And now, fly over Google Earth

A young IPS officer of my acquaintance was summoned to the RAW headquarters. New to Delhi, he required directions to this building, which is not officially labelled the "RAW HQ".

He was told to arrive in the locality and ask for the neighbouring building: we'll call it "Building A" in the interests of protecting national security. Getting into an auto, he asked the driver if he knew the location of "Building A". The auto-driver thought for an instant and then said: "Oh yes! That's right next to the RAW building!"

Nevertheless, RAW HQ remains officially off the map of Delhi. As do large chunks of the Cantonment, Rashtrapati Bhawan and Parliament. These places aren't marked on the superb digital Eicher maps of Delhi despite being landmarks.

High-res satellite pictures resolving down to about 3 feet focus with GPS location-tags are however, available for payment from a variety of sources.

The MCD, NDMC and other urban authorities will start using this data soon to map sewage systems and power lines, and crosscheck corporation tax payments and their database of addresses versus physical locations.

If you're a techno-savvy terrorist, you could also pass by various locales and mark them off on any GPS device and follow through with a low-res or medium-res satellite picture request "" this could narrow it down to block or individual building level.

But none of those are as easy to implement as simply looking up that selfsame set of navigational coordinates and then marking the location off on Google Earth.

Some nephew of Nishi Bua has already marked off her residence behind the Grand Hyatt "" this could turn into breach of privacy but I suppose Nishi Bua doesn't mind being put on the digital map.

Google Earth is similar to Microsoft's earlier concept of Virtual Earth. Both are free, both use a mix of satellite images of various resolutions to offer detailed locational information. You can search for landmarks, hotels, museums and routes between any two points.

You can put placemarks on your personal copy of Google Earth (GE) to denote specific locales. You can share those placemarks with the entire GE community to improve everybody's local coverage.

Of course, Delhi is fairly low on GE's list of priorities and it doesn't have really high-res (1metre pictures) of Delhi. But you can make a fairly accurate guess at to the number of trees in Rashtrapati Bhawan and you can mark off most residential areas block by block as well as note the arterial roads.

And yes, the Air force base and Palam airport are marked as is Brar Square in the Cantonment and the Defence Services Officers Institute at Dhaula Kuan.

If you are travelling across thousands of different locales in the Euro-13 and in North America, GE is an absolute killer app because it offers 1 metre resolution on a free service and far more details. That is, you can't quite see Barney's poop on the lawns of the White House but then again he may have buried it!

The fact that the GE community can share info through the placemarks naturally improves everyone's utility to the network and it allows Google to leverage the embedded knowledge of its user-community.

Uncontrolled place-marking can lead to jokes in somewhat dubious taste "" the London Police were distinctly unamused when a station house in London was place-marked "local cat-house". There can be mislabeling and mis-spelling ("Mirat" for Meerut) apart from plain misdirection.

For once, the Indian government has been sensible "" it has simply decided that you cannot stop technology and taken steps to live with the increasing availability of such services.

The GE service does require a fairly high-end PC configuration and a good Net connection. The chip needs to be at least a P4 2.4 MhZ equivalent and it must have 3-D capability. A Mac version isn't available yet. As to connections, to avoid great tedium you will need broadband and as of now, you must hope that high-res coverage will continue to improve across more and more locales.

Setting up the service is simple. Just go to Google Earth and download the client onto a machine that fits the configuration requirements. There's an easy set of controls, which can mouse-clicked for directions, zoom and pan factors. Simply using a rollover mouse and hot keys is also possible.

To set a placemark, search for a location using the zoom and pan controls to zero-in. Then click the pin icon in the display. This brings up a menu and drag the pushpin icon that appears to the location you want. Then enter text into the dialogue menu.

You can bookmark your placemarks and tour them. If you connect different cities on different continents you will be "flown" between locations. You can also save your placemarks and share them with others, either by email, or by uploading them to the Google Earth community forum.

Finding and saving placemarks is cool, but why stop there? Google Earth also lets you make and save search results related to a particular location and hotels, cathouses, museums, etc. One way is to simply drag the search result folder icon to the relevant folder in "My Places".

This is the service where the search engineers from Mountain View, Ca leverage their formidable local databases and this free service to generate revenues. Another fun feature lets you fly along a route that's created when you request driving directions. Simply enter your starting and ending point into the "directions" search boxes, and once the route is mapped, click the play icon.

You can control the speed of the tour and pause when you like. This technique will test the limits of most governments since there is a degree of jitteryness in official circles about the zoomed images. But the fact is the data has been available for years. Google Earth has just made it slightly more accessible.