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Showing posts from January, 2011

ES6 101 - Map

ES6 101 - Map
ES6 Map is the topic of today’s post which also is the 11th in the ES6 101 Series. Map is going to be fairly easy, so before jumping into it, if you want to look at other features we have covered so far, here is a quick list for your reference.Fat Arrow FunctionsLexical Declarations - LetLexical Declarations - ConstSpread OPeratorTemplate LiteralRest OperatorDefault parametersDestructuringFor…ofSetNow let’s see what Map has to offer. As opposed to Set (which by the way, I highly recommend reading), Map saves values as key-value pair. Let’s see for ourselves how this works!Example of ES6 Mapvar dummyMap = newMap(); dummyMap.set("1"); // Method is set as against add in ES6 Setconsole.log(dummyMap); // [["1",null]] dummyMap.set("1", "one"); console.log(dummyMap); // [["1","one"]] dummyMap.set("2", "two").set("3","three"); console.log(dummyMap); // [["1","one&…

Follow Your World!

Google now offers you a simple application that informs you by email each time we update the satellite and aerial imagery in your area of interest. Follow Your World is a free service that allows you to enter the lat/long of a location along with your email address. Whenever any imagery is updated for that location, an email alert will be sent.
         Our surroundings are constantly changing, so it's no surprise that Google Earth and Google Maps users often request the most up-to-date satellite and aerial imagery. While Google can't necessarily update the world's imagery in real-time, they can let you know when they do update this imagery.
         In just three easy steps, you can add points such as your hometown, your college, or just about any place on the Earth.
Step 1. Find a location. Search for the area by entering the name of a country, state, city, or a specific address. You can also enter the exact latitude/longitude of the location. Click Search Locat…

Overlays - A complex example

In the last post we have seen what an overlay is and we have also seen a small simple overlay example as well. Today's example is a bit complex as compared to the last one, but is not at all difficult. We will directly jump to the code instead of having any more descriptions and stuff. So, here's the code.

    The output of the above code looks as seen in the result section above. You need to click on the map to place a marker on the map. You can place multiple markers on the map by clicking on the map multiple times. By clicking on the "Clear overlays" button all the markers on the map will disappear. By clicking on the "Show all overlays" button, all the cleared, but not deleted markers will reappear. Clicking on the "Delete overlays" buttons will remove all the markers permanently.

    If you have any doubts or queries regarding the code please leave a comment or drop me a mail.

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 …

India celebrates 62nd Republic Day

India celebrates it's 62nd Republic day today! Wish you all a happy Republic Day!

Mumbai Metro to implement GIS

Mumbai's Metro rail system, which is scheduled to take off by next year, will have a Geographic Information System (GIS) for mapping the entire rail tracks and nearby areas to enhance safety, maintenance and traffic regulation.
Mumbai Metro One Pvt. Ltd. (MMOPL) - the special purpose vehicle promoted by Reliance Infrastructure, Mumbai Metropolitan Region Development Authority (MMRDA) and French multinational firm Veolia - is implementing the GIS along the Versova-Andheri-Ghatkopar (VAG) corridor in Phase-I of the project. This is a first-of-its-kind initiative in the country for Metro rail management.

          The GIS system will map the exact location of the trains and all emergency services, including fire stations, police stations and hospitals along the alignment. In case there is a fire incident or other emergencies, the exact location of the nearest fire station or police station can be identified with the help of the GIS map to ensure speedy response…

Geodesic, Draggable Onclick Polygon

After creating a simple polygon and then creating an on-click polygon, we will today see how to create a polygon which can be changed, altered, dragged; basically edited on the fly. We will also cover the geodesic polygon in this example itself. If you want to read and understand more about what "geodesic" is, read this post.

    Nothing exceptional about the code that I think needs explanation! You can create a geodesic polygon which can be edited on the fly. Click, hold and drag any marker, and the two polylines connected by this marker will change accordingly. By clicking on the marker, that marker would disappear, and the polygon will reform itself! Here is today's code.

    You can copy the above code in a text file and save it with .html extension. Click on this file; it will open in your default browser and you will see an exciting map in action! The output of the above code appears as seen in the result section above! If you have any doubts or queries regard…

Onclick polygon

Yesterday we had a look at a simple polygon example. But that example was not exciting as it was all hard-coded with no user interaction and which means no fun! Today's example will deal with creating a polygon on the fly, i.e. an on-click polygon in action!

    The code for creating a polygon is very much similar to creating a polyline! The only difference is that you need to replace "Polyline" by "Polygon" in such examples. Let's head on to our code.

    The output of the above code can be viewed in the result section above. If you have any doubts or queries regarding the above code then please comment here or feel free to drop me a mail! Till then, happy mapping!


After having seen a number of examples of polyline using the Google Maps API, the obvious next step is to create polygons on the map! Today, we will start with a simple polygon example and later proceed with a few more ranging from simple to a little more complex! Let us now move on to the code. Copy the following code in a text file and save the file with .html extension. Click on this html file and it will open in your web browser. You will now see your map in action!

    In this example we will see a hard-coded polygon, i.e. with no user interaction! No user-clicks, no drags, nothing at all! The polygon will directly appear on the map! Following is the code for the same.

    The output of the above code is as seen in the result section above. If you have any doubts or queries regarding the above code, leave a comment here or feel free to drop me a mail!

Satellite to keep eye on Chambal, Palpur Kuno sanctuaries

In a bid to check the rising incidents of poaching and keep an eye on the flora and fauna of the two sanctuaries in Madhya Pradesh, the government has decided to use satellite to monitor the Chambal and Palpur Kuno region.

         The basic field technique, which is used currently, to maintain a log of the region’s vegetation, wildlife does not give the real time data. Therefore, the government has decided to use the Geographical Information System (GIS) Global Positioning System (GPS) for the purpose.

         Madhya Pradesh’s leading animal scientist Dr. RJ Rao, who has received training in such satellite monitoring of national reserves from California, said the program ‘ARC Q-9’ is proving to be of great use in protection of the wildlife. They have used the program to prepare a database of the whole Chambal and Kuno region, said Rao.

Source: DaynikBhaskar

Onclick geodesic polyline

We have seen what is geodesic polyline and its example in the previous post. We have also seen a simple polyline example before. It's now time for an onclick geodesic polyline example and I will discuss it here today. Let's head on to the example straight away...

    You can copy the above code in a text file and save it with .html extension. Now click on this html file, which will open it in your browser and you will see your map in action! The output of the code looks as seen in the result section above.
    There is one thing that needs explanation in this code. The use of geometry library in the script tag. What is this geometry library and why is it required will be an obvious question. This library is not loaded by default when you load the Maps Javascript API but must be explicitly specified through use of a libraries bootstrap parameter. The Google Maps JavaScript API V3 geometry library provides utility functions for the computation of geometric data on the surfa…

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 not …

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, assistant or executive engineers will visit construction sites every two days to take pictures of constructed roads and upload them on the RCD website. Photos take…

Orissa Cheif Minister launches "Odisha Sampad"

The Orissa Chief Minister Naveen Patnaik dedicated ‘Odisha Sampad’ a Web-based Block GIS Atlas developed by the Orissa Space Application Centre (ORSAC) to the people of the state on 4 January.
          The objective of ‘Odisha Sampad’ is to provide datasets of all the 314 blocks (village-wise) of the state relating to natural resources, environment, infrastructure, socio-economic and demography. The information content has been built on the basis of satellite image interpretation, survey at the block level and maps of other departments and agencies. The web atlas contains information on natural resources like land, utilization distribution of wastelands, forest lands, agriculture area, plantation, settlement, waterbodies etc.
          It also contains information on soil, slope, lithology, drainage, geomorphology, ground water potential, said an official. All the administrative bouridaries like state, block, GP, village, Assembly Constituencies, Parliament Constituenc…

Indian Archeologists discover prehistoric maps

An archaeological team, led by T M Keshava from Bangalore, discovered maps that date back to 1500-2000 BC. The place is located around Tungabhadra River near Hampi in Karnataka, India. Unlike modern maps that rely on technology, ancient men banked on their eyesight and memory.

          The map was depicted on the roof of caves of Chikramapura village. What was once thought to be a megalithic burial site with just paintings of animals and humans; is proof of the prehistoric man’s cartographic skill. Keshava’s finding is believed to be the first-ever aerial map of a region drawn by a prehistoric man. While paintings of animals such as cows, hunting scenes and human figurines are common across pre-historic settlements, only the Chikramapura village caves, also called Kadebagilu rock shelters, feature maps.

          “A previous study in 1984 at these caves by scholars like Dr R Sundara had concluded they were just megalithic burials, but we can now say that they a…

Cops using new device to track down crime

The police have adopted a novel method to track down criminals involved in crime in and around Patna with the introduction of Geographic Information System (GIS) by the state police headquarters.
         The system which is being manned round the clock by 5 SIs and 2 dozen constables, has so far yielded tangible results, Patna City SP Manu Maharaj said. He is himself monitoring the entire new system.
         The new system had helped the police in detecting and solving about 50 cases in Patna during the past 18 months. The GIS is so sensitive that police can locate criminals' hideouts. With the help of GIS, Patna police have been able to arrest about 11,020 criminals between July 2009 and November 2010. During raids at criminals' hideouts with the help of GIS, police seized about 397 illegal weapons, 6,592 live cartridges, 72 magazines, 81 live bombs and Rs 32.21 lakh cash, the City SP said adding that 14 abducted persons were also rescued by police with the …

Concluding GIS India news of 2010

Vietnam, India ink deal to develop GIS technologies:
          A delegation from the Vietnamese Ministry of Science and Technology has signed deal with India for the deployment of GIS technologies. The GIS deal aims to spot areas vulnerable to droughts in service of agriculture and forestry and extracting substances from starfish in service of the pharmaceutical industry. To  know more visit the source of the news.
Shoreline maps of Gujarat and Puducherry released:           Jairam Ramesh, Minister of State for Environment and Forests (I/C) launched the shoreline study maps of Gujarat and Puducherry. These maps are approved by the respective state governments. The coastline of India is undergoing changes due to various anthropogenic and natural interventions. Most of the shoreline chanes are on account of the structures which have been developed/ constructed along the foreshore of the country. Several of these developments are not compatible with the dynamic nature of the shoreline.