novotnyllc / s2-geometry-library-csharp Goto Github PK

can i use this library to have several grids and query the cell values at some latitude and longitude? for example i want to know at position X the value of the cell that goes from 0 to 5 for how dangerous is that cell and another grid that goes from 0 to 200 for the max speed alowed if it is a street or highway or else.

I am trying to get the level 10 cell ID for central Manchester.

Google says its coordinate is 53.479683, -2.242776. So i tried it like that:
S2LatLng ll = S2LatLng.FromDegrees(53.479683, -2.242776);
But now if i try to get the ID like this:
S2CellId.FromLatLng(ll).Id.ToString();
It returns the wrong cell ID and
S2CellId.FromLatLng(ll).Level
is always level 30 without any chance of choosing it. How can i set the S2 cell level i like and get the right cell ID?

I occasionally get the following exception when getting a covering for a large area. It sometimes succeeds (guessing 10-20% of the time in this case, however it seems to be random). This doesn't seem to happen with lower level's like 10.

Error:
Additional information: The runtime has encountered a fatal error. The address of the error was at 0x705fe24f, on thread 0x2dc0. The error code is 0xc0000005. This error may be a bug in the CLR or in the unsafe or non-verifiable portions of user code. Common sources of this bug include user marshaling errors for COM-interop or PInvoke, which may corrupt the stack.

Code to reproduce:

using System.Collections.Generic;
using Google.Common.Geometry;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            var region_rect = S2LatLngRect.FromPointPair(S2LatLng.FromRadians(0.733204387077201, -1.99196858250162), S2LatLng.FromRadians(0.567830031749048, -2.17145323019111));
            var coverer = new S2RegionCoverer()
            {
                MaxLevel = 13,
                MinLevel = 13
            };
            var covering = new List<S2CellId>();
            coverer.GetCovering(region_rect, covering);
        }    
    }
}

C5 has a known issue that prevents it from compiling with .NET Native due to infinite expansion.

I suggest you use native .NET collections in place of C5. I used HashSet and Dictionary in place of HashBag and HashDictionary and the library appears to work correctly.

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I need to extract Lat/Lng coordinates from a given CellId, but I'm having a slight difference netween the returned values and the correct ones, and I can't understand why.

The original coordinates are

47.678956162876,-122.12871664749933

while the CellId is

6093384589483442176

What I get back is

47.72217122031298,-122.12705319813203

Here's a little snippet of my code:

var cellId = new S2CellId(CellId).ToLatLng();            
return new Geopoint(new BasicGeoposition() {Latitude = cellId.LatDegrees, Longitude = cellId.LngDegrees})

Am I doing something wrong or is there an issue when converting back to Lat/Lng?