Skip to main content

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

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 .

Bihar dials mobile tech to track road-building

         Upwardly mobile Bihar is now set to become the first state in India to use the latest cell phones for centralised monitoring of road construction. In an earlier post we saw how the Bihar police were using the GIS technology to track down the criminals.          Bihar State Road Development Corporation (BSRDC), under the Road Construction Department (RCD), will deploy Android phones to help executive engineers keep an eye on road construction from district headquarters, while the RCD Secretary will do so from the Patna office.          Earlier, Bihar State Bridge Construction Corporation had successfully used GPS-enabled phones to help mobile inspectors track engineers on duty. The latest mobile operation system supports all Google applications in 3G mobile phones.          Using the latest Android technology, ...

Blue census, Water census...

          The Uttar Pradesh State Water and Sanitation Mission (SWSM) will soon be documenting the drinking water resources across six zones of the state. These zones are Allahabad, Ghaziabad, Gorakhpur, Lucknow, Varanasi and Moradabad. The documentation - to be done through Geographical Information System (GIS) and Global Positioning System (GPS) mapping - will take note of ponds (manmade and natural), wells and handpumps. This exercise which is a part of the National Rural Drinking Water Programme (NRDWP) will help the officials to create a proper database of these resources, which will be used for their management.          Through the mapping, all the details of all the resources will be compiled, complete with their longitude and latitude dimensions. The department plans to start off the exercise by April 1, 2011 and should end by March 31, 2012. The focus will initially be on villages where the ...

Jugnu: India's first Nano Satellite

          IIT-Kanpur with its nano satellite 'Jugnu' has set new highs in the field of space research. A team of students, working under Dr NS Vyas (the visionary man behind the making of the nano-satellite) and other faculty members of the institute, have successfully made the country's first nano-satellite to be developed for the first time by any educational institute.           The development of the Jugnu started in the year 2008 with a team of 3 students. With time, the team has grown to the size of more than 50 students ranging from 1st year undergraduates to final year postgraduates and 14 professors from different disciplines to complete this challenging mission.            The satellite has been handed over to two ISRO scientists, DVA Raghav Murthy (Project Director, Small Satellite Projects) and Dr SK Shiv Kumar (Director, ISRO sat...

Form info window

         Today we will look at a Google Maps API v3 example to add a form in the information bubble! This is usually required when we wish to accept some data/information from the user! This data can be saved to a server in the form of an XML file or a database! The information can then be retrieved back at a later stage, when necessary!          In this example we will only look at form in the information bubble! The connectivity part with the server will be discussed in another post! So, today's code snippet is as seen below! <html> <head> <title> Google Maps API v3 - Adding marker and info window on Click and creating a form in the infowindow with the lat-lng information in it. </title> <script type="text/javascript" src="http://maps.google.com/maps/api/js?sensor=false"></script> <script type="text/javascript"> var map;    //When using ev...