Purlin.Maps.Clustering 2.0.1

Purlin.Maps.Clustering

C# library for clustering map points for server side

Original Lib
This is a fork of GoogleMaps.AspNetCore.Clustering repo. The project was no longer powered since Jul 20, 2018.

Installation

You can download the Purlin.Maps.Clustering package to install the latest version of Purlin.Maps.Clustering Lib.

Features

1․ Server-side clustering

2․ K-nearest neighbors - (Haversine formula)

Usage

First, configure Program.cs class:

using Purlin.GoogleMaps.Clustering.Data.Configuration;
using Purlin.GoogleMaps.Clustering.Data.Params;
using Purlin.GoogleMaps.Clustering.Sample.Lib;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}
app.UseHttpsRedirection();


app.UseGmc(builder.Configuration.GetSection("GoogleMapsNetClustering"));

You will also need to add the following section to your appsettings.json file.

"GoogleMapsNetClustering": {
    "DoShowGridLinesInGoogleMap": false,
    "OuterGridExtend": 0,
    "DoUpdateAllCentroidsToNearestContainingPoint": false,
    "DoMergeGridIfCentroidsAreCloseToEachOther": true,
    "CacheServices": true,
    "MergeWithin": 2.9,
    "MinClusterSize": 2,
    "MaxMarkersReturned": 500,
    "AlwaysClusteringEnabledWhenZoomLevelLess": 2,
    "ZoomlevelClusterStop": 15,
    "GridX": 6,
    "GridY": 5,
    "MarkerTypes": [1,2,3],
    "MaxPointsInCache": 100000000
  },

Next, this is an example of how to used cached clustering.

public static class SampleCluster
{
    public static async Task<IList<MapPoint>> Clustering(GetMarkersParams markersParams = null!)
    {
        try
        {
            using var r = new StreamReader("path to file");
            var data = await r.ReadToEndAsync();
            var list = JsonSerializer.Deserialize<List<Point>>(data);

            var marker = GetClusters(list, markersParams);
            return marker;
        }
        catch
        {
            return new List<MapPoint>();
        }
    }

    private static IList<MapPoint> GetClusters(IEnumerable<Point> data, GetMarkersParams markersParams = null)
    {
        const string clusterPointsCacheKey = "somecachekey";
        var points = GetClusterPointCollection(data, clusterPointsCacheKey);

        var mapService = new ClusterService(points);

        var option = markersParams ?? new GetMarkersParams()
        {

            ZoomLevel = 6,
            PointType = clusterPointsCacheKey,
        };

        var markers = mapService.GetClusterMarkers(option);

        return markers.Markers;
    }

    private static PointCollection GetClusterPointCollection(IEnumerable<Point> data, string clusterPointsCacheKey)
    {
        var points = new PointCollection();

        var dbPoints = data.Select(p => new MapPoint
        {
            X = p.Lng!.Value,
            Y = p.Lat!.Value
        }).ToList();
        var cacheDuration = TimeSpan.FromHours(6);
        points.Set(dbPoints, cacheDuration, clusterPointsCacheKey);

        return points;
    }
}

public class Point
{
    public float? Lat { get; set; }
    public float? Lng { get; set; }
}