Thursday, March 5, 2009

Indian Space Org Not In Competition With Google

It's official. The Indian Space Research Organization's imaging service Bhuvan is not in competition with Google Earth. And the launch of this service is being delayed from March to who knows when. has an article by K. Raghu on Bhuvan with quotes from ISRO officials about what the service will offer users. In my earlier post on Bhuvan I had asked 4 questions about the service. We now have answers for some of them

My questions were:

1) Will the images from Bhuvan be superior to that provided by Google? - The answer to that hasn't changed. No they will not be superior at least for urban areas. Google and Bhuvan both have the capability of covering rural areas with high resolution imagery. Google currently does not cover rural areas in India with high resolution images, but that could change if they perceive a threat from Bhuvan.

2) Will ISRO make other data available? - Yes they will, but the details of the layers which you can overlay on the images are not known. In fact getting these layers available and in a format required by Bhuvan seems to be one of the reasons behind the launch delay.

3) Will Bhuvan be like Google Maps or like Google Earth? - It will be like Google Maps. I wrote about the difference between these two products. In short, Google Maps is a true web mapping service. The interface as well as the data is sent to the user from a remote server. Google Earth is not a true web mapping service. You have to download the software and run it from your local computer. Only the data is being sent to you from a remote server. This enables the highly sophisticated interface to function efficiently.

Bhuvan will not be a download like Google Earth. It will be a standard web enabled GIS just like hundreds of other web mapping applications. The novelty will be that it will use image data exclusively from Indian satellites. Maybe that's what the hype was about. In any case as far as image quality goes, the hype although a little misdirected is well deserved. The Indian remote sensing program has been a credit to the nation and I am glad that Bhuvan will expose this imagery to users beyond a small group of professionals.

After this clarification from ISRO about what the product is, it's time our media stops calling it a Google Earth Killer or a product that is going to compete with Google Earth or a product which is a variant of Google Earth. There is no need for Bhuvan to compete with Google Earth. It can be a very useful service on its own terms in the Indian context.

4) Will ISRO allow open access to the Bhuvan API? - ISRO has not clarified it's position on this yet. But very unlikely.

I play a role in this article too. A couple of days ago I answered some questions posed by the reporter K. Raghu on Bhuvan. I have been quoted:

Others such as Suvret Kher, an independent geographical information system expert, advocate opening of APIs would help people to embed Bhuvan in their own customized applications and overlay their own data, making for a more effective use of the product. “That is one way to popularize the use of the imagery,” he said.

Suvrat- please!!

The article perpetuated another misconception about images and how they represent the earth.

These satellites shoot images as small as a car on the street, to build a three-dimensional map of the world.

Wrong. You can't build a three-dimensional map of the world using only high quality satellite images. The satellite image has no information of elevation associated with it. You can interpret that an area has relief by the tonal variations but no actual Z dimension is encoded in the image data. For that you need a relief representation of the world known as a Digital Elevation Model or DEM. It's this model of the relief that gives you information about the elevation or the third dimension. You can then overlay or drape an image or any other data on this DEM - which can be graphically turned into a shaded wrinkled layer in the map viewer- and get a feel for the topography. Google Earth offers this 3D viewing with an additional tilt option.

Again, unless ISRO comes out with a list of layers on offer we won't know if terrain viewing in 3D is going to be part of the bouquet of services. As I mentioned in my earlier preview, the more functionality you add to a web mapping service the slower and more unwieldy it is likely to become. That ought to be a big limitation in making Bhuvan too complex, considering the poor bandwidth available to most Indian users.

This post series will follow developments of Bhuvan and the spatial data landscape of India as and when they happen. So, keep coming back.

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