april project hydrology dem technical process
DESCRIPTION
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.TRANSCRIPT
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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
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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
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And separate river pattern with other pattern, Do raster calculation: con (file >=2, file)
7. Stream link
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8. Stream order
9. Stream feature
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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.
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Dissolve stream feature based on grid code
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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
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Result:
11. Creaste watershed
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Convert raster watershed to vector format use from raster to vector tool