Removing overlays

    "Overlays"....!!! What is this now! Never heard or used it before? You might immediately say "NO"...But, actually all of you have already seen what an overlay is and you have also used it! Now you would say "When!?!?" Well, all of the markers, polylines, polygons that you have created are overlays. Overlays are objects on the map that are tied to latitude/ longitude coordinates, so they move when you drag or zoom the map. Overlays reflect objects that you add to the map to designate points, lines, areas or collection of objects.

    Till now we have seen how to create an overlay. In today's example we will see how to remove an overlay. In this example we will create markers on click. But the difference will be that when you create a new marker, the earlier one will disappear from the map. So at any given time there would only be one single marker on the map! Note that removing the marker does not delete the overlay; it simply removes the overlay from the map.

    Let's head on to the example. You can copy the following code in a text file and save it with .html extension. Now click on this file and it will open up in your default browser and you will see the map in action!

    The code is very simple. You should have no problems in understanding the same. If you have any queries or doubts regarding the code, you can leave a comment or drop me a mail. The output of the above example is as seen in the result section above.

Comments

Recommended for You

Where does Google get it's live traffic data from?

Referring to a post that I wrote earlier, Google’s - Live traffic Layer , ever wondered how Google collected this data? I was wondering the other day, how Google received live data to display it on their maps as a layer! I looked up the web and found something very interesting and am sharing the same with you all. As we all know, the traffic layer is available most accurately in several states in USA. Most major metro areas in the US have sensors embedded in their highways. These sensors track real time traffic data. Easy to miss at high speeds (hopefully anyway, traffic permitting), more commonly noticed may be the similar sensors that often exist at many busy intersections that help the traffic lights most efficiently let the most amount of people through. The information from these tracking sensors is reported back to the Department of Transportation (DOT). The DOT uses this data to update some of the digital signs that report traffic conditions in many metro areas. They als

Geodesic Polyline

Today we will have a look at a very interesting polyline example - "The geodesic polyline". Now the first question that will pop is "What is geodesic?". Mathematically, geodesic means the shortest line between two points on a mathematically defined surface, as a straight line on a plain or an arc of a great circle or sphere. The next question after reading the above definition is clearly, "Why do we need geodesic polylines?" and that would be followed up with "What is this Great Circle?". We will discuss this first, before we move on to the actual example today. The example is very very similar to the normal polyline example, with just a small change. Having said so, I will now try to explain why we need a geodesic polyline? The shortest distance between two locations on the earth is rarely a straight line as the earth is roughly spherical in nature. So any two points on the earth, even if they are very close lie on a curve and n

GIS Technology to identify all properties in BBMP Limits

The Bruhat Bangalore Mahanagara Palike (BBMP) has for the last two years, been in the process of conducting a massive exercise to map the 13.87 lakh properties in the 198 wards in the city. Geographical Information System (GIS) has proven to be an effective tool for analysing and displaying thematic maps of all the roads for proper evaluation and correction of zones. As of now, 11 lakh properties have come under the tax net. The aim of this programme, which is perhaps the first such exercise being conducted in the country on such a large scale, covering 800 square km, is to bring all properties under the tax net and ensure that the BBMP has accurate information pertaining to the properties’ dimension, built-up area, land use and classification. The process of validation of GIS maps will be completed in January 2011. The process uses satellite digital maps of the BBMP area to generate a vector map from the information obtained. These high r

Playing with the markers and info window bubbles...

In the last few posts, we have seen some marker examples and some information window examples. Now, lets do something interesting combining these two things. Just writing that "This is an info window" in the information bubble is not very interesting! And I know this...Have gone through the same phase! So, today we will do something interesting! We will display the latitude- longitude co-ordinates of the point that the user clicks on the map! Doing this is not at all complex! Copy paste the following code and you will see for yourself a map coming to life! The output of the above code looks as seen in the result section above! If you have any queries regarding the above code please comment on the blog post or feel free to contact me at my mail ID .

Google Street View Image API

Street View is one of most used feature of the Google Maps and why not? You can actually see any part of the world as if you are visiting the place at that very moment. And now with the Google Street View Image API, you don't even need to carry a camera with you to the places you visit. You can take-in all the scenic beauty without even bothering about clicking a single picture. You can come back from your vacation and get a few images using the Google Street View Image API and show those images to your friends and relatives. Create an album of high definition images and go ahead and share it on Facebook for your friends to have a look. Using the Google Street View Image API is very simple and anybody can make use of it without any programming knowledge required. I will walk you through the entire process of effectively using the Google Street View Image API. So if you are set, let's go on an amazing ride across the globe with the Google Street Views. The Go

The UI Dev

Search This Blog