Remote Sensing: Overlay Analysis

An overlay operation is much more than a simple merging of linework; all the attributes of the features taking part in the overlay are carried through. In general, there are two methods for performing overlay analysis—feature overlay (overlaying points, lines, or polygons) and raster overlay. Some types of overlay analysis lend themselves to one or the other of these methods. Overlay analysis to find locations meeting certain criteria is often best done using raster overlay (although you can do it with feature data). Of course, this also depends on whether your data is already stored as features or raster. It may be worthwhile to convert the data from one format to the other to perform the analysis.
Weighted Overlay
Overlays several raster files using a common measurement scale and weights each according to its importance.
The weighted overlay table allows the calculation of a multiple criteria analysis between several raster files.
Raster- The raster of the criteria being weighted.
Influence- The influence of the raster compared to the other criteria as a percentage of 100.
Field- The field of the criteria raster to use for weighting.
Remap- The scaled weights for the criterion.
In addition to numerical values for the scaled weights in Remap, the following options are available:
Restricted- Assigns the restricted value (the minimum value of the evaluation scale set, minus one) to cells in the output, regardless of whether other input raster files have a different scale value set for that cell.
No data - Assigns No Data to cells in the output, regardless of whether other input raster files have a different scale value set for that cell.
THIS PRESENTATION IS TO HELP YOU PERFORM THE TASK STEP BY STEP.

1. OVERLAY ANALYSIS KAMLESH KUMAR

2. An overlay operation is much more than a simple merging of linework; all the attributes of the features taking part in the overlay are carried through. In general, there are two methods for performing overlay analysis—feature overlay (overlaying points, lines, or polygons) and raster overlay. Some types of overlay analysis lend themselves to one or the other of these methods. Overlay analysis to find locations meeting certain criteria is often best done using raster overlay (although you can do it with feature data). Of course, this also depends on whether your data is already stored as features or raster. It may be worthwhile to convert the data from one format to the other to perform the analysis. Weighted Overlay Overlays several raster files using a common measurement scale and weights each according to its importance. The weighted overlay table allows the calculation of a multiple criteria analysis between several raster files. Raster- The raster of the criteria being weighted. Influence- The influence of the raster compared to the other criteria as a percentage of 100. Field- The field of the criteria raster to use for weighting. Remap- The scaled weights for the criterion. In addition to numerical values for the scaled weights in Remap, the following options are available: Restricted- Assigns the restricted value (the minimum value of the evaluation scale set, minus one) to cells in the output, regardless of whether other input raster files have a different scale value set for that cell. No data - Assigns No Data to cells in the output, regardless of whether other input raster files have a different scale value set for that cell.

3. Add both the classified and unclassified image to the window but the task should be performed on the unclassified image as shown in the image.

4. Layer – 1 Rainfall

5. Rainfall Point file TO IDW(Output cell size - 50)

6. Reclassification OF IDW

7. Reclassified IDW

8. Layer 2: Geology

9. POLYGON TO RASTER

10. Reclassified Layer

11. Layer – 3 Landuse

12. Polygon to Raster

13. Reclassified Layer

14. Layer -3 Faults

15. Calculate Distance (Euclidian Distance)

16. Reclassified Layer

17. Layer 5: Drainage

18. Calculate Density (Line Density with Radius-500)

19. Reclassified Layer

20. Layer 6: Relief

21. Create TIN

22. TIN to Raster layer (DEM)

23. Neighbourhood → Focal Statistics

24. Reclassified Layer

25. Layer 7: Slope

26. Raster layer (DEM )

27. Slope

28. Reclassified Layer

29. Layer 8: Mobile Towers

30. Surface Viewshed

31. Reclassified Layer

32. Layer 9: Road

33. Distance(Euclidian Distance)

34. Reclassified Layer

35. Spatial Analysis Tool → Map Algebra → Raster Calculator formula – (Priority 1 * Layer 1)+(Priority 2 * Layer 2)+(Priority n * Layer n) INTEGRATION OF ALL LAYERS

36. Raster Calculator

37. Reclassified FINAL Layer

38. Signing off..