teralytics / geohex

Geographical area hashing algorithms GeoHex and TeraHex

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GeoHex

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GeoHex implementation in Scala. Forked from geohex4j.

TeraHex

TeraHex is a geo-hashing scheme inspired by GeoHex with flexible grid sizes and encoders.

Usage on JVM

Add dependency to build.sbt:

resolvers += Resolver.bintrayRepo("teralytics", "maven")

libraryDependencies += "net.teralytics" %% "geohex" % "0.1.+"

Use functions of the net.teralytics.geohex.GeoHex object:

def encode(lat: Double, lon: Double, level: Int): String

def decode(code: String): Zone

def calcHexSize(level: Int): Double

Use functions of the net.teralytics.terahex.TeraHex object:

def zoneByLocation(loc: LatLon, level: Int): Zone

def encode(loc: LatLon, level: Int): Long

def decode(code: Long): Zone

def size(level: Int): Double

Usage in JavaScript

Install from NPM registry with:

$ npm install --save terahex

Or build using SBT with:

sbt geohexJS/fastOptJS

The resulting JavaScript file will be in js/target/scala-2.11/geohex-fastopt.js.

Use the functions of the terahex object:

function decode(code) // Returns Zone object

function encode(lon, lat, level) // Returns string code

function zoneByLocation(lon, lat, level) // Returns Zone object

function size(level) // Returns hexagon side length in degrees at a given level

function withRootSize(sizeAtLevelZero) // Returns a terahex object with a given root size

function zonesWithin(fromLon, fromLat, toLon, toLat, level) // Returns an array of Zones within the bounding box

The resulting Zone object has properties:

{
  "level": 3,
  "size": 12.345, // hexagon side length in degrees
  "location": { "lon": 0.00, "lat": 0.00 },
  "innerRadius": 11.222, // hexagon inner radius in degrees
  "geometry": [{"lon": 0.00, "lat": 0.00}, ... ], // locations of hexagon corners
  "wellKnownText": "POLYGON ((0.00 0.00, ...))", // hexagon geometry in WKT format
  "code": "1300251737352" // zone code as string
}

LICENSE

The MIT License (MIT)

Copyright (c) 2009 sa2da

Copyright (c) 2010 CHIKURA Shinsaku, Takuma Maruyama

Copyright (c) 2015 Teralytics AG

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.