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Geo-H3-0.10
⭐ Starred 2 / Geo::H3

NAME

Geo::H3 - H3 Geospatial Hexagon Indexing System

SYNOPSIS

use Geo::H3;
my $gh3      = Geo::H3->new;

my $hex      = $gh3->h3(uint64 => $int);        #isa Geo::H3::Index
my $hex      = $gh3->h3(string => $string);     #isa Geo::H3::Index

my $geo      = $gh3->geo(lat=>$lat, lon=>$lon); #isa Geo::H3::Geo
my $hex      = $geo->h3($resolution);           #isa Geo::H3::Index

my $center   = $h3->center;                     #isa Geo::H3::GeoCoord
my $lat      = $center->lat;                    #isa Double WGS-84 Decimal Degrees
my $lon      = $center->lon;                    #isa Double WGS-84 Decimal Degrees
my $distance = $center->distance($geo);         #isa Double meters

DESCRIPTION

This Perl distribution provides a Perl Object Oriented interface to the H3 Core Library. It accesses the H3 C library using libffi and FFI::Platypus.

H3 is a geospatial indexing system that partitions the world into hexagonal cells. Please note that a very few number of cells are pentagons but we use the terms hex or hexagon to include pentagons.

The H3 Core Library implements the H3 grid system. It includes functions for converting from latitude and longitude coordinates to the containing H3 cell, finding the center of H3 cells, finding the boundary geometry of H3 cells, finding neighbors of H3 cells, and more.

The H3 Core Library can be installed from Uber's H3 repository on GitHub https://github.com/uber/h3 which is well documented at https://h3geo.org/docs/.

CONVENTIONS

The Geo::H3 lib is an Object Oriented wrapper on top of the Geo::H3::FFI library. Geo::H3 was written as a wrapper so that in the future we are able to re-write against different backends such as the yet to be developed Geo::H3::XS backend.

libh3

- Latitude and longitude cordinates are in radians WGS-84
- H3 Index values are handled as uint64 integers
- GeoCoord values are handled as C structures with lat and lon
- GeoBoundary values are handled as C structures with num_verts and verts

Geo::H3::FFI

- Latitude and Longitude cordinates are in radians WGS-84
- H3 Index values are handled as uint64 integers
- GeoCoord values are handled as Geo::H3::FFI::Struct::GeoCoord objects
- GeoBoundary values are handled as Geo::H3::FFI::Struct::GeoBoundary objects

Geo::H3

- Latitude and longitue cordinates are in decimal degrees WGS-84
- H3 Index values are handled as Geo::H3::Index objects
- GeoCoord values are handled as Geo::H3::GeoCoord objects
- GeoBoundary values are handled as Geo::H3::GeoBoundary objects

CONSTRUCTORS

h3

Returns a Geo::H3::Index object

my $hex = $gh3->h3(unit64 => $int);                  #isa Geo::H3::Index
my $hex = $gh3->h3(string => $string);               #isa Geo::H3::Index
my $hex = Geo::H3::Index->new(uint64 => $h3_uint64); #isa Geo::H3::Index
my $hex = Geo::H3::Index->new(string => $h3_string); #isa Geo::H3::Index

geo

Returns a Geo::H3::Geo object

my $geo = $gh3->geo(lat=>$lat_deg, lon=>$lon_deg);         #isa Geo::H3::Geo
my $geo = Geo::H3::Geo->new(lat=>$lat_deg, lon=>$lon_deg); #isa Geo::H3::Geo

ffi

Returns the Geo::H3::FFI object.

LIMITATIONS

This package uses the naming convention of version 3.x of the Uber H3 library. The organization that maintains the open source Uber H3 library has not maintained backward compatibility in version 4.x. This Perl distribution currently sees no reason to support the 4.x version of the Uber H3 library as the 3.7.2 release is stable and full featured.

SEE ALSO

https://h3geo.org/docs/3.x/, https://github.com/uber/h3/tree/stable-3.x, Geo::H3::FFI

AUTHOR

Michael R. Davis

COPYRIGHT AND LICENSE

MIT License

Copyright (c) 2021 Michael R. Davis