README
¶
Region à gogo is a microservice, it's a simple database that returns metadata associated to a fence for a given location.
It uses S2 and a segment tree to create a fast geo shape database, details of implementation are described in this blog post.
It can also be used directly from docker docker run -P akhenakh/regionagogo
Data
You can use any geo data but the provided GeoJSON comes from Natural Earth Data. Some regions are not precise enough and some accentuated names are wrong, if you are aware of a better source please tell me.
It works too with the better Gadm Data but the data are not free for commercial use.
Regionagogo is using a BoltDB datafile to store the fences and a small segment tree as index lives in memory.
Build & Install
go get github.com/akhenakh/regionagogo
cd $GOPATH/src/github.com/akhenakh/regionagogo
make
To generate the database from GeoJSON use the provided ragogenfromjson command, you can specify the fields you want from the GeoJSON properties to be saved into the DB:
ragogenfromjson -filename testdata/world_states_10m.geojson -fields iso_a2,name -dbpath ./region.db
Usage
Run regionagogo -dbpath ./region.db, it will listen on port 8082.
You can query via HTTP GET:
GET /query?lat=19.542915&lng=-155.665857
{
"code": "US",
"name": "Hawaii"
}
Using it as a library
You can use it in your own code without the HTTP interface:
gs := regionagogo.NewGeoSearch("region.db")
r := gs.StabbingQuery(msg.Latitude, msg.Longitude)
TODO
- move the cache outside of boltdb storage to make it generic
- implement an in memory storage
Documentation
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Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func ImportGeoJSONFile ¶
func ImportGeoJSONFile(gs GeoFenceDB, r io.Reader, fields []string) error
ImportGeoJSONFile will load a geo json and save the polygons into the GeoFence for later lookup fields are the properties fields names you want to be associated with each fences
Types ¶
type Fence ¶
Fence is an s2 represented FenceStorage it contains an S2 loop and the associated metadata
func NewFenceFromStorage ¶
func NewFenceFromStorage(rs *geostore.FenceStorage) *Fence
NewFenceFromStorage returns a Fence from a FenceStorage Fence can be extended, FenceStorage is a protocol buffer instance
func (*Fence) ToGeoJSON ¶
func (f *Fence) ToGeoJSON() *geojson.FeatureCollection
ToGeoJSON transforms a Region to a valid GeoJSON
type Fences ¶
type Fences []*Fence
Fences a slice of *Fence (type used mainly to return one GeoJSON of the regions)
func (*Fences) ToGeoJSON ¶
func (f *Fences) ToGeoJSON() *geojson.FeatureCollection
ToGeoJSON transforms a set of Fences to a valid GeoJSON
type GeoFenceDB ¶
type GeoFenceDB interface {
// returns a Fence by it's storage id
FenceByID(loopID uint64) *Fence
// returns the fence for the corresponding lat, lng coordinates
StubbingQuery(lat, lng float64, opts ...QueryOptionsFunc) (Fences, error)
// RectQuery perform rectangular query ur upper right bl bottom left
RectQuery(urlat, urlng, bllat, bllng float64, opts ...QueryOptionsFunc) (Fences, error)
// RadiusQuery is performing a radius query
RadiusQuery(lat, lng, radius float64, opts ...QueryOptionsFunc) (Fences, error)
// Store a Fence into the DB
StoreFence(rs *geostore.FenceStorage, cover []uint64) error
// Close the DB
Close() error
}
GeoFenceDB is the main interface to store and query your geo database
type LoopFence ¶
LoopFence Making s2.Loop implements methods needed for coverage
func LoopFenceFromPoints ¶
LoopFenceFromPoints creates a LoopFence from a list of s2.Point
func (*LoopFence) ContainsCell ¶
ContainsCell checks whether the cell is completely enclosed by this loop. Does not count for loop interior and uses raycasting.
type QueryOptions ¶
type QueryOptions struct {
// Returns all fences when multiple fences match
MultipleFences bool
}
queryOptions used to pass options to DB queries
type QueryOptionsFunc ¶
type QueryOptionsFunc func(*QueryOptions)
func WithMultipleFences ¶
func WithMultipleFences(mf bool) QueryOptionsFunc
WithMultipleFences enable multi fences in responses
type S2Interval ¶
S2Interval is a CellID interval conforms augmentedtree Interval interface
func (*S2Interval) HighAtDimension ¶
func (s *S2Interval) HighAtDimension(d uint64) int64
HighAtDimension returns an integer representing the higher bound at the requested dimension.
func (*S2Interval) ID ¶
func (s *S2Interval) ID() uint64
ID should be a unique ID representing this interval. This is used to identify which interval to delete from the tree if there are duplicates.
func (*S2Interval) LowAtDimension ¶
func (s *S2Interval) LowAtDimension(d uint64) int64
LowAtDimension returns an integer representing the lower bound at the requested dimension.
func (*S2Interval) OverlapsAtDimension ¶
func (s *S2Interval) OverlapsAtDimension(iv augmentedtree.Interval, d uint64) bool
OverlapsAtDimension should return a bool indicating if the provided interval overlaps this interval at the dimension requested.
Source Files
Directories
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cmd
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db
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Package geostore is a generated protocol buffer package.
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Package geostore is a generated protocol buffer package. |