Extraction of surface water bodies using QGIS
- 1. Water body extraction from satellite data
- 2. Source of Satellite Data Medium resolution Satellite imagery (landsat) can be downloaded with EarthExlporer (free registration)
- 3. USGS’s Landsat mission is the source for open satellite data with 30 meter spatial resolution 16 days temporal resolution 185 km swath 185 km X 175 km tile size Source of satellite data
- 4. Bands Wavelength (micrometers) Resolution (meters) B1 - Ultra Blue 0.435 - 0.451 30 B2 - Blue 0.452 - 0.512 30 B3 - Green 0.533 - 0.590 30 B4 - Red 0.636 - 0.673 30 B5 - NIR 0.851 - 0.879 30 B6 – SWIR 1 1.566 - 1.651 30 B7 - SWIR 2 2.107 - 2.294 30 B8 - Pan 0.503 - 0.676 15 B9 - Cirrus 1.363 - 1.384 30 B10 - TIRS 1 10.60 - 11.19 100 * (30) B11 - TIRS 2 11.50 - 12.51 100 * (30) Band Specifications of Landsat - 8
- 5. Working with satellite data A user friendly Open Source Geographic Information System (GIS) licensed under the GNU General Public License. An official project of the Open Source Geospatial Foundation (OSGeo). It runs on Linux, Unix, Mac OSX, Windows and Android operating Systems. That supports numerous vector, raster, and database formats and functionalities.
- 6. Multiple bands Raster layer stack Single band(s)
- 7. with RED GREEN BLUE True color composite
- 8. with INFRARED RED GREEN False color composite
- 9. Band suitablity for water body detection Water body as seen in Green Water body as seen in NIR ( Green – NIR ) ( Green + NIR )NDWI =
- 11. NDWI Result
- 12. NDWI Classified
- 13. NDWI Binary
- 14. Raster to Vector convertion
- 15. Extracted WATER BODIES Vector
- 16. *Note: Areas in sq.m. Possible to convert Area of each WATER BODY of Vector
- 17. Accuracy Improvements Normalization and Edge Detection algorithms can be adopted In order to Restructuring data Reduce data redundancy Improve data integrity Improve accuracy