Tech Primer

Digital Mapping

What is digital mapping used for?

A digital map is created by mapping the real three-dimensional world onto a set of two-dimensional discrete points. Digital mapping refers to a collection of data and its interaction with a map. Data is used to make maps, analyse it to create new data and statistical summaries. Data mapping can be done in different formats—projections, scales, and file compression scheme. There are four categories of geographic data—

Images: aerial photos, scanned maps, satellite imagery etc.

Lines, points and areas: roads, power lines, lakes tower location etc.

Elevation: arrays of terrain heights.

Spatial Database: census data, resources inventory data.Digital photographs are called Digital Orthophoto (DOP) or Digital Orthographic Quarter Quadds (DOQQ).

Are there any popular examples of this technology?

Google Earth displays satellite images and it lets you zoom in on any corner of the world. MSN Virtual Earth is a similar service that has additional features like saving and sharing searches. Amazon.com provides street level photographs of businesses through its A9 search engine. Aerial maps are not new as Microsoft has operated a Web site called Terra server for some years now. Terra server provides a free source for digital topographics known as Digital Raster Graphics (DRG). There is an another Web site called Terra Fly.

Can digital mapping be counted as a security threat?

Digital mapping is perceived as a threat by many countries. The claim is that terrorist organisations can easily have a closer look at the government buildings and target them. Details of India’s aircraft carrier, INS Vikrant on Google Earth or an aerial view of Australia’s nuclear reactor Lucas Heights in Sydney reinforce such fears.

That said, digital mapping can be used to display disaster-prone zones and terrain.

How does the technology work? How detailed is the mapping?

MSN virtual Earth has satellite image at 45-degree angle of buildings and neighbourhood; satellite image with street maps and over lays, ability to show local business or restaurants. Google Earth and MSN Virtual Earth add real-word satellite imagery to the mix of roadmaps and local search. Google Earth users can toggle between a map view and a zoomable streaming aerial view.

Which are the companies that are using Digital Mapping?

Some of the companies that are using Digital Mapping are CE Info Systems (India), Rolta India, SUMUL (India) and many more.

How is digital mapping beneficial in rural areas?

Digital mapping is beneficial in rural areas as it provides insights into various global issues like human settlement, agricultural lands, use of natural resource and its degradation, conflicts and diseases.

For more information visit www.digitalgrove.net
Links to sites mentioned in the story
www.a9.com
www.terraserer.com
www.terrafly.com
earth.google.com
virtualearth.msn.com

—Garima Grover

grover_garima@hotmail.com