Showing posts with label spatial data. Show all posts
Showing posts with label spatial data. Show all posts

Wednesday, October 12, 2011

Bhuvan Continues To Be A Mixed Bag As A Citizen Mapping Tool

After my last post on the use of Google Earth to identify illegal mining in Goa, I was curious to find out if I could replicate the same in Bhuvan, India's public mapping portal.

I was disappointed:

1)  There is no historical imagery available, or at least none that I could find.  So I could not pull out older imagery to verify claims made about the presence /absence of mining before a certain date.  This is not due to a lack of older imagery. The Indian Space Research Organization has had a remote sensing satellite program since the late 1980's and imagery  of at least 23 m resolution is available for  the last couple of decades and imagery of 5.8 meter resolution is available for the last 12 years or so (IRS - 1D). The 5.8 m resolution images are fine grained enough to identify large features like open pit mines.

2) I could not find the open pit mines using "search by name". In Google Earth I could zoom onto the area of the open pit mines by searching for the nearest settlement "Maina" which was mentioned in the article on the Goa mining scam by the newspaper Herald.   In Bhuvan, the search by name database works best for towns and cities. The village level data is still incomplete. Even when a small village is present in the database the imagery does not always zoom to that area, nor is the village annotated to allow easy navigation to it. These are the basics of interactive map navigation design and Bhuvan is falling short.

On a general note, its been close to three months since the government announced that 1 meter resolution data will now be available without need for security clearances. Yet Bhuvan still is not streaming imagery finer than 5.8 meter resolution.

On the data download front, elevation data of CartoDEM 1 arc second (Digital Elevation Model derived from Cartosat 1 imagery- 1 arc second corresponds to roughly 30 meters) and Resourcesat-1: AWiFS imagery (56m) of the Indian region can be downloaded from the NRSC Open EO Data Archive. You can choose the product and the area of interest from the Bhuvan interface. The DEM download is a welcome addition. You could previously download 1 km resolution DEM of India from the USGS and also 30 m relative DEM generated from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) from NASA.

However, regarding imagery the government's all too cautious approach is perplexing. If 5.8 meter resolution and 1 meter resolution data are available and now cleared for access to all users without further security checks, why not let users download that data too?

Monday, September 12, 2011

Data Problems In The Indian Geospatial Industry

Geospatial World has several articles (1, 2, 3 ) on the current state of the Indian Geospatial Industry. As I have been writing on this blog, there have been several initiatives taken by the Indian government to encourage growth of this industry. Of primary concern to users is the unavailability or slow availability of useful data.

Aditi Bahn Assistant Editor, Geospatial Media and Communications Pvt. Ltd. writes:

There is no single window where all the information can be obtained. For example, if a user requires information about topography and demography of a place, he has to approach Survey of India and Census of India respectively. The two have their own procedures in place and would provide data in their own time frame. She quotes industry specialists : 

“The overhanging issue is the availability of data under one umbrella. Information is scattered and varied and have to be collated very frequently. It has become extremely challenging,” explains Aiyer.

..and (Mr. Agarwalla) -  “Even before we talk about public-private partnership, we need to talk about public-public partnership. For most of my users, just the map or census data by itself is not good enough. So can Survey of India and Census of India partner together?”

That is not unusual. Having data in two or several different places need not by itself be a big problem. Even in countries  where spatial data is relatively freely available like the U.S, many state agencies and federal agencies have ownership of their data. Finding it though is easier by going to a central data listing like the one maintained by the U.S. National Spatial Data Infrastructure. Most government agencies who produce spatial data are registered with their NSDI and follow agreed upon data standards and data dissemination practices.

In fact it is inevitable that various central and state agencies responsible for the data will want to keep ownership of it. The Indian National Spatial Data Infrastructure (NSDI) was meant to deal with exactly this problem by issuing guidelines and standards for data creation, data storage formats and data access thereby enabling users to find and combine data from different agencies with ease. The important challenge is not whether different agencies can partner each other, but getting agencies to follow standard practices in a time bound manner. The NSDI portal would then list agency addresses to go to for your data needs.

I remember talking to a senior geologist with the Geological Survey of India in 2004. I was told that digitization of 1:1 million scale geological maps is almost done and work is going on the 1:250K and selected 1:50k series. Most of this data would be ready to go online by 2006. Five years since this self-proclaimed deadline, there is still no easy way to access geology digital data.

Why has the NSDI not been successful in getting organizations to cooperate in a timely manner?