public void Should_Give_Neighbors()
{
var hasher = new Geohasher();
var subhashes = hasher.GetNeighbors("u33dc0");
Assert.Equal("u33dc1", subhashes[Direction.North]);
Assert.Equal("u33dc3", subhashes[Direction.NorthEast]);
Assert.Equal("u33dc2", subhashes[Direction.East]);
Assert.Equal("u33d9r", subhashes[Direction.SouthEast]);
Assert.Equal("u33d9p", subhashes[Direction.South]);
Assert.Equal("u33d8z", subhashes[Direction.SouthWest]);
Assert.Equal("u33dbb", subhashes[Direction.West]);
Assert.Equal("u33dbc", subhashes[Direction.NorthWest]);
}
public void Should_Give_Neighbors_EdgeNorth()
{
var hasher = new Geohasher();
var subhashes = hasher.GetNeighbors("u");
Assert.Equal("h", subhashes[Direction.North]);
Assert.Equal("5", subhashes[Direction.NorthWest]);
Assert.Equal("j", subhashes[Direction.NorthEast]);
Assert.Equal("v", subhashes[Direction.East]);
Assert.Equal("s", subhashes[Direction.South]);
Assert.Equal("e", subhashes[Direction.SouthWest]);
Assert.Equal("t", subhashes[Direction.SouthEast]);
Assert.Equal("g", subhashes[Direction.West]);
}
public void Should_Give_Neighbors_EdgeWest()
{
var hasher = new Geohasher();
var subhashes = hasher.GetNeighbors("9");
Assert.Equal("c", subhashes[Direction.North]);
Assert.Equal("b", subhashes[Direction.NorthWest]);
Assert.Equal("f", subhashes[Direction.NorthEast]);
Assert.Equal("d", subhashes[Direction.East]);
Assert.Equal("3", subhashes[Direction.South]);
Assert.Equal("2", subhashes[Direction.SouthWest]);
Assert.Equal("6", subhashes[Direction.SouthEast]);
Assert.Equal("8", subhashes[Direction.West]);
}
public async Task <IEnumerable <string> > GetGeohashes(GeohashGetBinding binding)
{
var geohasher = new Geohasher();
using (var context = GetMainContext())
{
var neighbours = binding.Geohash is null ? null : geohasher.GetNeighbors(binding.Geohash);
return(await context.Trackings.WhereUser(UserId)
.WhereTimestampInclusive(binding)
.WhereIf(neighbours is not null, x => x.Geohash.StartsWith(binding.Geohash) ||
x.Geohash.StartsWith(neighbours[Direction.North]) ||
x.Geohash.StartsWith(neighbours[Direction.South]) ||
x.Geohash.StartsWith(neighbours[Direction.East]) ||
x.Geohash.StartsWith(neighbours[Direction.West]) ||
x.Geohash.StartsWith(neighbours[Direction.NorthEast]) ||
x.Geohash.StartsWith(neighbours[Direction.NorthWest]) ||
x.Geohash.StartsWith(neighbours[Direction.SouthEast]) ||
x.Geohash.StartsWith(neighbours[Direction.SouthWest]))
.Select(x => x.Geohash.Substring(0, binding.Precision))
.Distinct()
.ToListAsync());
}
}
public List <string> Neighbours(string geohash)
{
return(hasher.GetNeighbors(geohash).Select(d => d.Value).ToList());
}