File: lib/Geo/H3.pm

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.

File: lib/Geo/H3/Index.pm

NAME

Geo::H3::Index - H3 Geospatial Hexagon Indexing System Index Object

SYNOPSIS

use Geo::H3::Index;
my $h3     = Geo::H3::Index->new(index=$index); #isa Geo::H3::Index
my $center = $h3->geo;                          #isa Geo::H3::GeoCoord
my $lat    = $center->lat;                      #isa double WGS-84 Decimal Degrees
my $lon    = $center->lon;                      #isa double WGS-84 Decimal Degrees

DESCRIPTION

H3 Geospatial Hexagon Indexing System Index Object provides the primary interface for working with H3 Indexes.

CONSTRUCTORS

new

my $geo = Geo::H3::Index->new(index=>$index);

PROPERTIES

index

Returns the H3 index uint64 representation

string

Returns the H3 string representation.

resolution

Returns the resolution of the index.

baseCell

Returns the base cell number of the index.

isValid

Returns non-zero if this is a valid H3 index.

isResClassIII

Returns non-zero if this index has a resolution with Class III orientation.

isPentagon

Returns non-zero if this index represents a pentagonal cell.

maxFaceCount

Returns the maximum number of icosahedron faces the given H3 index may intersect.

area

Returns the area in square meters of this index.

areaApprox

Returns the average area in square meters of indexes at this resolution.

edgeLength

Returns the exact edge length in meters of this index.

edgeLengthApprox

Returns the average edge length in meters of indexes at this resolution.

METHODS

geo

Returns the centroid of the index as a Geo::H3::Geo object.

geoBoundary

Returns the boundary of the index as a Geo::H3::GeoBoundary object

parent

Returns a parent index of this index as a Geo::H3::Index object.

my $parent = $h3->parent;    #next larger resolution
my $parent = $h3->parent(1); #isa Geo::H3::Index

children

Returns the children of the index as an array reference of Geo::H3::Index objects.

my $children = $h3->children(12); #isa ARRAY
my $children = $h3->children;     #next smaller resolution

centerChild

Returns the center child (finer) index contained by this index at given resolution.

my $centerChild = $index->centerChild;      #isa Geo::H3::Index
my $centerChild = $index->centerChild(12);  #isa Geo::H3::Index

kRing

Returns k-rings indexes within k distance of the origin index.

my $list $index->kRing($k); #isa ARRAY of L<Geo::H3::Index> objects

kRingDistances

Returns a hash reference where the keys are the H3 index and values are the k distance for the given index and k value.

my $hash = $index->kRingDistances($k);

hexRange

my $indexes = $index->hexRange($k);

hexRangeDistances

Returns a hash reference where the keys are the H3 index and values are the k distance for the given index and k value.

my $hash = $index->hexRangeDistances($k);

hexRing

Returns the hex ring of this index as an array reference of Geo::H3::Index objects

my $hexes = $h3->hexRing; #default k = 1
my $hexes = $h3->hexRing(5); #isa ARRAY

areNeighbors

Returns whether or not the provided H3Indexes are neighbors.

my $areNeighbors = $start_index->areNeighbors($end_index);

line

Returns the indexes starting at this index to the given end index as array reference of Geo::H3::Index objects.

my $list_aref = $start_index->line($end_index);

distance

Returns the distance in grid cells between this index to the given end index.

my $distance = $start_index->distance($end_index);

SEE ALSO

Geo::H3, Geo::H3::FFI

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.

File: lib/Geo/H3/Geo.pm

NAME

Geo::H3::Geo - H3 Geospatial Hexagon Indexing System Geo Object

SYNOPSIS

use Geo::H3::Geo;
my $geo    = Geo::H3::Geo->new(lat=>$lat, lon=>$lon); #isa Geo::H3::Geo
my $h3     = $geo->h3($resolution);                   #isa Geo::H3::Index
my $center = $h3->center;                             #isa Geo::H3::Geo
my $lat    = $center->lat;                            #isa double WGS-84 Decimal Degrees
my $lon    = $center->lon;                            #isa double WGS-84 Decimal Degrees

DESCRIPTION

H3 Geospatial Hexagon Indexing System Geo Object exposes the lat and lon properties as WGS-84 Decimal Degrees and converts coordinates to radians in the struct method for passing into theGeo::H3::FFI API as a Geo::H3::FFI::Struct::GeoCoord object.

The methods h3 and distance are wrappers around select Geo::H3::FFI methods.

CONSTRUCTORS

new

my $geo = Geo::H3::Geo->new(lat => $lat, lon => $lon);

PROPERTIES

lat

Returns the latitude in decimal degrees WGS-84

lon

Returns the longitude in decimal degrees WGS-84

METHODS

struct

Returns the Geo object as an FFI::C struct in the Geo::H3::FFI::Struct::GeoCoord namespace for use in the Geo::H3::FFI API.

h3

Indexes the location at the specified resolution, returning the index object Geo::H3::Index of the cell containing the location.

my $h3 = $geo->h3;    #default resolution is 0
my $h3 = $geo->h3(7); #isa Geo::H3::H3Index

Returns undef on error.

distance

Returns in meters the "great circle" or "haversine" distance between pairs of points (lat/lon pairs).

my $distance = $geoA->distance($geoB); #isa Double

SEE ALSO

Geo::H3, Geo::H3::FFI, Geo::H3::Index, Geo::H3::FFI::Struct::GeoCoord

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.

File: lib/Geo/H3/GeoBoundary.pm

NAME

Geo::H3::GeoBoundary - H3 Geospatial Hexagon Indexing System GeoBoundary Object

SYNOPSIS

use Geo::H3::GeoBoundary;
my $gb = Geo::H3::GeoBoundary->new(gb=>$gb); #isa Geo::H3::GeoBoundary
my $gb = Geo::H3::GeoBoundary->new(gb=>$gb, ffi=>$ffi); #isa Geo::H3::GeoBoundary

DESCRIPTION

H3 Geospatial Hexagon Indexing System GeoBoundary Object provides coordinates method to extract data from the FFI GeoBoundary object

CONSTRUCTORS

new

my $geo = Geo::H3::GeoBoundary->new(gb=>$gb);

PROPERTIES

gb

Returns the H3 GeoBoundary Object from the API as a Geo::H3::FFI::Struct::GeoBoundary object

METHODS

coordinates

Returns an OGC compatible closed polygon as an array reference of hashes i.e. [{lat=>$lat, lon=>$lon}, ...].

This coordinates format plugs directly into the format required for many Geo::GoogleEarth::Pluggable objects.

SEE ALSO

Geo::H3, Geo::H3::FFI::Struct::GeoBoundary, Geo::GoogleEarth::Pluggable

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.

File: scripts/perl-Geo-H3-geo-to-googleearth.pl

NAME

perl-Geo-H3-geo-to-googleearth.pl - Creates a Google Earth document from Coordinates, H3, Parent, Children and Hex Ring.

EXAMPLES

Default creates output.kmz

$ perl-Geo-H3-geo-to-googleearth.pl
Lat: 38.8894806546995
Lon: -77.0352387595358
Resolution: 8
Output: output.kmz
Format: kmz

KMZ output with defaults specified

$ perl-Geo-H3-geo-to-googleearth.pl --lat=38.889480654699476 --lon=-77.03523875953579 --resolution=8 --output=output.kmz
Lat: 38.889480654699476
Lon: -77.03523875953579
Resolution: 8
Output: output.kmz
Format: kmz

KML output pass a file name with "kml" extension.

$ perl-Geo-H3-geo-to-googleearth.pl --output=output.kml
Lat: 38.8894806546995
Lon: -77.0352387595358
Resolution: 8
Output: output.kml
Format: kml

SEE ALSO

Geo::GoogleEarth::Pluggable, Geo::GoogleEarth::Pluggable::Plugin::Styles, 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.