P8m6E.png' alt='Update Marker Position Google Maps Api' title='Update Marker Position Google Maps Api' />Handling Large Amounts of Markers in Google Maps In usability we trust. To use markers in Google Maps is fairly trivial, at least when you have a reasonable amount of them. But once you have more than a few hundred of them, performance quickly starts to degrade. In this article I will show you a few approaches to speed up performance. Ive also put together a test page to compare them. Update 2. 00. 9 0. This article has been updated with the addition of the utility library Marker. Clusterer. The test results in the end of the article and the test page has also been revised. If youre new to markers in Google Maps I recommend that you first read Basic operations with markers in Google Maps for an introduction on how to use them. The Marker Manager Keeps track of them. Your first option might be to use the Marker. Manager since its an utility library provided by Google. Rather than adding each marker individually to the map using GMap. Overlay you first add them to the Marker. Manager. The Marker. Manager keeps track of all your markers. None of that counts mobile queries, where Google has a functional global monopoly with virtually no meaningful competition whatsoever. So few websavvy people seem to. In this article, we will develop an Android application which displays driving distance and travel time between two locations in Google Map Android API V2. By defining at which zoom levels each marker should appear you can cluster the markers to reduce the amount being shown at a time. The Marker. Manager is initially a bit slower than just adding markers directly to the map but the added benefit is that you can have more control over them. You add markers to the Marker. Manager with add. MarkerGMarker, min. Zoom, max. Zoom. This method takes three arguments, the first one being the marker you want to add. The two second arguments are optional but define at which zoom levels the marker will be visible. A simple example Create a new map. GMap. 2document. Element. By. Idmap. Centernew GLat. Lng5. Create a new instance of the Marker. Manager. var mgr new Marker. Managermap. Create a new marker. GMarkernew GLat. Lng5. Add marker to the Marker. Manager. mgr. add. Markermarker Obviously theres not much use adding a single marker to the Marker. Manager, but if you have hundreds of them, this might be the way to go. Jamie Shields walks through best practices for getting started with the Google Maps JavaScript API. Youre using lat and lng for the marker position before theyre initialized unless theyre globally set somewhere var newLatLng new google. LatLnglat, lng. Im using the Google Maps API to build a map full of markers, but I want one marker to stand out from the others. The simplest thing to do, I think, would be to. Google Maps . Y3tVE.jpg' alt='Update Marker Position Google Maps Api' title='Update Marker Position Google Maps Api' />Bulk adding the markers. An even more efficient way of using the Marker. Manager is to do a bulk add by first putting all your markers into an array and then add the array to the Marker. Manager with the add. Markersmarker. Array, min. Note that inialization code for map should go inside if IsPostBack block. Optionally you can specify which version of Google maps API to use. Leaflet Plugins. While Leaflet is meant to be as lightweight as possible, and focuses on a core set of features, an easy way to extend its functionality is to use. This is a great tutorial, for those who might want to skip the coding, there are also thirdparty services who utilize the Google Maps API as part of their offering. Zoom, max. Zoom method. Create a new instance of the Marker. Manager. var mgr new Marker. Managermap. Create marker array. DoGK1.png' alt='Update Marker Position Google Maps Api' title='Update Marker Position Google Maps Api' />Loop to create markers and adding them to the Marker. Manager. forvar i 0 i lt 5. GMarkernew GLat. Lng5. Add the array to the Marker. Manager. mgr. add. Markersmarkers. Refresh the Marker. Manager to make the markers appear on the map. Notice that you have to use mgr. Thats not necessary when adding the markers one by one. Additional methodsremove. MarkermarkerRemoves a marker from the Marker. Managerclear. MarkersRemoves all markers. Marker. CountzoomReturns the number of markers at a given zoom level. The Marker. Manager is a utility library provided by Google. On the URL below youll find the source code as well as the full documentation and examples. Google Maps Marker. Manager SVNMarker Light Markers on a diet. Pamela Fox at Google has made a sample app for what she calls Marker. Light, which render less complex markers, thus increasing performance. The trade off is that its really just an image on the map, you cant interact with it. If you dont have the need for interaction this is a really easy way to gain performance, the only difference from the ordinary way of doing it is that you create a Marker. Light instead of a GMarker. On Pamelas post about Marker. Light she explains why this approach is faster. The reason GMarker takes so long is that its actually composed of many DOM elements foreground, shadow, printable version, clickable area, etc. If your purpose is visualization, then you can get away with just creating a GOverlay extension like Marker. Light that creates a div with a background URL or background color, even better. Dibal Dld Software more. Pamela Fox. Heres how to use it map. Overlaynew Marker. Lightlatlng, image reddot. Its a very small and simple one. You can try performance with different numbers of markers on Pamelas test page. Download markerlight. Using Marker Light in combination with Marker. Manager. You can add the benefits of Marker. Light with the clustering capabilities of the Marker. Manager. Its really easy, just combine the two mgr. Markernew Marker. Lightlatlng, image reddot. The reason you should do this is that you can display a different number of markers at different zoom levels. This way you can ensure that not too many markers are displayed at the same time. Clusterer Only show what you need. A different approach is to use ACME labs Clusterer. Its a third party library that offers a faster way of adding markers. Its released under the BSD license and is freely available. It allows faster performance by doing two things. Only the markers currently visible actually get created. If too many markers would be visible, then they are grouped together into cluster markers. This lets you have literally thousands of markers on a map while maintaining decent performance. My tests with this approach shows that its significantly faster than the Marker. Manager approach. Heres how to use it Create a Clusterer object. Clusterermap. Create marker. GMarkernew GLat. Lng5. Add marker to the map. Add. Markermarker, text to infobox To remove a marker from the map call clusterer. Remove. Markermarker. Theres also a few methods to change the behavior of the marker. Set. IconGIconChanges the cluster iconclusterer. Set. Max. Visible. MarkersnSets the threshold marker count where clustering kicks in. Default value is 1. Set. Min. Markers. Per. ClusternSets the minumum number of markers for a cluster. Default value is 5. Set. Max. Lines. Per. Info. BoxnSets the maximum number of lines in an info box. Default value is 1. Download Clusterer. Cluster. Marker Chunk em all up. Cluster. Marker is a free Javascript library released under the GNU General Public License, that adds clustering capabilities to markers. The unique thing with this library is that it automatically detects markers that intersect each other and cluster these into a single cluster marker. The images below illustrates how this works. The constructor takes two arguments and looks like this var cluster new Cluster. Markermap, optionsmap is a reference to the map object and options is an object literal that can have these properties cluster. Marker. Icon GIconChanges the default cluster marker icon to an icon of your choice. An array with all the markers you want to pass to the Cluster. Marker. Apart from these properties you can also use all the other properties of the class. Se the documentation for a complete list. Heres how to add markers using the Cluster. Marker with a minimum amount of code. Array. Insert code to fill the marker. Array with markers. Creating a new cluster by adding the map and the markerarray. Cluster. Markermap, markers marker. Array. Refreshing to show the added markers. This code will insert the markers on the map and cluster them under one icon if theyre close enough to each other. For more fine grained control of how it operates there are several methods and properties. For a detailed explanation of how the library works theres excellent documentation on the Clustermarker Project page. Marker. Clusterer The new kid in town. GMap. NET Tutorial Maps, markers and polygons. The following is a tutorial for using the excellent GMap. NET control. This text will explain how to place a map control on a form, how to initialize it to show the coordinates you want, how to add markers to it, and how to add polygons. IMPORTANT You are currently reading our old tutorial. We a fresh GMap. NET tutorial about maps, markers, polygons and routes thats updated for Visual Studio 2. GMap. NET 1. 7 View the updated tutorialNote that we have more tutorials up on how to add routes to GMap. NET, calculating the area of a polygon in GMap. NET, and removing the red cross from a map in GMap. NET. Download the GMap. NET library here the so called hot build from 2. Setting up. First, create a new C Windows Forms project in Visual Studio 2. In your GMap. NET download, you will find DLLs named GMap. NET. Core. dll and GMap. NET. Windows. Forms. Place them in a subfolder of your project, and add a reference to both. This will allow your code to access GMap. NETs classes. Since GMap. NET is a user control, you can add it to your Toolbox. Of course, you could simply instantiate the GMap. Control from your code without ever adding it to your Toolbox, but then you would miss out on setting the controls properties conveniently through the Properties panel. To add the control to your Toolbox, right click the Toolbox and select Choose Items. Youll find the required assemblies by clicking Browse and selecting the GMap. NET. Windows. Forms DLL. This should contain the GMap. Control. Verify that theres a check next to this control, and when you click OK, the control should be in your Toolbox and can be dragged to a form. Adding a GMap to a Windows Form. Now add a new form your fresh C Windows Application should already have one and drag the GMap. Control to it. Resize it to your liking and call it gmap instead of the cumbersome GMap. Control. 1. The control will display as an empty rectangle With the control selected, open the Properties panel. Apart from the usual Control properties, youll find some GMap specific properties there. Now things will get interesting Ill explain some of the properties right away Can. Drag. Map If true, the user can drag the map using the right mouse button. Youll probably want to keep this set to true. Markers. Enabled If true, any markers that you defined will be shown. If not, they wont appear. Set this to true for now. If you forget, you may pull your hair out figuring out why your markers dont appear I did. Polygons. Enabled Same story here. Show. Tile. Grid. Lines If true, GMap. NET will show tile coordinates on the tiles. Not something for a production environment, but it may help with debugging. Zoom, Min. Zoom, Max. Zoom The Zoom level for Google Maps is somewhere between 0 zoomed out to global level to 1. Zoom is the current zoom level 5 would be good for country level, while Min. Zoom and Max. Zoom should be set to 0 and 1. Zooming is done with the mouse wheel. All these are interesting switches that allow us to define how the map will be shown and interacted with, but they dont allow us to set where the map data is coming from. As we will see, this must be done in code. Running the program now will result in a persistently blank rectangle where the map is supposed to go. Initializing the map. Add an on. Load event to your form, and add the following code to it. Form. 1Loadobject sender, Event. Args e. Initialize map. Map. Provider GMap. NET. Map. Providers. Bing. Map. Provider. Instance. GMap. NET. GMaps. Instance. Mode GMap. NET. Access. Mode. Server. Only. gmap. Set. Current. Position. By. KeywordsMaputo, Mozambique. Form. 1Loadobjectsender,Event. Argse   Initialize map  gmap. Map. ProviderGMap. NET. Map. Providers. Bing. Map. Provider. Instance  GMap. NET. GMaps. Instance. ModeGMap. NET. Access. Mode. Server. Only  gmap. Set. Current. Position. By. KeywordsMaputo, Mozambique. Now run the program. A map should appear, centered on the city of Maputo, Mozambique. Ive set the position using key words recognized by the map data provider, but you can also use latitudelongitude if you want. Position new Point. Lat. Lng 2. 5. 9. Positionnew. Point. Lat. Lng 2. 5. 9. While running the program, you will notice that the map can be dragged with the right mouse button, and zooming is done with the mouse wheel. If these operations do not work, then check that youve set the GMap. Controls properties correctly in the Properties panel you may have inadvertently turned off dragging, or fixed the zooming level. Map Providers. The magic of the GMap. NET library is that is doesnt merely work with Google Maps. There are other map data providers out there, and GMap. NET supports a slew of them while the gory API details are all neatly hidden away from you. In the example above, Ive used the Bing. Map. Provider, but other useful ones include Cloud. Made. Map. Provider. Google. Map. Provider map provider for Google Maps there are street, satellite and hybrid variants. Open. Cycle. Map. Provider. Open. Street. Map. Provider. Wiki. Mapia. Map. Provider. Yahoo. Map. Provider. Interestingly, the Google Map provider is for me, at least, the slowest one. The applications takes a good number of seconds to start, presumably because a connection with Google is being slowly made. The Bing Map provider was much faster. But, of course, the data shown will be different so it all depends on your preferences. At the very least, your map code could have fallback providers. Yahoo provider. Open Streetmap provider. Google provider. Bing provider. The magic of GMap. NET goes further still. When we get to showing markers and polygons on a map, well see that GMap. NET hides provider specific implementation details away behind a common interface. That means that any marker and polygon code you write for GMap. NET will work with any of the providers. Awesome Adding markers. Markers are added in layers that are placed on top of your map, called overlays. You can place any number of markers in an overlay, then add that overlay to the map. The overlay can then be hidden en shown as necessary. Here is a bit of code that adds an overlay called markers to the map, with a single marker in it. GMap. Overlay markers. Overlay new GMap. Overlaymarkers. GMarker. Google marker new GMarker. Googlenew Point. Lat. Lng 2. 5. 9. GMarker. Google. Type. Overlay. Markers. Addmarker. Overlays. Addmarkers. Overlay GMap. Overlay markers. Overlaynew. GMap. Overlaymarkers GMarker. Google markernew. GMarker. Googlenew. Point. Lat. Lng 2. GMarker. Google. Type. Overlay. Markers. Addmarker gmap. Overlays. Addmarkers. Overlay A Google type marker on a Bing Map provider. First, the overlay is created. You can give it a name optionally, which you can use elsewhere to refer to it or you could just keep a reference to the overlay instance. Next, an instance of GMarker. Google is created. It takes two arguments a location a Point. Lat. Lng instance and a marker type. The marker types are a variety of marker images normally available in the Google Maps API big balloons in many colors, small balloons in many colors, etc. Or, you can supply an instance of Bitmap with your own image. GMarker. Google marker new GMarker. Googlenew Point. Lat. Lng 2. 5. 9. Bitmapc imagesmymarker. GMarker. Google markernew. GMarker. Googlenew. Point. Lat. Lng 2. Bitmapc imagesmymarker.