GoogleMaps.Net.Clustering

C# library for clustering map points. This library is very suitable for WebAPI (and similar-type) projects that don't depend on ASP.Net MVC.

Original Lib
This is a fork of Google Maps Server-side Clustering with C# repo. The guys made a fast, working implementation of Google Maps clustering for C#. However, they tightly coupled it with MVC and WebForms where all I needed was a simple C# way to crunch a bunch of simple map points and convert them into cluster points.

Installation
You can download the GoogleMaps.Net.Clustering package to install the latest version of GoogleMaps.Net.Clustering Lib.

Sponsored by Dovetail Technologies.

Usage

This is an example of how to used cached clustering.

public IList<MapPoint> GetClusters(YourFilterObj filter)
{
    var clusterPointsCacheKey = "somecachekey";
    var points = GetClusterPointCollection(clusterPointsCacheKey);

    var mapService = new ClusterService(points);
    var input = new GetMarkersParams()
    {
        NorthEastLatitude = filter.NorthEastLatitude,
        NorthEastLongitude = filter.NorthEastLongitude,
        SouthWestLatitude = filter.SouthWestLatitude,
        SouthWestLongitude = filter.SouthWestLongitude,
        ZoomLevel = filter.ZoomLevel,
        PointType = clusterPointsCacheKey
    };

    var markers = mapService.GetClusterMarkers(input);

    return markers.Markers;
}

private PointCollection GetClusterPointCollection(string clusterPointsCacheKey)
{
    var points = new PointCollection();
    if (points.Exists(clusterPointsCacheKey))
        return points;

    var dbPoints = GetPoints(); // Get your points here
    var mapPoints = dbPoints.Select(p => new MapPoint() { X = p.X, Y = p.Y }).ToList();
    var cacheDuration = TimeSpan.FromHours(6);
    points.Set(mapPoints, cacheDuration, clusterPointsCacheKey);

    return points;
}

You will also need to add the following section to your .conf file (add it before the connectionString and/or appSettings section).

<googleMapsNetClustering>
    <!-- Configuration data for clustering, separate file to make the web.config file cleaner -->
    <!-- Read GmcSettings.cs for description -->
    <!-- debug purpose -->
    <add key="DoShowGridLinesInGoogleMap" value="false" />
    <!-- if bigger value then more expensive -->
    <add key="OuterGridExtend" value="0" />
    <!-- if true, then more expensive -->
    <add key="DoUpdateAllCentroidsToNearestContainingPoint" value="false" />
    <add key="DoMergeGridIfCentroidsAreCloseToEachOther" value="true" />
    <!-- cache get markers and get marker info services -->
    <add key="CacheServices" value="true" />
    <!--heuristic value for when to merge clusters when close to each other -->
    <add key="MergeWithin" value="2.9" />
    <add key="MinClusterSize" value="2" />
    <!-- restrict json length for client -->
    <add key="MaxMarkersReturned" value="500" />
    <!-- server-side control, set to -1 for disabled -->
    <add key="AlwaysClusteringEnabledWhenZoomLevelLess" value="2" />
    <add key="ZoomlevelClusterStop" value="15" />
    <add key="GridX" value="6" />
    <add key="GridY" value="5" />
    <add key="MarkerTypes" value="1;2;3" />
    <add key="MaxPointsInCache" value="100000000" />
</googleMapsNetClustering>