---
share_link: https://notesx.azraftaohid.me/ke09k730
share_updated: 2026-08-26T09:32:20+06:00
---
1. [River Morphology](#River%20Morphology)
	1. [NDWI](#NDWI)
		1. [Procedure (2013)](#Procedure%20(2013))
		2. [Procedure (2026)](#Procedure%20(2026))
	2. [Find out Total Erosion](#Find%20out%20Total%20Erosion)
		1. [Find out Unchanged Area or Common Area](#Find%20out%20Unchanged%20Area%20or%20Common%20Area)
		2. [Calculate Erosion/Aggredation](#Calculate%20Erosion/Aggredation)
		3. [Overly Erosion](#Overly%20Erosion)
		4. [Overly Accretion](#Overly%20Accretion)
		5. [Calculate Erosion/Accretion](#Calculate%20Erosion/Accretion)
	3. [Prepare Output on Excel](#Prepare%20Output%20on%20Excel)
	4. [Bar Computation (Manual Method)](#Bar%20Computation%20(Manual%20Method))
		1. [Compute Change in Area](#Compute%20Change%20in%20Area)
		2. [Summerize on Excel](#Summerize%20on%20Excel)
		3. [For Exam](#For%20Exam)

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## River Morphology

### NDWI

$$
\frac{B3-B5}{B3+B5}
$$

#### Procedure (2013)

- Add `.TIF` files from 2013
- Open ArcToolbox:
	- Spatial Analyst Tools > Math Algebra > Raster Calculator
	- Apply above mentioned formula:
		```
		Float("LC08_L2SP_138043_20131215_20200912_02_T1_SR_B3.TIF"-"LC08_L2SP_138043_20131215_20200912_02_T1_SR_B5.TIF")/Float("LC08_L2SP_138043_20131215_20200912_02_T1_SR_B3.TIF"+"LC08_L2SP_138043_20131215_20200912_02_T1_SR_B5.TIF")
		```
	- OK
- Add the `.shp` file
- Make the added shape file hollow and add boundary
- Select areas of interest from the shape file (hold `SHIFT`), then export as shape file and add the selected features
- Spatial Analyst Tools > Extraction > Extract by Mask:
	- Input Raster = exported composite file (`lc08...`)
	- Feature mask data = StudyArea
	- Done
- Hide/remove non-required layers
- Open Properties > Symbology > Stretched of `Extract_lc082`:
	- Stretch type = Custom
	- OK
- Spatial Analyst Tools > Reclass > Reclassify:
	- Input raster = `Extract_lc082`
	- Classify > use 2 (rest default)
	- OK
- Change symbology of `Reclass_Extr1` with white and blue colors
- Conversion Tools > From Raster > Raster to Polygon:
	- Input raster = Reclass_Extr1
	- Choose an appropriate output name: `...`
- Select river by selecting on a point of the river
- Exported polygon > Data > Export; use appropriate name, e.g., `ShpRiver2013`

#### Procedure (2026)

- Same as 2013

### Find out Total Erosion

- Open Attribute Table of ShpRiver2013
- Add field: `Area_2013`; type = double
- Calculate geometry: area, hec
- Perform the above three steps for `ShpRiver2026`

#### Find out Unchanged Area or Common Area

- Geoprocessing > Intersect:
	- Input Features = ShpRiver2013, ShpRiver2026
	- Rename with `UnchangedArea`
- Calculate area of generated layer: Unchanged_Area

#### Calculate Erosion/Aggredation

- Erosion = NextYearArea - UnchangedArea
- Accretion = PrevYearArea - UnchangedArea

#### Overly Erosion

- Analysis Tools > Overlay > Erase:
	- Input = ShpRiver2026
	- Erase = UnchangedArea
	- Name = Erosion

#### Overly Accretion

- Analysis Tools > Overlay > Erase:
	- Input = ShpRiver2013
	- Erase = UnchangedArea
	- Name = Accretion

#### Calculate Erosion/Accretion

- Calculate geometry: Erosion_Area; Accretion_Area

### Prepare Output on Excel

...

---

### Bar Computation (Manual Method)

- Create new shape file `Bar2013` and `Bar2026` using Arc Catalog. Use coor of ShpRiver2013.
- Start editing > create features for Bar2026
- Draw by following ShpRiver2026
- Do the same with Bar2013
- Open attribute tables and add `B2026_Area`, `B2013_Area`

#### Compute Change in Area

- Intersect to obtain unchanged
- Erase with unchanged

#### Summarize on Excel

---

#### For Exam

- On certain year, whether erosion occurred more or accretion
- Summarize on Excel

...

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![[Pasted image 20260825090756.png]]

![[Pasted image 20260825090804.png]]