to 400 ft above a structure when you stay within 400 ft of it, shown above ground, above sea level, and above the ellipsoid.

Checks your groundspeed, including the wind, against the Part 107 limit of 87 kt (100 mph). A tailwind can push a legal airspeed over the limit.

The height above ground that gives a target ground sampling distance with your camera, checked against your altitude ceiling.

Horizontal and vertical accuracy by the ASPRS Positional Accuracy Standards, Edition 2, including the checkpoint survey's own error and the 30-checkpoint minimum.

How much ground each pixel covers, and the image footprint, from the camera and height above ground; catches 35 mm-equivalent focal lengths entered by mistake.

How many photos, flight lines, and kilometers a mapping survey of an area takes at your line and photo spacing, counted the way published flight planning counts them and from the same sweep the survey-grid tool flies.

How many pixels the image smears at your speed and shutter, and the slowest shutter that keeps blur under a limit.

For a camera tilted off straight down, the ground each pixel covers at the image center and its near and far edges, the trapezoid the image covers, and a warning when the view reaches the horizon.

A mission flown at one height above takeoff is closer to the ground over hills, so photos cover less and overlap drops. The lowest overlap and the height left over the highest ground.

Photo spacing, trigger interval, and flight-line spacing for your front and side overlap, with a check that the camera can keep up.

Battery energy in watt-hours from capacity and voltage (or cell count), usable energy after a discharge limit and landing reserve, and the current and C-rate for a power draw.

Back-solve a multirotor's real figure of merit × efficiency from a measured hover: the energy it drew and for how long, so the hover-power and flight-time tools match your aircraft.

Hover and cruise flight time from usable battery energy and power draw, with the landing reserve and cold-battery derating shown, and range at a groundspeed.

Electrical hover power for a multirotor from its mass, rotors, and air density, by momentum theory with a figure of merit and motor efficiency, never the ideal power alone.

The most payload a multirotor can carry and still hover for a target time, from its mass, rotors, battery energy, and air density by momentum theory.

The extra hover power and the flight time lost when a multirotor carries a payload, from its mass and any electrical draw, by momentum theory.

Whether the battery can bring the drone home against the wind: return groundspeed, time, energy, the margin left, and the farthest round trip that keeps the reserve.

An estimate of how much storage a mapping job needs: the raw images, the orthomosaic (uncompressed and over a compression range), and a lidar point cloud as LAS and LAZ.

Swath, line spacing, and pulse density for a lidar flight, with the aggregate density over overlapping lines checked against the USGS 3DEP quality levels.

How much ground or surface one thermal pixel covers at a distance, the smallest target you can measure reliably, and how far away you can be for a target size.

How far you can keep a drone in visual line of sight by EASA guidance: attitude line of sight from its size, detection line of sight from visibility, and the smaller of the two, checked against your farthest point.

Applies a 7-parameter Helmert transformation, or a 14-parameter time-dependent one with rates, to ECEF coordinates, in the position-vector or coordinate-frame convention you name, forward or exactly reversed.

Transforms a position between International Terrestrial Reference Frame realizations (ITRF2020 back to ITRF88) and the WGS 84 realizations aligned with them, at the coordinates' epoch, with the IERS parameters.

Converts a latitude and longitude between a legacy datum (ED50, NAD27, OSGB36, Tokyo, AGD66, Pulkovo 1942, SAD69, or Arc 1960) and WGS 84 with the published EPSG transformation, and states its accuracy, which is meters, not centimeters.

Transforms a position between NAD 83 (2011, PA11, or MA11) and ITRF2020, ITRF2014, ITRF2008, ITRF2005, ITRF2000, or WGS 84 at one epoch, with the NGS HTDP parameters, and shows the meter-level difference between them.

Converts a latitude and longitude from a region's old datum to NAD 83 with the NGS NADCON5 grids, or back: NAD 27 in the conterminous US and Alaska, Old Hawaiian, Puerto Rico 1940, St. Paul 1952, American Samoa 1962, and Guam 1963.

Propagates an ITRF2020 position from one epoch to another with the rigid-plate velocity of its tectonic plate, or with a site velocity you give, and flags zones where plates deform and rigid motion does not apply.

Converts between geodetic latitude and the geocentric, parametric (reduced), rectifying, conformal, authalic, and isometric latitudes, in either direction.

The defining and derived parameters of a reference ellipsoid: semi-minor axis, flattening, eccentricities, third flattening, and the mean, authalic, and volumetric radii.

At a latitude: the meridional and prime-vertical radii of curvature, their Gaussian mean, the radius in any azimuth, the length of one degree of latitude and longitude, and the meridian arc from the equator or between two latitudes.

Converts Earth-centered, Earth-fixed X, Y, Z to geodetic latitude, longitude, and ellipsoidal height, in closed form at any height.

Finds the latitude, longitude, height, and ECEF position of a point given in a local tangent plane at an origin: east-north-up, north-east-down, or azimuth-elevation-range.

Converts geodetic latitude, longitude, and ellipsoidal height to Earth-centered, Earth-fixed X, Y, Z.

Expresses a target point in a local tangent plane at an origin: east-north-up, north-east-down, and azimuth-elevation-range, with the rotation matrix on request.

The geoid height N (geoid undulation) above the WGS 84 ellipsoid at any point from the EGM96 global geoid, the number that turns GPS ellipsoidal heights into heights above mean sea level.

Encodes a latitude and longitude as a Global Area Reference System cell: 30′ cell, 15′ quadrant, or 5′ keypad, with its bounds.

Decodes a Global Area Reference System code (5 to 7 characters) to the center and bounds of its cell, quadrant, or keypad.

Encodes a latitude and longitude in the World Geographic Reference System (GEOREF) from a 15° tile down to thousandths of a minute, with the cell's bounds.

Decodes a World Geographic Reference System (GEOREF) code to the center and bounds of its cell.

Encodes a latitude and longitude as a Maidenhead (QTH) locator of 2 to 10 characters, as used in amateur radio, with the cell's bounds.

Decodes a Maidenhead (QTH) locator of 2 to 10 characters, in any letter case, to the center and bounds of its cell.

Encodes a WGS 84 latitude and longitude as an MGRS grid reference at any precision, truncating (never rounding) as the standard requires.

Decodes an MGRS or USNG grid reference to the south-west corner and center of the square it names, with the square's size.

Encodes a latitude and longitude as a U.S. National Grid reference, written with spaces (17T NE 86309 77770), truncating to the precision chosen.

Decodes a U.S. National Grid reference, including a truncated local one like NE 863 777 when you give the grid zone, to the center and south-west corner of the square it names.

Converts a GPS ellipsoidal height to height above mean sea level (orthometric) or back, with h = H + N and the EGM96 geoid height N.

Magnetic declination (variation), inclination, and field strength at any place and date from the World Magnetic Model 2025 or IGRF-14, with the model's uncertainty and compass warning zones.

The angle from grid north (UTM or UPS) to magnetic north, for navigating by a grid near the poles or on military maps: declination minus grid convergence, with the sign convention stated.

Converts a true bearing to magnetic or back, with a chart variation like 12°W, the magnetic model at a place and date, or both side by side.

Adds and subtracts angles in degrees, minutes, and seconds (or decimal degrees), carrying seconds and minutes exactly, with the result normalized to 0-360° or ±180° if you like.

The smallest signed turn from one bearing to another, across north when needed.

Reads a coordinate in almost any notation (decimal, DMS, DDM, packed aviation, labeled, MGRS, or UTM) and reports what it assumed.

Writes a latitude and longitude as decimal degrees, DMS, or DDM with the precision you choose, and tells you what that precision means on the ground.

The small angle between a line's straight grid bearing and its curved projected geodesic, at each end, in UTM or a State Plane zone, with the grid and ellipsoid distances.

Converts NAD83 latitude and longitude to State Plane Coordinate System of 1983 easting and northing in any of the 124 zones, in meters, international feet, or US survey feet, with convergence and scale factor.

Converts SPCS83 easting and northing in any of the 124 zones back to NAD83 latitude and longitude, with convergence and scale factor.

Finds SPCS83 zones by state or zone name, or the zones whose area of use covers a point, with each zone's NGS code, EPSG code, projection, and feet unit.

Converts polar coordinates (84° N and beyond, or 80° S and beyond) to Universal Polar Stereographic easting and northing.

Converts a Universal Polar Stereographic easting and northing back to latitude and longitude.

Converts a latitude and longitude to UTM zone, easting, and northing, with the Norway and Svalbard zone exceptions, an optional forced zone, and the grid convergence and scale factor.

Converts a UTM zone, hemisphere, easting, and northing back to latitude and longitude, with the grid convergence and scale factor.

The UTM zone and MGRS latitude band for a point, including the Norway and Svalbard exceptions, and the zone's central meridian.

The area and perimeter of a polygon with geodesic edges on WGS 84 (or any ellipsoid), with holes, across the antimeridian or around a pole, and its ring orientation.

The area within a distance of a point, line, or polygon on the ellipsoid, or a polygon shrunk inward, with round, mitre, or bevel corners, measured back against the input.

How far apart two GPS tracks or routes are: the discrete Fréchet distance (the leash two walkers need, with where it is tightest), the Hausdorff distance, and their closest approach.

Triangles joining a set of points so no point sits inside any triangle's circumcircle: planar on a local map for a regional set, or on the sphere for a global one.

The region nearest each point (its Voronoi cell), planar on a local map within a box around the points, or on the whole sphere for a global set.

Where two areas overlap, their combined outline, what one has that the other lacks, or both, as valid polygons with geodesic areas, like the overlap of two geofences.

Whether points are inside a polygon with geodesic edges, by the winding rule and the even-odd rule, with holes, on the boundary within 1 mm, and how far each is from the edge.

The smallest latitude and longitude box around points, a line, or a polygon, written west-south-east-north, crossing the antimeridian when that is shorter and reaching a pole a polygon circles.

The center of mass of a polygon on the ellipsoid, a warning when it falls outside the shape, and a point guaranteed inside, as far from the edges as possible, for a label or a pin.

Adds vertices along each edge of a line or polygon so no piece is longer than a set length, each on the true geodesic, so maps that draw straight segments still follow the Earth's curve.

Around a set of points: the convex hull, the smallest rotated rectangle, and the smallest circle that holds them all, with its center and geodesic radius.

Removes vertices from a line or polygon while keeping every removed vertex within a distance tolerance of the simplified geodesic edges, optionally without letting edges cross, and reports the largest deviation.

Removes the vertices that make the smallest triangles with their neighbors, down to an area threshold or a target number of vertices, optionally without letting edges cross, and reports the largest deviation.

Finds what is wrong with a polygon (crossed or touching edges, duplicate corners, spikes, holes outside the outline, clockwise rings), says where, and returns a repaired version: a bow-tie becomes two triangles.

A point written as an H3 cell, an S2 cell, a geohash, a Plus Code, a map tile, a Maidenhead locator, and an MGRS reference, each at the resolution whose cell is closest to the size you name, with the size it actually has there.

Every geohash at a precision that touches a bounding box or polygon, or only those whose centers fall inside, for indexing or querying an area.

The center, bounding box, and error margins of a geohash.

The geohash for a latitude and longitude at precision 1 to 12, with the cell's size and bounds.

The 8 geohash cells around a geohash, wrapping across the antimeridian; past a pole there is no neighbor.

Everything about an H3 cell: center (cellToLatLng), boundary (cellToBoundary), resolution, base cell, pentagon and Class III checks, area, and decimal form.

The local IJ coordinates of a cell as seen from an origin cell: two whole numbers on the grid H3 unfolds around that origin.

The outline of a set of H3 cells: the boundary between the set and everything outside it, as polygons with their holes, in GeoJSON.

The finer H3 cells inside a cell (cellToChildren), their count, and the center child.

Replaces every complete group of 7 sibling cells with their parent, repeatedly, for the smallest set covering the same area (compactCells).

The directed edges (with lengths and neighbors) and vertexes of an H3 cell (originToDirectedEdges, cellToVertexes).

All H3 cells within k steps of a cell (gridDisk); fewer than 3k(k+1)+1 when a pentagon is nearby.

The grid distance between two H3 cells (gridDistance) and the line of cells joining them (gridPathCells).

The H3 cells exactly k steps from a cell (gridRing), the hollow ring.

The H3 cell containing a latitude and longitude at resolution 0 to 15 (latLngToCell), with the cell's center and area.

The H3 cell at local IJ coordinates around an origin cell, undoing cellToLocalIj.

The coarser H3 cell that contains a cell (cellToParent), and the cell's position among that parent's children.

The H3 cells that fill a polygon (with holes, across the antimeridian) at a resolution, by an explicit containment mode: cell centers inside, whole cells inside, or any overlap.

The H3 resolution whose average cell is closest to a target area or edge length, with the full resolution table (122 base cells, 12 pentagons at each resolution).

Expands a mixed-resolution set of H3 cells to one resolution (uncompactCells).

The center and area of a Plus Code; a short code needs a nearby reference point to recover the full code.

The Plus Code (Open Location Code) for a latitude and longitude at code length 2 to 15, with the area it covers.

The shortest form of a full Plus Code that still recovers uniquely near a reference point (such as the nearest town).

Everything about an S2 cell: its center, its four corners, the face and level, its exact area against the average for that level, and its parent and children.

The S2 cells that cover a latitude and longitude rectangle, or a circle around a point, within a level range and a cell budget.

The S2 cell containing a latitude and longitude at a level from 0 to 30, with its token, its 64-bit id, the face it sits on, and its area.

The four cells across an S2 cell's edges, at the same level, wrapping onto the next cube face where the cell lies on a face edge.

The latitude and longitude bounds of a z/x/y tile or quadkey, with its XYZ, TMS, and quadkey forms; detect mode shows both y conventions.

Every z/x/y tile at a zoom that touches a latitude and longitude box, across the antimeridian when west is greater than east, for pre-caching or download planning.

The parent tile one zoom out and the four children one zoom in of a z/x/y tile or quadkey, in XYZ or TMS numbering.

The web map tile containing a point at a zoom: XYZ, TMS, and quadkey, with the ground resolution.

Meters per pixel and map scale for a Web Mercator zoom level at a latitude, for 256 or 512 pixel tiles.

Where you end up after traveling a distance on an initial course along the ellipsoid, any length, with Karney's algorithm.

The great-circle distance on a sphere by the haversine formula, with its error against the ellipsoidal geodesic shown.

The point a given fraction of the way between two points along the great circle on a sphere, beside the same fraction along the ellipsoidal geodesic.

The crossing of the geodesics through two segments on the ellipsoid, nearest the segments' middles, and whether it falls within both segments or out on their extensions.

The shortest distance and the start and end courses between two points on the WGS 84 ellipsoid (or any ellipsoid), exact to nanometers with Karney's algorithm.

The point halfway along the shortest path between two points on the ellipsoid, and the course there.

Where a great circle from a start point on a course takes you after a distance on a sphere, and how far that is from the ellipsoidal answer.

Distance and initial and final courses along the great circle on a sphere, with the difference from the ellipsoidal geodesic shown.

The vertex of a geodesic: the northernmost point it reaches, where it runs due east or west, and how far along the line from the start it lies.

The destination by Vincenty's 1975 method, for checking legacy software; reports how far it lands from the Karney destination.

Distance and courses by Vincenty's 1975 method, for checking legacy software; reports its difference from Karney and fails honestly near antipodes.

Points along the geodesic (or rhumb line) from A to B at N equal intervals, a fixed spacing, or given fractions, with distance and course at each, as a table, a GPX route, and GeoJSON.

How far below eye level the visible horizon lies from a height, with refraction, and the navigator's 1.76′√h rule with its difference.

The first Fresnel zone radius at a point on a radio link, the 60% clearance it needs, and the Earth's bulge there, summed into the clearance above a smooth Earth.

How far you can see from a height: the horizon distance with no refraction, with optical refraction, and for radio (4/3 Earth), with the rules of thumb and their errors.

The farthest two raised points can see each other over the Earth's curve, and for a given distance whether they can, the clearance at the midpoint, and how much of the far target is hidden.

Where a constant course (rhumb line, loxodrome) for a given distance ends on the ellipsoid; a rhumb that would cross a pole stops there.

The constant course and distance of the rhumb line (loxodrome) between two points on the ellipsoid, and how much longer it is than the shortest route.

The point on a multi-leg route closest to a position: which leg, how far along the route, and how far off it (right of course positive).

The point where two courses from two positions meet, on geodesics or rhumb lines, and how far each has to run to get there.

When two moving objects come closest, how close, and the bearing and range then, in a local flat frame (for separations under 500 km), with climb rates and height for aircraft in 3D.

How far a point is off the course line from A to B (right of course positive), how far along the course its closest point lies, and that point, on the ellipsoid to the millimeter.

How early to start a fly-by turn at a waypoint: turn radius, lead distance, arc length, and time in the turn, from the inbound and outbound courses, speed, and bank angle or turn rate.

The course to steer, the time, and the meeting point for reaching a target that is moving on a steady course and speed, or why it cannot be reached.

Each leg's distance, true and magnetic course, and cumulative distance for a route of waypoints, with leg times and arrival times from a groundspeed and departure time.

Geodesic circles at one or more distances around a point, drawn true on the ellipsoid, with their areas, and a GeoJSON file cut correctly at the antimeridian and around a pole.

Solves for time, speed, or distance from the other two, and the arrival time from a departure time and UTC offset.

The straight-line distance between two points with heights, such as a drone and its ground station, through Earth-centered coordinates, with the ground distance, height difference, and elevation angle.

Azimuth, elevation, and straight-line range from an observer to a target, both with heights above the ellipsoid, with a warning when the Earth's curve hides the target.

Adds any number of 2D or 3D vectors head to tail; for two vectors, also their difference, dot and cross products, the angle between them, and the projection of one on the other.

Turns a magnitude and direction (and elevation, for 3D) into x, y, and z components, or components back into magnitude and direction, with the direction convention stated: navigational from north or mathematical from +x.

Evaluates your own expression over named bands: arithmetic, comparisons, a conditional, and a short list of functions, parsed and evaluated in the core rather than by a JavaScript evaluator.

The difference between a pre-fire and a post-fire normalized burn ratio, with the published severity ranges it is usually read against.

The enhanced vegetation index from blue, red, and near-infrared reflectance, which stays responsive over dense canopy where NDVI saturates.

The two-band enhanced vegetation index from red and near-infrared reflectance, which tracks EVI without needing a blue band.

The modified normalized difference water index from green and shortwave-infrared reflectance, which separates water from built-up surfaces better than NDWI.

The normalized burn ratio from near-infrared and the longer shortwave-infrared band, the index burn severity is measured with.

The normalized difference built-up index from shortwave-infrared and near-infrared reflectance, which highlights roofs, roads, and other built surfaces.

The normalized difference vegetation index from near-infrared and red surface reflectance, the standard measure of how much green vegetation a pixel holds.

The normalized difference water index of Gao 1996, from near-infrared and shortwave-infrared reflectance: the one that measures liquid water in vegetation.

The normalized difference water index of McFeeters 1996, from green and near-infrared reflectance: the one that maps open water.

The soil-adjusted vegetation index from red and near-infrared reflectance, with the soil adjustment factor L, for scenes where bare ground shows through.

Turns a band's stored digital number into surface reflectance with its sensor's own scaling: the Sentinel-2 Level-2A offset and quantification value, or the Landsat Collection 2 gain and offset.

The terrain ruggedness index, topographic position index, and roughness for the center of a 3 x 3 elevation window.

Slope, aspect, and hillshade for the center of a 3 x 3 elevation window by Horn's method, with the cell size corrected for latitude on a degree-based grid.

How far a loop traverse's measured angles miss their geometric sum, (n − 2) × 180° for interior angles, against an allowable K√n, with the angles balanced.

The area enclosed by plane-survey coordinates by the coordinate (shoelace) method, in square units, acres, and hectares, with the perimeter.

The coordinates of a point from a known point, a bearing or azimuth, and a horizontal distance (a radial sideshot).

Where two lines cross, a line meets a circle, or two circles meet: bearing–bearing, bearing–distance, and distance–distance intersections from two known points, every solution returned and labeled.

The bearing, azimuth, and horizontal distance between two plane-survey coordinates (northing, easting).

Adjusts a small horizontal network of distances, angles, and direction sets by weighted least squares, with adjusted coordinates, standard errors, 95% error ellipses, the reference variance, and a chi-square test.

The coordinates of a point the prism cannot sit on: from a shot beside it with left, right, in, or out offsets, or from an angle offset to the center of a tree or pole.

The coordinates of an occupied station from the angles it turned between three known points, by Tienstra's method, with a warning when the station is near the danger circle.

A point's station and offset from a straight alignment, with the foot of its perpendicular, or the point at a given station and offset. Offsets are positive to the right.

Latitudes, departures, linear misclosure, and precision ratio for a closed loop traverse, adjusted by the compass (Bowditch), transit, or Crandall rule.

All elements of a simple circular curve (radius, deflection, tangent, length, chord, external, middle ordinate, degree of curve) from any two, with PC and PT stations.

PC and PT stations for a circular curve and a layout table at a chosen interval: station, deflection from the PC, chords, and coordinates when the PI position and back tangent are given.

The shortest crest or sag vertical curve that gives a sight distance, from the standard formulas with your eye, object, or headlight heights, stating which case applies; design values come from your design manual.

The elements of a clothoid spiral-curve-spiral (spiral angle, X, Y, p, k, long and short tangents, total tangent), its TS, SC, CS, and ST stations, and deflections along the spiral.

A vertical curve with different tangent lengths each side of the PVI: PVC, PVT, and the point under the PVI, the high or low point, and the elevation at any station.

PVC and PVT stations and elevations, the high or low point, and the K value of a symmetric parabolic vertical curve.

Earthwork volume between two cross-sections by the average end area method, in cubic yards and cubic feet.

Cut and fill over a grid of existing elevations against a finished grade: the net volume by corner weights and the four-point method, with the balance line where cut turns to fill.

A construction side slope or grade with its ratio labeled H:V and V:H, refusing an unlabeled 3:1, with rise, run, or slope length from any two; for a plain unit conversion of a slope, use the slope converter.

Earthwork volume by the prismoidal formula with a measured middle section, and its difference from the average end area method.

The grade of every segment along an elevation profile, the steepest and average grade, total climb and descent, and each segment steeper than your limit flagged.

Cut and fill areas between the existing ground and a design template across one station, each split where the two cross, with the grade points where they meet.

Loose and compacted volumes from a bank volume with your swell and shrink factors, and the truck loads to haul it.

Where a road template's cut or fill slope meets existing ground on one side, its offset and the cut or fill to the shoulder, found by iteration and written in stake notation.

The volume of a cone, frustum, or prism from its dimensions, or of a conical pile from its base and an angle of repose you enter with its source.

A stockpile's volume from its base outline and surface shots: a Delaunay TIN measured above the plane fitted to the base, in cubic units and cubic yards.

The vertical height to the antenna reference point from a slant height measured to the edge of the antenna, its radius, and the mark-to-ARP offset.

Fits local site coordinates to grid coordinates through control points seen in both, by a similarity (scale, rotation, shift) or affine transform, with residuals, their root mean square, and a check for a feet-and-meters mix-up.

Which NGS OPUS processing a planned GNSS session gets (rapid-static or static), whether its length qualifies, and the RINEX file name for the day.

The precision a receiver's a mm + b ppm specification promises over your baseline, horizontal and vertical, scaled to a confidence level and compared with your target.

The allowable relative positional precision between two adjacent boundary corners under the 2026 ALTA/NSPS standards, compared with the 95% error ellipse from your adjustment.

Rotates deed or plat bearings to a new basis of bearing (like grid north) from one line whose bearing is known in both, and reports the rotation angle.

Turns pasted metes-and-bounds deed text into a table of calls (bearings, distances, curves, and monuments) for you to confirm and edit before anything is plotted.

Plots confirmed deed calls (lines and curves), then reports the misclosure, its direction, the precision ratio, and the area closed by the implied closing line. Courses are never adjusted unless you choose to.

Converts chains and links, rods, furlongs, varas, and arpents from old deeds and plats to US survey feet, feet, and meters, with the definition used; varas and arpents need a jurisdiction.

Reads a Public Land Survey System description like NE¼ SW¼ Sec 12, T3N R4W, 6th PM into plain words, and gives the nominal aliquot area of a standard 640-acre section.

The elevation factor and combined factor from a grid scale factor and height, and conversion of a distance between grid and ground.

How much the earth's curve, less the bending of the line of sight, lowers a level sight over a distance, with the textbook coefficient for the refraction coefficient used.

Corrects a measured EDM distance for the air it traveled through (in ppm, entered or worked out from temperature, pressure, and humidity) and for the prism constant, each listed.

The height of a tower, tree, or building you cannot reach, from zenith angles to its base and top and a horizontal distance, or from two stations in line with it.

Heights of instrument and elevations from a level book, the arithmetic check, and for a loop or a run between benchmarks, the misclosure, its allowable, and the adjusted elevations.

Horizontal distance, vertical difference, and elevation difference from a slope distance and zenith angle, with two-face means and the curvature and refraction correction for long sights.

Horizontal distance, vertical difference, and elevation difference from a stadia rod interval and the sight's zenith angle.

The time between out and in (block time or flight time), across midnight and across UTC dates, in hours and minutes and decimal hours.

Converts decimal hours to hours and minutes (1.3 h is 1:18, not 1:30) and back.

The UTC time for a GPS week and seconds of week, including 10-bit weeks with their rollover era.

The GPS week, seconds of week, 10-bit week and rollover era, and the GPS − UTC and TAI − UTC offsets for a UTC time.

The Julian date, modified Julian date, and day of year for a UTC time (or the time for a JD or MJD), with the RINEX daily file name.

Converts a local time to UTC and Zulu time with an IANA time zone or a UTC offset, or UTC to local, handling daylight saving gaps and overlaps and showing the date change.

The UTC offset, abbreviation, and daylight saving state of an IANA time zone at a moment, and when it next changes.

All four US aviation night periods for a place and date, each with its regulation: logging night, passenger-currency night, position lights, and Part 107 civil twilight.

Sunrise, sunset, solar noon, day length, and civil, nautical, and astronomical twilight for a place and local date, in local time and Zulu, with polar states.

Whether the hotspot, the bright patch where the camera looks straight away from the sun, falls in a camera's frame for its heading and pitch at a place and time, and how far off it is.

The part of a day when the sun is above an elevation threshold (default 30°) for aerial mapping, in local time and Zulu, with the day's highest sun.

Which of your logged night takeoffs and full-stop landings count toward 14 CFR 61.57(b), whether you are current to carry passengers at night on a date, and the day that currency lapses, per category and class.

The sun's azimuth, elevation, declination, and hour angle for a place and time by the NREL Solar Position Algorithm, with the NOAA result as a cross-check, shadow length, and incidence on a slope.

Converts accelerations: m/s², standard gravity (g), and ft/s².

Converts angles: degrees, radians, gons, arcminutes, arcseconds, turns, and the four kinds of mil.

Converts turn and rotation rates: °/s, °/min, rad/s, rpm, and arcsec or mas per year.

Converts areas: m², km², hectares, acres, ft², mi², and NM².

Converts battery charge between mAh, Ah, and coulombs, and to watt-hours at a stated voltage.

Converts data rates: bit/s, kbit/s, Mbit/s, and Gbit/s.

Converts densities: kg/m³, g/cm³, lb/US gal, and lb/ft³.

Converts energy: J, kJ, MJ, Wh, kWh, and foot pounds-force.

Converts frequencies: Hz, kHz, MHz, GHz, and drift rates in ppm or ppb per year.

Converts fuel between volume and weight using a density you choose or a nominal fuel type.

Converts lengths and distances: m, km, ft, US survey ft, in, yd, mi, and NM.

Converts masses: kg, g, lb, oz, and metric tonnes.

Converts power: W, kW, and mechanical horsepower (550 ft·lbf/s).

Converts pressures: inHg, hPa, mbar, Pa, kPa, bar, psi, mmHg, and atm.

Reads any value with a unit, like “145 kts”, and returns it in canonical units (SI; degrees for angles).

Converts a slope between rise/run ratio, percent grade, per mille, and degrees.

Converts speeds: knots, mph, km/h, m/s, and ft/s.

Converts temperature differences, like ISA deviation: a change of 1 °C is 1 K and 1.8 °F.

Converts temperatures between °C, °F, and K.

Converts durations: seconds, milliseconds, minutes, hours, and days.

Converts climb and descent rates: ft/min, m/s, m/min, and ft/s.

Converts volumes: m³, liters, US and imperial gallons, ft³, and yd³.