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processing DEM 30 m for hydrological aspect. this document is step by step process for hydrologycal modeling. using envi as software processing so people can easy to star hydrology analysis.
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APRIL Project.
Hydrology - Technical process
By: Ida Bagus Ketut Wedastra - conservation planer -TNC
1. Download SRTM with 30m resolution from earthexplorer2. Crop DEM using polygon area (ROI)
3. Continue with Fill process….
4. Flow direction
5. Flow Accumulation
6. Stream networkYou will see raster data with river pattern on it. We will use Raster Calculator toolbar to separate river patern and non river. (raster calculation = log 10 (file).Result
And separate river pattern with other pattern, Do raster calculation: con (file >=2, file)
7. Stream link
8. Stream order
9. Stream feature
10. Create snap pour point (Outlet point)Show stream feature with legend color (using gridcode value)
Using Query for selective main streams based on grid code valueSelect value > 4.
Dissolve stream feature based on grid code
Select stream feature which are overlap with coastal line or border area of interest using select by location, than save it
Convert stream feature to point using Data Management Tools/feature vertices to pointUse point type = EndMake sure the point snaps with the stream
Result:
11. Creaste watershed
Convert raster watershed to vector format use from raster to vector tool