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geographiclib

R interface to GeographicLib for precise geodetic calculations on the WGS84 ellipsoid.

Features

Grid Reference Systems

• GARS - Global Area Reference System (military)
• Geohash - Geohash encoding/decoding with precision control
• Georef - World Geographic Reference System (aviation)
• MGRS - Military Grid Reference System encoding/decoding
• OSGB - Ordnance Survey National Grid (Great Britain)

Coordinate Parsing & Formatting

• DMS - Degrees-minutes-seconds parsing and formatting
• GeoCoords - Universal coordinate parsing (MGRS, UTM, DMS, decimal)

Map Projections

• Albers Equal Area - Equal-area conic projection
• Azimuthal Equidistant - Projection centered on any point
• Cassini-Soldner - Historical transverse cylindrical projection
• Gnomonic - Geodesics appear as straight lines
• Lambert Conformal Conic - Configurable LCC projection
• Polar Stereographic - Conformal polar projection with configurable scale
• Transverse Mercator - Custom TM projections with user-defined parameters
• UTM/UPS - Universal Transverse Mercator and Universal Polar Stereographic

Geodesic Calculations

• Geodesic direct/inverse - Distance, bearing, paths on the ellipsoid (exact and fast)
• Geodesic intersections - Find where two geodesics cross
• Nearest neighbor search - Find closest points using geodesic distance
• Polygon area - Accurate area/perimeter on the ellipsoid
• Rhumb lines - Constant-bearing paths (loxodromes)

Coordinate Transformations

• Geocentric - ECEF (Earth-Centered Earth-Fixed) coordinates
• Local Cartesian - East-North-Up (ENU) local coordinates

Ellipsoid

• Ellipsoid parameters - WGS84 parameters, curvature, auxiliary latitudes

All functions are fully vectorized with rich metadata output.

Installation

remotes::install_github("hypertidy/geographiclib")

Quick example

library(geographiclib)

# Coordinates to MGRS
pts <- cbind(lon = c(147.32, -74.01, 0.13),
             lat = c(-42.88, 40.71, 51.51))
(codes <- mgrs_fwd(pts))
#> [1] "55GEN2613352461" "18TWL8362507036" "31UCT0084710446"

# MGRS back to coordinates with full metadata
mgrs_rev(codes)
#>           lon    lat        x       y zone northp precision convergence
#> 1 147.3200014 -42.88 526133.5 5252462   55  FALSE         5  -0.2177510
#> 2 -74.0099941  40.71 583625.5 4507036   18   TRUE         5   0.6457496
#> 3   0.1299966  51.51 300847.5 5710446   31   TRUE         5  -2.2471333
#>       scale grid_zone square_100km        crs
#> 1 0.9996084       55G           EN EPSG:32755
#> 2 0.9996861       18T           WL EPSG:32618
#> 3 1.0000870       31U           CT EPSG:32631

## arguments are vectorized
rev0 <- mgrs_rev(vcodes <- mgrs_fwd(rbind(pts, pts), precision = c(0L, 1L, 2L, 3L, 4L, 5L)))
cbind(mgrs = vcodes, rev0)
#>              mgrs         lon       lat        x       y zone northp precision
#> 1           55GEN 147.6124506 -42.90097 550000.0 5250000   55  FALSE         0
#> 2         18TWL80 -73.9940004  40.69152 585000.0 4505000   18   TRUE         1
#> 3       31UCT0010   0.1249653  51.51035 300500.0 5710500   31   TRUE         2
#> 4     55GEN261524 147.3202040 -42.88010 526150.0 5252450   55  FALSE         3
#> 5   18TWL83620703 -74.0100003  40.70999 583625.0 4507035   18   TRUE         4
#> 6 31UCT0084710446   0.1299966  51.51000 300847.5 5710446   31   TRUE         5
#>   convergence     scale grid_zone square_100km        crs
#> 1  -0.4169241 0.9996308       55G           EN EPSG:32755
#> 2   0.6559370 0.9996889       18T           WL EPSG:32618
#> 3  -2.2510864 1.0000887       31U           CT EPSG:32631
#> 4  -0.2178893 0.9996084       55G           EN EPSG:32755
#> 5   0.6457454 0.9996861       18T           WL EPSG:32618
#> 6  -2.2471333 1.0000870       31U           CT EPSG:32631

Documentation

Function reference and vignettes are available at https://hypertidy.github.io/geographiclib/

Articles:

• Getting Started - Package overview and quick examples
• Geodesics - Distance, bearings, waypoints, intersections, rhumb lines, polygon area, nearest neighbors
• Grid References - MGRS, Geohash, GARS, Georef, GeoCoords, DMS formatting
• Projections - UTM/UPS, Transverse Mercator, Lambert, Albers, Polar Stereographic, and more
• Local Coordinates - Geocentric (ECEF), Local Cartesian (ENU), ellipsoid properties

Performance

Fast C++ implementation - process tens of thousands of coordinates in milliseconds:

x <- do.call(cbind, maps::world.cities[c("long", "lat")])
system.time(mgrs_fwd(x))       # 43,645 points
#>  user  system elapsed 
#>  0.04    0.00    0.04

Code of Conduct

Please note that the geographiclib project is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.

These binaries (installable software) and packages are in development.
They may not be fully stable and should be used with caution. We make no claims about them.
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