DEPARTMENT OF SCIENCE & TECHNOLOGY

GOVT. OF INDIA

Dr. BHOOP SINGH

DIRECTOR

TOPOGRAPHIC MAPPING ON 1:10,000 SCALE

USING HIGH RESOLUTION STEREO SATELLITE IMAGES

Task Force on 1:10K

DST constituted a Task Force under the Chairmanship of

the Secretary, Ministry of Earth Sciences, in June, 2009

with the following terms of reference:

• To carry out bench mark studies for preparation of maps

of 1:10K scale using different technologies.

• To prepare standard guidelines/ methodology

Pilot Project with APSRAC

Objectives

• Preparation of Topographic maps using high resolution

stereo satellite images on 1: 10,000 scale with 2 m

Contour interval through photo grammetric techniques.

• 2D Features extraction from ortho-rectified satellite images.

• Standardization of the approach & methodology

• The digital topographic database in UTM Projection on WGS 84 Datum

SELECTED DISTRICTS IN ANDHRA PRADESH

Various Topographic Layers

•• Revenue Village BoundaryRevenue Village Boundary

•• Taluk / Mandal BoundaryTaluk / Mandal Boundary

•• District BoundaryDistrict Boundary

•• State BoundaryState Boundary

•• SettlementsSettlements

•• Roads Roads –– All weather Roads All weather Roads

•• Culverts and BridgesCulverts and Bridges

•• Rail NetworkRail Network

•• Electric linesElectric lines

•• Telephone linesTelephone lines

•• CanalCanal

•• Drainage LinesDrainage Lines

•• Water BodiesWater Bodies

•• WellsWells

•• SpringSpring

•• ForestForest

•• ContourContour

•• Bench MarkBench Mark

•• ElevationElevation

•• SymbolsSymbols

CURRENT TECHNIQUES FOR PREPARATION OF LARGE SCALE TOPOGRAPHIC MAPPING

• Field surveying methods using chains and theodolites

• Total Station Survey

• Aerial photography

Field surveying methods using chains and Theodolites:• Tedious and Time consuming• Huge manpower requirement• Generally used for smaller areas• Difficulty in inaccessible areas

Total Station Survey :• Not cost effective• Tedious and Time consuming• Huge manpower requirement• Difficulty in inaccessible areas

Aerial photography :• Security clearances for flying – A major hurdle• Not cost effective & Time consuming• Difficulty of time series of Updation due to cost and time involved in aerial data collection.

Limitations in the conventional technologies

• With the advent of New Stereo Capable Satellites, it is proposed to explore the usage of High spatial resolution Stereo Satellite Data for large scale mapping

• With stereo satellite data availability, it is possible to prepare accurate topo maps larger than 1:10,000 scale.

• Geoeye-1/Worldview-1/Cartosat series of satellites with stereo mapping capabilities are a huge data source for large scale mapping

• Many countries have initiated plans to use these stereo satellite data for large scale mapping

ALTERNATIVE TECHNOLOGIES - Satellite Technology

Advantages of Stereo Satellite Technology…...

• Cost Effective

• GSD < 50 cm available

• Limited security clearances required

• Fewer Ground Control Points

• High Agility of Sensors which will enable cloud free data

• Complete Digital workflows

• Data Repetitivity

Various sources of Stereo Satellite Images and their spatial

resolutions

•Geo Eye - 0.50m Resolution

•World View-1 - 0.50m Resolution

•Cartosat - 2.5 m Resolution

•IKONOS - 1 m Resolution

•Quick bird - 0.61m Resolution

Sources of Stereo Satellite data

Pros and cons within these Stereo Satellites …..

• Geo Eye/World view will require more GCPs than Cartosat due to steerable sensor platforms

• Cartosat captures real time stereo (6 Sec delay) and the sensor platform is highly stable as both the sensors are fixed at an angle.

• Cartosat is much more Cost Effective than the other

• Spatial resolution of Geo Eye & Worldview-1 is much more superior than Cartosat.

• 10 meter contour is possible using cartosat data whereas the other data sources allows us to generate 2 meter contours

• 100 % Cloud free data is difficult to obtain from any of these sensors

World View-1 pilot study in India…

A case study by Digital Globe carried out a small part of Karimnagar district, A P

Used World view-1 Stereo Data (50 cm - GSD)

Created 2 meter contour and 0.5 cm Ortho-rectified Images.

Results published in Digital globe Road shows in India ( June – July 2009)

World View Pilot study - accuracies

13

Andhra Pradesh State Remote Sensing Applications Centre

Cartosat bench marks

A paper published by ADRIN, Secundrabad :

14

Recommendations of the T F

Feasibility

• Task Force recommends that Cartosat-1 stereo satellite data will be sufficient to generate thematic maps with limited topographic information on 1:10 K scale, in view of achievable planimetricaccuracy is of the order of 3-5 m and contours of 10 m interval can be derived.

• The content of the map should include contours, built up area, hydrography, communications, land cover, administrative boundaries, annotation, utilities and infrastructure details which are identifiable through Cartosat data with limited field observations and existing topographical mapping data.

• Indian Dataset to be utilized for project as it ensures complete coverage across the country for recent years. Cartosat -I and LISS IV orthorectified fused image will be sufficient enough to generate thematic maps with limited topographic information.

Recommendations continued

• The pilot studies established the standards and procedures for generation of thematic layers and also overlaying of cadastre information

• It is recommended that dual frequency GPS base station and rovers should to be used for collection of horizontal and vertical Ground Control Points (GCP) in the field.

Recommendations continued

• Where maps on scale 1:25,000 are not available, DEMs with 10 m GSD can be easily generated from the stereo images on digital photogrammetric work stations provided the height control points (BMs) are established, post-pointed and geo-referenced.

• It is recommended that all the thematic layers be generated upto level III of NRDMS data models provided in Annexure V and NRSC created topographic data models provided in annexure VI.

• A QC system based on NSDI/OGC/ISO standards and sampling methods will be used in the process of creating Topographic database. The approved confidence level in these cases for QC shall be 95%.

Implementation

The project of thematic mapping on scale 1:10,000 with limited topographic content can be implemented by NRSC and SOI.

Recommendation continued

Implementation

The project of thematic mapping on scale 1:10,000 with limited topographic content can be implemented by NRSC and SOI. The remote sensing centres in various States and other agencies including private organisation can be enlisted for carrying out this task in a reasonable period of 3 years.

Role of NRSC

NRSC will be the agency to provide stereo satellite imagery fromCartosat. NRSC can be entrusted with the task of extracting thematic data from the ortho images. The final product will be stored in NRSC and SOI. The metadata will be available through NSDI.

Recommendation continued

Role of SOI

SOI will provide the requisite ground control and carry out stereo photogrametry to generate ortho images and integration of thematic data and topographic data ,and SOI will also be a repository of data.

State/Regional Remote Centres

The State and Regional Remote Centres will also be enlisted for extracting thematic layers from the satellite imagery.

Maintenance of Data base

This data needs to be maintained at frequent intervals and all agencies will share the responsibility for maintenance of data base being created.

Recommendation continued

Financial Implications

The total area of the country is 3.2 million Sq.KM(approximate) out of which 2 million Sq.KM will need this data. However, in initial stages 100 districts identified as agriculturally distressed districts in various parts of the country can be attempted.

The total cost could be around Rs. 1700 crores @ Rs. 2 lakhs per sheet (3’ x 3’) covering an area of 25 Sq Km

THANKS