public ActionResult Search()
{
using (var context = new SpatialDemoContext())
{
dynamic viewModel = new ExpandoObject();
viewModel.MaxDistances = GetDistanceSelectList(5000);
viewModel.PostalCode = string.Empty;
viewModel.NeedsInitialization = GetNeedsInitialization(context);
viewModel.SearchFormTitle = "Search Places by Postal Code";
return View(viewModel);
}
}
public ActionResult List(string postalCode, int maxDistance)
{
using (var context = new SpatialDemoContext())
{
dynamic viewModel = new ExpandoObject();
// set up core viewmodel stuff for the view
viewModel.NeedsInitialization =
viewModel.PostalCode = postalCode;
viewModel.MaxDistance = maxDistance;
viewModel.MaxDistances = GetDistanceSelectList(maxDistance);
viewModel.NeedsInitialization = GetNeedsInitialization(context);
viewModel.SearchFormTitle = "Search Again";
// get the origin postal code from the database.
// we need this to get the lat/long/location of the origin postal code.
var startPoint = context.PostalCodes
.Where(p => p.Code == postalCode)
.FirstOrDefault();
// if no origin postal code was found, bail
if (startPoint == null)
{
viewModel.NoZipCode = true;
}
else
{
viewModel.NoZipCode = false;
var meters = maxDistance * MetersToMiles;
// do the search for places based on the origin's lat/long location,
// and select into a new viewmodel object ordered by distance
var results = context.Places
.Where(p => p.Location.Distance(startPoint.Location) <= meters)
.Select(p => new PlaceResult()
{
Name = p.Name,
Distance = (p.Location.Distance(startPoint.Location) / MetersToMiles).Value,
Latitude = p.Latitude,
Longitude = p.Longitude
})
.OrderBy(p => p.Distance)
.ToList();
viewModel.Results = results;
}
return View(viewModel);
}
}
public ActionResult Load()
{
// This is just a big parsing of two flat, tab-delimited files.
// It's just to get data into the database. Nothing fancy, but
// take note of the use of DbGeography and the POINT string to
// insert spatial geography types into the database.
using (var context = new SpatialDemoContext())
{
var stopwatch = new Stopwatch();
stopwatch.Start();
dynamic viewModel = new ExpandoObject();
if (context.PostalCodes.FirstOrDefault() != null)
{
viewModel.PostalCodesInserted = 0;
}
else
{
// load US postal codes
var path = Server.MapPath(UnitedStatesDataFile);
var lines = System.IO.File.ReadAllLines(path);
foreach (var line in lines)
{
var parts = line.Split(Tab);
var postalCode = new PostalCode()
{
Code = parts[1],
Latitude = double.Parse(parts[9]),
Longitude = double.Parse(parts[10])
};
// Here is where we set the SQL Geography spatial field
// on the Postal Code.
postalCode.Location = DbGeography.FromText(
string.Format(GetSqlPointString(postalCode.Latitude, postalCode.Longitude)));
context.PostalCodes.Add(postalCode);
}
viewModel.PostalCodesInserted = context.SaveChanges();
}
if (context.Places.FirstOrDefault() != null)
{
viewModel.PlacesInserted = 0;
}
else
{
// load places
var path = Server.MapPath(PlacesDataFile);
var lines = System.IO.File.ReadAllLines(path);
foreach (var line in lines)
{
var parts = line.Split(Tab);
var place = new Place()
{
Name = parts[0],
Latitude = double.Parse(parts[1]),
Longitude = double.Parse(parts[2])
};
// set the SQL Geography spatial field on the Place.
place.Location = DbGeography.FromText(
GetSqlPointString(place.Latitude, place.Longitude));
context.Places.Add(place);
}
viewModel.PlacesInserted = context.SaveChanges();
}
stopwatch.Stop();
viewModel.Elapsed = stopwatch.Elapsed.TotalSeconds;
return View(viewModel);
}
}
private bool GetNeedsInitialization(SpatialDemoContext context)
{
return context.Places.FirstOrDefault() == null
|| context.PostalCodes.FirstOrDefault() == null;
}
