public void TestSTDistance()
{
using (var db = new PostGisTestDataConnection(TestDatabaseConnectionString))
{
var point = new NTSGS.Point(new NTSGS.Coordinate(-72.1235, 42.3521))
{
SRID = SRID4326
};
db.Insert(new TestGeometryEntity(1, point));
var lineString = new NTSGS.LineString(new[] { new NTSGS.Coordinate(-72.1260, 42.45), new NTSGS.Coordinate(-72.123, 42.1546) })
{
SRID = SRID4326
};
db.Insert(new TestGeometryEntity(2, lineString));
// Geometry example - units in planar degrees 4326 is WGS 84 long lat, units are degrees.
var distances4326 = db.TestGeometries
.Select(g => g.Geometry.STDistance(point))
.ToList();
Assert.AreEqual(2, distances4326.Count);
Assert.AreEqual(0.0, distances4326[0]);
Assert.AreEqual(0.00150567726382822, distances4326[1].Value, 1.0E-9);
// Geometry example - units in meters (SRID:3857, proportional to pixels on popular web maps).
var distances3857 = db.TestGeometries
.Select(g => g.Geometry.STTransform(SRID3857).STDistance(point.STTransform(SRID3857)))
.ToList();
Assert.AreEqual(2, distances3857.Count);
Assert.AreEqual(0.0, distances3857[0]);
Assert.AreEqual(167.441410065196, distances3857[1].Value, 1.0E-9);
var nullDistance = db.TestGeometries
.Where(g => g.Id == 1)
.Select(g => g.Geometry.STDistance(null))
.Single();
Assert.IsNull(nullDistance);
Assert.AreEqual(
0.00150567726382282,
db.Select(() => MeasurementFunctions.STDistance(
"SRID=4326;POINT(-72.1235 42.3521)",
"SRID=4326;LINESTRING(-72.1260 42.45, -72.123 42.1546)")).Value,
1.0E-12);
Assert.IsNull(db.Select(() => MeasurementFunctions.STDistance((NTSG)null, (NTSG)null)));
// geography
var pointGeography = new NTSGS.Point(-72.1235, 42.3521)
{
SRID = SRID4326
};
db.Insert(new TestGeographyEntity(1, pointGeography));
var lineGeography = new NTSGS.LineString(new[] { new NTSGS.Coordinate(-72.1260, 42.45), new NTSGS.Coordinate(-72.123, 42.1546) })
{
SRID = SRID4326
};
db.Insert(new TestGeographyEntity(2, lineGeography));
var distance1 = db.TestGeographies
.Where(g => g.Id == 1)
.Select(g => g.Geography.STDistance(db.TestGeographies.Where(g0 => g0.Id == 2).Single().Geography))
.Single();
Assert.AreEqual(123.802077, distance1.Value, 1.0E-6);
var distance2 = db.TestGeographies
.Where(g => g.Id == 1)
.Select(g => g.Geography.STDistance(db.TestGeographies.Where(g0 => g0.Id == 2).Single().Geography, false))
.Single();
Assert.AreEqual(123.475737, distance2.Value, 1.0E-6);
}
}
