dyngeo

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 Go to latest Published: Dec 9, 2020 License: MIT Imports: 12 Imported by: 1

README

DynG(e)o

Unofficial Go port of the Geo Library for Amazon DynamoDB using geohash to easily create and query geospatial data. The library takes care of managing the geohash indexes and storing item with latitude/longitude pairs.

Install

Fetch the package with

go get github.com/crolly/dyngeo

And import it into your programs with

import "github.com/crolly/dyngeo"

Usage

DynG(e)o Configuration
type DynGeoConfig struct {
	TableName             string
	ConsistentRead        bool
	HashKeyAttributeName  string
	RangeKeyAttributeName string
	GeoHashAttributeName  string
	GeoJSONAttributeName  string
	GeoHashIndexName      string
	HashKeyLength         int8
	LongitudeFirst        bool

	DynamoDBClient  *dynamodb.DynamoDB
}

Defines, how DynG(e)o manages the geospatial data, e.g. what the db attribute and index names are as well as setting the geohash key length. The geohash key length will determine the size of the tiles the planet will be seperated into:

Length Tile Size
1 5,009.4km x 4,992.6km
2 1,252.3km x 624.1km
3 156.5km x 156km
4 39.1km x 19.5km
5 4.9km x 4.9km
6 1.2km x 609.4m
7 152.9m x 152.4m
8 38.2m x 19m
9 4.8m x 4.8m
10 1.2m x 59.5cm
11 14.9cm x 14.9cm
12 3.7cm x 1.9cm

Setting DynamoDBClient *dynamodb.DynamoDB and TableName string is required.

DynG(e)o Instance
func New
func New(config DynGeoConfig) (*DynGeo, error)

Returns a new instance of DynG(e)o managing the geohashing and geospatial db operations.

func PutPoint
func (dg DynGeo) PutPoint(input PutPointInput) (*PutPointOutput, error)

Put a point into the Amazon DynamoDB table. Once put, you cannot update attributes specified in GeoDataManagerConfiguration: hash key, range key, geohash and geoJson. If you want to update these columns, you need to insert a new record and delete the old record.

func BatchWritePoints
func (dg DynGeo) BatchWritePoints(inputs []PutPointInput) (*BatchWritePointOutput, error)

Put a list of points into the Amazon DynamoDB table. Once put, you cannot update attributes specified in GeoDataManagerConfiguration: hash key, range key, geohash and geoJson. If you want to update these columns, you need to insert a new record and delete the old record.

func GetPoint
func (dg DynGeo) GetPoint(input GetPointInput) (*GetPointOutput, error)

Get a point from the Amazon DynamoDB table.

func UpdatePoint
func (dg DynGeo) UpdatePoint(input UpdatePointInput) (*UpdatePointOutput, error)

Update a point data in Amazon DynamoDB table. You cannot update attributes specified in GeoDataManagerConfiguration: hash key, range key, geohash and geoJson. If you want to update these columns, you need to insert a new record and delete the old record.

func DeletePoint
func (dg DynGeo) DeletePoint(input DeletePointInput) (*DeletePointOutput, error)

Delete a point from the Amazon DynamoDB table.

func QueryRadius
func (dg DynGeo) QueryRadius(input QueryRadiusInput, out interface{}) error

Query a circular area constructed by a center point and its radius.

func QueryRectangle
func (dg DynGeo) QueryRectangle(input QueryRectangleInput, out interface{}) error

Query a rectangular area constructed by two points and return all points within the area. Two points need to construct a rectangle from minimum and maximum latitudes and longitudes. If minPoint.Longitude > maxPoint.Longitude, the rectangle spans the 180 degree longitude line.

Getting Started Example

This repository contains a Getting Started example in the folder starbucks-example inspired by James Beswick's very good blog post about Location-based search results with DynamoDB and Geohash

It uses the US Starbucks locations, loads them into DynamoDB in batches of 25 and then retrieves the the locations of all Starbucks in the radius of 5000 meters surrounding Latitude: 40.7769099, Longitude: -73.9822532.

The example illustrates the general usage as well as a hint of the performance. The radius search constantly needs about 20-30ms with the given dataset (approximately 6500 Starbucks coffee shops in the US).

Documentation

Index

Constants

View Source 
const EARTH_RADIUS_METERS = 6367000.0

S2 Util

View Source 
const MERGE_THRESHOLD = 2

MERGE_THRESHOLD ...

Variables

This section is empty.

Functions

func GetCreateTableRequest 

func GetCreateTableRequest(config DynGeoConfig) *dynamodb.CreateTableInput

Types

type BatchWritePointOutput 

type BatchWritePointOutput struct {
	*dynamodb.BatchWriteItemOutput
}

type DeletePointInput 

type DeletePointInput struct {
	PointInput
	DeleteItemInput dynamodb.DeleteItemInput
}

type DeletePointOutput 

type DeletePointOutput struct {
	*dynamodb.DeleteItemOutput
}

type DynGeo 

type DynGeo struct {
	Config DynGeoConfig
	// contains filtered or unexported fields
}

func New 

func New(config DynGeoConfig) (*DynGeo, error)

NewDynGeo ...

func (DynGeo) BatchWritePoints 

func (dg DynGeo) BatchWritePoints(inputs []PutPointInput) (*BatchWritePointOutput, error)

func (DynGeo) BatchWritePointsWithContext 

func (dg DynGeo) BatchWritePointsWithContext(ctx context.Context, inputs []PutPointInput) (*BatchWritePointOutput, error)

func (DynGeo) DeletePoint 

func (dg DynGeo) DeletePoint(input DeletePointInput) (*DeletePointOutput, error)

func (DynGeo) DeletePointWithContext 

func (dg DynGeo) DeletePointWithContext(ctx context.Context, input DeletePointInput) (*DeletePointOutput, error)

func (DynGeo) GetPoint 

func (dg DynGeo) GetPoint(input GetPointInput) (*GetPointOutput, error)

func (DynGeo) GetPointWithContext 

func (dg DynGeo) GetPointWithContext(ctx context.Context, input GetPointInput) (*GetPointOutput, error)

func (DynGeo) PutPoint 

func (dg DynGeo) PutPoint(input PutPointInput) (*PutPointOutput, error)

func (DynGeo) PutPointWithContext 

func (dg DynGeo) PutPointWithContext(ctx context.Context, input PutPointInput) (*PutPointOutput, error)

func (DynGeo) QueryRadius 

func (dg DynGeo) QueryRadius(input QueryRadiusInput, out interface{}) error

func (DynGeo) QueryRadiusWithContext 

func (dg DynGeo) QueryRadiusWithContext(ctx context.Context, input QueryRadiusInput, out interface{}) error

func (DynGeo) QueryRectangle 

func (dg DynGeo) QueryRectangle(input QueryRectangleInput, out interface{}) error

func (DynGeo) QueryRectangleWithContext 

func (dg DynGeo) QueryRectangleWithContext(ctx context.Context, input QueryRectangleInput, out interface{}) error

func (DynGeo) UpdatePoint 

func (dg DynGeo) UpdatePoint(input UpdatePointInput) (*UpdatePointOutput, error)

func (DynGeo) UpdatePointWithContext 

func (dg DynGeo) UpdatePointWithContext(ctx context.Context, input UpdatePointInput) (*UpdatePointOutput, error)

type DynGeoConfig 

type DynGeoConfig struct {
	TableName             string
	ConsistentRead        bool
	HashKeyAttributeName  string
	RangeKeyAttributeName string
	GeoHashAttributeName  string
	GeoJSONAttributeName  string
	GeoHashIndexName      string
	HashKeyLength         int8
	LongitudeFirst        bool

	DynamoDBClient *dynamodb.DynamoDB
	// contains filtered or unexported fields
}

type GeoJSONAttribute 

type GeoJSONAttribute struct {
	Type        string    `json:"type"`
	Coordinates []float64 `json:"coordinates"`
}

type GeoPoint 

type GeoPoint struct {
	Latitude  float64
	Longitude float64
}

type GeoQueryInput 

type GeoQueryInput struct {
	QueryInput dynamodb.QueryInput
}

type GeoQueryOutput 

type GeoQueryOutput struct {
	*dynamodb.QueryOutput
}

type GetPointInput 

type GetPointInput struct {
	PointInput
	GetItemInput dynamodb.GetItemInput
}

type GetPointOutput 

type GetPointOutput struct {
	*dynamodb.GetItemOutput
}

type PointInput 

type PointInput struct {
	RangeKeyValue string
	GeoPoint      GeoPoint
}

type PutPointInput 

type PutPointInput struct {
	PointInput
	PutItemInput dynamodb.PutItemInput
}

type PutPointOutput 

type PutPointOutput struct {
	*dynamodb.PutItemOutput
}

type QueryRadiusInput 

type QueryRadiusInput struct {
	GeoQueryInput
	CenterPoint   GeoPoint
	RadiusInMeter int
}

type QueryRadiusOutput 

type QueryRadiusOutput struct {
	*GeoQueryOutput
}

type QueryRectangleInput 

type QueryRectangleInput struct {
	GeoQueryInput
	MinPoint *GeoPoint
	MaxPoint *GeoPoint
}

type QueryRectangleOutput 

type QueryRectangleOutput struct {
	*GeoQueryOutput
}

type UpdatePointInput 

type UpdatePointInput struct {
	PointInput
	UpdateItemInput dynamodb.UpdateItemInput
}

type UpdatePointOutput 

type UpdatePointOutput struct {
	*dynamodb.UpdateItemOutput
}

Source Files

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