Technology topography: Mapping India through drones

What has Ramanagara, the location of the fictional Ramgarh of Bollywood superhit Sholay, got to do with drones? During the past few weeks, the unmanned aerial vehicles have been hovering over the skies of the town, about 50 km from Bengaluru, flying at regular intervals to quietly capture images of the land below.

From buildings to farm land, roads and lakes – the drones are mapping the area as part of a joint initiative by the Karnataka government and the Centre to digitally map the country.

The project, starting with Karnataka, Maharashtra and Haryana, is an ambitious initiative to carry out a drone survey across India to create high resolution digital maps of the country. The Survey of India, the country’s oldest scientific agency, has been tasked with doing this.

Karnataka’s revenue department, in turn, is using the images captured by these drones to create digital maps and ownership records of every piece of property.

Last year, the revenue department and the Survey of India successfully completed a pilot project in Jayanagar, the city’s first planned suburb. Its accuracy level has now prompted the department to expand work in other districts.

For long, land survey in India was done manually, with surveyors measuring land parcels and generating records. With the advent of technology, Survey of India, along with state and city government agencies, started using satellite images to map properties and create near accurate images. However, the evolution of drone technology seems to have opened up new possibilities in land survey.

Taking a cue from the three states which approached it for the survey, the agency now sees it as an opportunity to create a repository of drone images across India, similar to the repository of satellite images by the Indian Space Research Organisation.

“We have carried out many surveys in the past, but not at this resolution. If the accuracy level of satellite images is 30-40 cm, drone images are as accurate as 5 cm. That is the kind of precision we are looking at,” Surveyor General of India Girish Kumar told ET.

A survey of this magnitude is the first of its kind in the world, experts say. While drones have been used to measure areas of a few hundred square kilometres, the project that the Survey of India and the three states have taken up is huge. The land survey agency has so far procured 30 drones and plans to increase the fleet to 300 soon.

Haryana has achieved much progress in the survey work, while Maharashtra has limited the survey to only villages in the first phase. The work in Karnataka is more complex as both urban and rural areas including Bengaluru will be surveyed in the first phase itself.

The exercise involves capturing images through drones, corroborating it with the ground survey data and then developing it into a high-resolution 3-D map.

Even as the three states have voluntarily adopted the drone survey project, the agency has planned to simultaneously create a landrepository based on drone images across the country.

“The need to have a digital map of India was felt as it would enable better decision making in the government. The map will have all types of records including land details, socio-economic data, road network etc.,” Professor Ashutosh Sharma, secretary in Ministry of Science and Technology said during an event at the Indian Institute of Science, Bengaluru, recently.

There is more to the drone survey project than mere mapping. Karnataka is working on developing geo-referenced land records based on drone images.

“Today, land records are beyond comprehension for people. But, using the drone survey data, we want to develop a digitised map - similar to Google Maps - for every piece of land. A person can actually visualise the property and the boundary,” said Munish Moudgil, Survey, Settlement and Land Records commissioner, Karnataka.

The new system allows the surveyor -- carrying a connected device continuously operating reference stations -- to walk precisely on the property boundary, which until now was challenging, especially on agricultural land. “Any changes made to the property thereon, will be continuously updated,” Moudgil said. Five districts in Karnataka have been chosen for drone mapping and to develop geo-referenced land documents in the first phase, and the work is expected to be complete by the end of next year.

In Jayanagar 4th block, where the pilot was carried out, officials said that they have compared the dimensions of drone sketches with the actual dimensions in the field and have found the images to be satisfactory. As a next step, at least 4,000 property owners are likely to get digitised geo-referenced draft property ownership cards by the end of December.

Since land ownership records in India are private documents and are presumptive in nature, the generation of digitised property ownership cards based on the drone survey could see a shift in the nature of land ownership from presumptive to conclusive titles.

“A project like this can dramatically alter the landscape of computerisation of land records. A land information system can be created in a short span of time and in a cost effective manner, eventually serving the public at large,” said ESRI India president Agendra Kumar.

ESRI is the country’s leading Geographic Information System (GIS) software and solutions provider. Other states are experimenting with survey and digitisation of land records based on satellite images of ISRO.

Rajasthan is re-surveying 12 districts through satellite imagery. “We have already procured satellite images. The next step is to autorectify these images and process and superimpose them on already digitised old cadastral maps,” said Mahendra Kumar Parakh, additional commissioner, Settlement. Cadastral maps show the extent, value and ownership of land.

Since the satellite-based survey in Rajasthan has so far been limited to villages, agricultural land owners are quite comfortable with the accuracy of satellite image. “Slight difference does not bother them,” he said.

In a country where courts are clogged with land disputes, the best takeaway of the drone survey could be to resolve land-related litigations. According to an estimate, about 2.5 million hectares of land in India are under dispute and 25% of the cases decided by the Supreme Court are of land conflicts.

“Accuracy level of the drone survey and the creation of digitised land records, will be a boon to resolve land disputes. Since courts have considered satellite images as valid proof in many litigations in the past, the drone survey images could now as well replace satellite images,” said M Jayachandran, project director, Karnataka State Remote Sensing Applications Centre.

Besides generating geo-referenced land ownership documents and resolving land conflict, the drone data is expected to be useful at various levels. “The data created through this project will be usable for many other applications, like land use planning, water resources etc. Additionally, this project can offer significant economic and governance benefits to states as there will be much higher transparency in land records,” Kumar of ESRI said.

Yet, a survey of this magnitude is not devoid of challenges. Weather is one such.

Survey of India officials say that they did not fly drones for months in Karnataka due to extremely unpredictable weather. “We could not fly drones during rains. At one point, a crash happened,” an official said. Despite limitations, subject experts hope that drones could be the next big thing for surveying properties.

“Every technology, be it satellite images, aerial survey or drone survey, comes with merits and limitations. The advantage of satellite imagery is that it can cover larger distance in a short period of time and weather is not a factor, unlike drones. But, accuracy and cost-effectiveness are the advantages of drones,” Jayachandran said.

The biggest challenge, experts say, is in processing and managing the data obtained from the survey.

“These drones will generate terabytes of data. The investment, therefore, should be on setting up a system, be it data processing, software, hardware to process data,” Jayachandran said.

Kumar, too, echoed the thought. “It is essential to meet processing requirements to complement the data collection activity. The requirement of trained manpower will also be an important factor for the execution of such projects.”