Wednesday, May 30, 2018

Maps: Getting Your Bearings Right

A flick of your finger - that is all it takes now to zoom through the most detailed maps. Every now and then, whenever I call a cab from Uber or Ola, locate an office or eatery, wander through Google Earth or just seek the easiest way to dodge traffic jams, I wonder at the many conveniences we now take for granted. 

Come to think of it: Mapmaking has indeed come a long, long way. 

In India it started in 1802 as a project initiated by the East India Company to ensure accuracy when it came to exploiting newly subjugated territories, and for waging military campaigns. A project that started out from Mysore, after the defeat of Tipu Sultan, went on to be called the Great Trignometrical Survey.

Using nothing more than ropes, link-chains and theodolites, an infantry officer, William Lambton and his team calculated heights and distances across the entire subcontinent. It was during this survey that the highest mountain peak on earth was identified deep in the Himalayan ranges, and named after Lambton's successor, George Everest. 

Further north, when the surveyors were blocked from entering Tibet they sent spies who, dressed as buddhist pilgrims, would keep track of the steps they walked each day, to map the rivers and mountains of the Tibet, for the first time. The story of Nain Singh and nephews is now stuff of legend.

The organisation once headed by Everest - the Survey of India - became zealous custodians of maps, all the way from the 1800s to the early 2000 until it woke up and realised, like Rip van Winkle, that the art and science of mapmaking had been revolutionsed by satellites and the internet. You no longer needed a written permit from the Surveyor General of India to map your streets, villages, towns and cities - it was now openly available from satellite images with the finer details crowd-sourced by users.

Willingly or otherwise everyone with a smartphone is now a mapmaker. With location coordinates being uploaded in real-time, along with inputs from millions of accelerometers, we all now have access to fairly accurate information to help us plan better.

What are the ways in which your location coordinates are being shared over the networks?

* LatLong: Traditional ways of marking a location with lattitude-longitude coordinates with a little help from all the GPS satellites hovering in the MEO ~20,000 km up there. Online tools now allow you to get both coordinates up to 14 decimals!

* DMS: A standard developed by World Geodetic System (WDS-84) goes in the Degrees-Minutes-Seconds (DMS) format and is said to have an accuracy of up to 1cm!

* Plus Codes: Perhaps the latest format, this was developed by Google as Open Location Codes. A plus code is 10 characters long, with a plus sign before the last two. It consists of two parts: (1) The first four characters are the area code, describing a region of roughly 100 x 100 km, and (2) The last six characters are the local code, describing the neighborhood and the building, an area of roughly 14 x 14 meters – about the size of one half of a - basketball court.

Add any of these codes to a spreadsheet and you can easily create maps that get your bearings right, down to the 14th decimal!


- Geolocation Coordinates --
- GPS Coordinates -
- Google OLC -
Plus Codes - 

- Data Visualizaition Tools -
- Google My Maps -
- KML files - Keyhole Markup Language -

- Importing Spreadsheets into Google Maps -


* Keay, John (2010): The Great Arc: The Dramatic Story of How India Was Mapped and Everest was Named

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