GeoSlick

Overview

GeoSlick is an experimental library that adds support for PostGIS to Slick

Geometry Columns

To support geometry columns have your tables mix in the Postgis trait or extend PostgisTable. To declare a geometry column you use the geoColumn method with the JTS type, field name and SRID:

def geom = geoColumn[Polygon]("geom", 4326)

Supported Features

Pretty much all PostGIS functions are supported except for PostGIS Geometry Editor extensions (http://postgis.refractions.net/documentation/manual-1.3/ch06.html#id2578062)

Example

import geoslick.PostgisDriver.simple._
import Database.threadLocalSession

object City extends Table[(Int,String,Geometry)]("cities") with Postgis {
      
  def id = column[Int]("id", O.PrimaryKey, O.AutoInc)
  def name = column[String]("name")
  def geom = geoColumn[Point]("geom", 4326)

  def * = id ~ name ~ geom
}

def fac() = new GeometryFactory(new PrecisionModel(), 4326)
def wkt[T <: Geometry](s: String) = new WKTReader(fac).read(s).asInstanceOf[T]

Database.forURL("jdbc:postgresql:slick",
                driver="org.postgresql.Driver",
                user="user", password="adam") withSession {

  City.ddl.create

  City.insert(1,"Philadelphia","POINT(-75.25 39.88)")
  City.insert(2,"Pittsburgh","POINT(-79.93 40.35)")

  val (n,g) = (for { c <- City if c.id === 2 } yield (c.name,c.geom)).first

  val q2 = for {
    c <- City if c.geom.distance(g) < 1.2
  } yield (c.name, c.geom, c.geom.distance(g))

  println(q2.selectStatement)

  q2 foreach {
    case (name, geom, d) => println("found: %s at %s (%f degs)" format (name, geom, d))
  }

  City.ddl.drop
               
}

Note that c.geom.distance(g) is turned into a PostGIS function. The select statement for q2 looks something like:

select x2."name", 
       ST_AsEWKB(x2."geom"), 
       ST_Distance(ST_AsEWKB(x2."geom"),
         ST_GeomFromEWKT('SRID=4326;POINT(-79.93 40.35)'))
from "cities" x2 
where ST_Distance(ST_AsEWKB(x2."geom"),
        ST_GeomFromEWKT('SRID=4326;POINT(-79.93 40.35)')) < 1.2