Why can't Indians access maps for 43 per cent of their country?

How is it that you can buy a map of India in Paris with details as fine as the location of all tyre puncture shops in Delhi (updated every six months)? And you cannot get it in Delhi itself? An Indian satellite can map each square metre of the country, but information -- even at levels of hundreds of square kilometres -- evades people A digitised map of India can be downloaded from Russian or US-based websites, but the Indian government labels, as 'restricted', the same information How is it that map making private companies decide for clients where to locate their new factories (after mapping relevant resources such as water, lack of congestion) when a villager cannot even see, or access information to, the extent of soil moisture depletion before an impending drought? Asks NITIN SETHI

Last Updated: Sunday 07 June 2015

Why can't Indians access maps for 43 per cent of their country?

-- Hilltop to desktop

Technology advances have transformed the way maps are made

When the Survey of India (SoI) was set up 237 years ago, in Dehradun, map making was akin to pure art. It required steady hands and a keen eye, and demanded months, at times years, of painstaking labour. The first maps were made on parchment using brushes.

The actual mapping of the land was an arduous process -- it involved iron chains (as a standardised unit of measure), and large theodolites (survey instruments which measure vertical and horizontal angles) weighing as much as 500 kilogrammes. The theodolite needed 12 people to haul it to vantage positions on hilltops, for map makers to accurately create a grid of landmarks.The mapping of India began in 1800 and it took more than 50 years to cover 2,575 kilometres with inch-perfect accuracy. Thus was created the Great Indian Arc of the Meridian -- a grid of reference points useful for all maps.

But that was 'back then'
Today, high-end computer processing and off-the-shelf satellite imagery (of course, at a price) make it possible to process maps, quite literally, from desktops. Also, high resolution satellite imagery obviates the need for extensive physical labour and surveys. One can now access finely resolved maps of any part of the world; one can single out a mango tree in a field or a car in a porch. These satellite images are available in the public domain. Spy satellites with far higher resolution capabilities, elusive for commoners, outdo even such super close-ups. A highly powerful tool for map making now is the Geographic Information Systems (GIS) which literally brings maps to life (see box: Layers of an onion).

Modern maps are also far more accurate than hand-drawn ones. For instance, for a cartographer tracing a line a millimetre thick on a map made to the scale of 1:1,50,000 (so a millimetre on the map would be 15 metres on the ground), a minor deviation of a centrimetre on the state boundary means as much as 1.5 kilometres on the ground. Digital map making reduces this error to a few millimetres. Advances in printing technology ensure high quality maps are easily available.

The digital revolution has democratised the making of maps. Unfortunately, it has not democratised the use of maps. Not in India. Not till date.

Mapping milestones

1767 First Survey General of Bengal appointed
802 The great trigonometric arc survey starts
830 George Everest appointed Survey General
1840 Cape Comorin to Mussoorie survey completed
1849 Mt Everest measured
1901 Magnetic survey begins
1956 First series of metric maps begins
1970 Computerisation begins
1982 Satellite-based mapping initiated
1992 Global Positioning System introduced
2001 National Spatial Database Infrastructure mooted

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