Author image šŸ—²Michael R. Davisāš

NAME

Geo::H3 - H3 Geospatial Hexagon Indexing System

SYNOPSIS

  use Geo::H3;
  my $gh3      = Geo::H3->new;
  
  my $h3       = $gh3->h3(index  => $int);        #isa Geo::H3::Index
  my $h3       = $gh3->h3(string => $string);     #isa Geo::H3::Index

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

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 longitue 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 Longitue 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 $h3 = $gh3->h3(index  => $int);             #isa Geo::H3::Index
  my $h3 = $gh3->h3(string => $string);          #isa Geo::H3::Index
  my $h3 = Geo::H3::Index->new(index => $index); #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

SEE ALSO

https://h3geo.org/, https://github.com/uber/h3/, Geo::H3::FFI

INSTALLATION

Geo::H3 has some pretty deep requirements that are not available in many OS repositories. For RedHat and CentOS 7 users, I have have built RPMs and placed them on my Linux Yum Repository

To install the distribution with all dependencies - CentOS 7

  $ sudo yum install http://linux.davisnetworks.com/el7/updates/mrdvt92-release-8-2.el7.mrdvt92.noarch.rpm
  $ sudo yum install 'perl(Geo::H3)'

To install the additional dependencies for the example script perl-Geo-H3-geo-to-googleearth.pl

  $ sudo yum install 'perl(Geo::GoogleEarth::Pluggable)' 'perl(Geo::GoogleEarth::Pluggable::Plugin::Styles)' 'perl(Path::Class)'

AUTHOR

Michael R. Davis

COPYRIGHT AND LICENSE

MIT License

Copyright (c) 2021 Michael R. Davis

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.