3D Analyst - Watershed from SRTM

63 %
38 %
Information about 3D Analyst - Watershed from SRTM

Published on May 23, 2007

Author: httsan

Source: slideshare.net

Description

Creating Watershed From SRTM DEMs
by Muhammad Arief Arianto

Creating Watershed From SRTM DEMs Advance Geographics Information System Muhammad Arief Arianto G051060071 MIT-NRM Bogor Agricultural University

Creating Watershed

From SRTM DEMs

Advance Geographics Information System

Muhammad Arief Arianto

G051060071

MIT-NRM

Bogor Agricultural University

Watershed is the upslope area contributing flow to a given location. Such an area may also referred to as a basin, catchments, subwatershed, or contributing area. Watersheds can be delineated from a DEM by computing the flow direction and using it in the Watershed function.

Watershed is the upslope area contributing flow to a given location. Such an area may also referred to as a basin, catchments, subwatershed, or contributing area.

Watersheds can be delineated from a DEM by computing the flow direction and using it in the Watershed function.

STUDY AREA

GENERAL PROCEDUR This process will conducted by using arcgis92 software. There are seven main steps to create a watershed, they are : Create DEM from SRTM data; Remove Error Sink in the DEM; Generate Flow Direction; Generate Flow Accumulation; Generating Channel; Generating Stream Link; and Generating Watershed

GENERAL PROCEDUR

This process will conducted by using arcgis92 software. There are seven main steps to create a watershed, they are :

Create DEM from SRTM data;

Remove Error Sink in the DEM;

Generate Flow Direction;

Generate Flow Accumulation;

Generating Channel;

Generating Stream Link; and

Generating Watershed

Creating Dem using 3DEM Open 3Dem SRTM software Click file and chose load terrain model and a new windows will appears Chose SRTM Data (hgt) on file type and than press OK button

Open 3Dem SRTM software

Click file and chose load terrain model and a new windows will appears

Chose SRTM Data (hgt) on file type and than press OK button

Load the filled HGT tiles. Chose the smaller area from hgt files by clicking on operation menu and click select smaller area or by pressing F8 button on keyboard.

Load the filled HGT tiles.

Chose the smaller area from hgt files by clicking on operation menu and click select smaller area or by pressing F8 button on keyboard.

Reproject the DEM to UTM by clicking on operation menu and choose change projection Write the data out as GeoTiff DEM by clicking file menu. The data is now ready to be added to ArcMap, but still there are negative values even though SRTMFill was used, and that Should be cleaned. It is necessary to replace these negative values. To remove negative values use Spatial Analyst raster calculator. Use the conditional statement : “ con([Palu.tif] < 0, 0, [Palu.tif]) ” This is a Visual Basic- like command and is interpreted as if the raster value of Pamong.tif is less than zero then replace the raster value with zero otherwise replace it with the original value.

Reproject the DEM to UTM by clicking on operation menu and choose change projection

Write the data out as GeoTiff DEM by clicking file menu.

The data is now ready to be added to ArcMap, but still there are negative values even though SRTMFill was used, and that Should be cleaned. It is necessary to replace these negative values. To remove negative values use Spatial Analyst raster calculator.

Remove Error Sink in the DEM Before removing error sink, we should convert DEM type from floating point to integer Because elevation more dealing with integer number. Procedural steps for converting are Activate the spatial analyst extent ion, click on spatial analyst menu bar and chose raster calculator. Apply formula below “Int ([palu.tif])” and press evaluate button. The result will be automatically named by arcmap as Calculation, and store the information on folder Calc

Before removing error sink, we should convert DEM type from floating point to integer Because elevation more dealing with integer number. Procedural steps for converting are

Activate the spatial analyst extent ion, click on spatial analyst menu bar and chose raster calculator. Apply formula below “Int ([palu.tif])” and press evaluate button. The result will be automatically named by arcmap as Calculation, and store the information on folder Calc

The output is a temporary GRID. To make it permanent right click the file named calculation and select Data and choose make permanent If a cell is surrounded by higher elevation cells, the water is trapped in that cell and cannot flow. The Fill Sinks function modifies the elevation value to eliminate these problems. To remove an error sink, use the Fill tool in Hydrological Modeling Tools. Input surface raster by choosing calculation file name, choose the file name want to used, and let the Z limit because this is optional

The output is a temporary GRID. To make it permanent right click the file named calculation and select Data and choose make permanent

If a cell is surrounded by higher elevation cells, the water is trapped in that cell and cannot flow. The Fill Sinks function modifies the elevation value to eliminate these problems. To remove an error sink, use the Fill tool in Hydrological Modeling Tools. Input surface raster by choosing calculation file name, choose the file name want to used, and let the Z limit because this is optional

Result Before Applying After Applying

Generate Flow Direction The Flow Direction function takes a grid as input, and computes the corresponding flow direction grid. The values in the cells of the flow direction grid indicate the direction of the steepest descent from that cell. To showing the direction of flow, Click Spatial analyst tools, choose hydrology and choose flow direction by clicking the tool. To generate a flow directions use the previous result (result from removing sink error). Let the force all edge cells box and output drop raster as a default

The Flow Direction function takes a grid as input, and computes the corresponding flow direction grid. The values in the cells of the flow direction grid indicate the direction of the steepest descent from that cell. To showing the direction of flow, Click Spatial analyst tools, choose hydrology and choose flow direction by clicking the tool. To generate a flow directions use the previous result (result from removing sink error). Let the force all edge cells box and output drop raster as a default

Generate Flow Accumulation The Flow Accumulation function takes as input a flow direction grid. It computes the associated flow accumulation grid that contains the accumulated number of cells upstream of a cell, for each cell in the input grid. To create a flow accumulation, select the output flow direction file, and goto hydrologi toolbox which in on the spatial analyst tools, choose flow accumulation by clicking it, input the file name want to used, and let others as default

The Flow Accumulation function takes as input a flow direction grid. It computes the associated flow accumulation grid that contains the accumulated number of cells upstream of a cell, for each cell in the input grid. To create a flow accumulation, select the output flow direction file, and goto hydrologi toolbox which in on the spatial analyst tools, choose flow accumulation by clicking it, input the file name want to used, and let others as default

Generating Channel Based on the flow accumulation, we can map stream channels where the water flows. This channel is based on the number of cells which flow into a specific cell. If we want large channels we use a larger number. For this Assignment will mappings all cells that has at least 400 cells that flow into it. Because the cell size is 90 m, these means we are mapping all cells that have a drainage area of at least 90 x 90 x 500 = 3.24 km2. This operation will done by choosing raster calculator and applying formula : ([FlowAccumulation]) >= 400.

Based on the flow accumulation, we can map stream channels where the water flows. This channel is based on the number of cells which flow into a specific cell. If we want large channels we use a larger number. For this Assignment will mappings all cells that has at least 400 cells that flow into it. Because the cell size is 90 m, these means we are mapping all cells that have a drainage area of at least 90 x 90 x 500 = 3.24 km2. This operation will done by choosing raster calculator and applying formula : ([FlowAccumulation]) >= 400.

Generating Stream Link After mapped stream channels we have to assign each individual stream segments a unique number. This is done with the tool Stream Link tool

After mapped stream channels we have to assign each individual stream segments a unique number. This is done with the tool Stream Link tool

Generating Watershed After conducting those operation, now ready to do surface hydrology analysis to generate watersheds. Use the tool watershed from hydrology toolbox. Input flowdirection file on the first input box, input streamlink file on second input box and let others as default

After conducting those operation, now ready to do surface hydrology analysis to generate watersheds. Use the tool watershed from hydrology toolbox. Input flowdirection file on the first input box, input streamlink file on second input box and let others as default

The last step After applying watershed operation are converting the result to vector format and doing some cliping, because some part of watershed crossing the coastline

The last step After applying watershed operation are converting the result to vector format and doing some cliping, because some part of watershed crossing the coastline

THIS IS END OF SLIDE…

THIS IS END OF SLIDE…

Add a comment

Related presentations

Related pages

3D Analyst - Watershed from SRTM, SlideSearchEngine.com

Creating Watershed From SRTM DEMs by Muhammby httsan ... Creating Watershed From SRTM DEMs Advance Geographics Information System Muhammad Arief Arianto ...
Read more

3D Analyst Watershed Lombok, SlideSearchEngine.com

By using 3D analyst will determined watershed as ... Viewing 3D using 3Dscene 3D using ArcView 3.3 3D of watershed 3D using original data SRTM . Add a ...
Read more

Comparison of watershed boundaries derived from SRTM and ...

Comparison of watershed boundaries derived from SRTM and ASTER ... accuracy of watershed boundaries ... Using Spatial Analyst, the watershed boundary ...
Read more

Using ArcGIS Online Elevation and Hydrology Analysis ...

ArcUser Winter 2015. ArcUser Main; ... an elevation profile and a viewshed and perform a watershed ... elevation data obtained from NASA's SRTM.
Read more

Hydrologic analysis of digital elevation models using ...

... 3D Analyst and Spatial Analyst ... watershed management and urban planning. ... (2003) describes the Shuttle Radar Topography Mission (SRTM) ...
Read more

Hartanto Sanjaya - HubSlide

Deriving Watersheds Area from SRTM in Central Celebesby Abd... 6 months ago. Business. 3D Analyst - Watershed Lorelindu. ... 3D Analyst - Watershed and ...
Read more

analysis of a digital elevation model in ArcMAP - YouTube

... of first and second order derivatives in ArcMAP using SRTM 3 ... analysis of a digital elevation model in ... watershed grids ...
Read more

DEM-Based Terrain Modeling - Esri

Make sure ArcView 3D Analyst is loaded. In the Create New TIN dialog box, set Height Source to Contour, Input As to Mass Points, ...
Read more