ストリーム内の流れ方向を調整する

Question

<\/HEAD>こんにちは、<\/P> <\/P> 「Adjust flow direction in streams」ツールの正しい使い方を理解しようとしています。私の理解では、これは循環領域を含むストリームシステム（ストリームの焼き込み）を適用する際に使用されるべきものです。私のワークフローは以下の通りです：<\/P> <\/P> 1. シンクを埋める<\/P> 2. DEMの再調整<\/P> 3. シンクを埋める<\/P> 4. 流れ方向<\/P> 5. 流量蓄積<\/P> 6. ストリーム定義<\/P> <\/P> その後、「Adjust flow direction in streams」ツールを実行し、「Stream flow direction grid」としてワークフローのステップ6の結果を使用しています。これは正しいアプローチでしょうか？<\/P> <\/P> ご助力いただきありがとうございます。また、この質問が既に尋ねられ回答されている場合はお詫び申し上げます。<\/P> <\/P> アレックス。<\/P><\/BODY><\/HTML>

ChristineDartiguenave · Answer

You will use if you have known Streams you want to use.

Create Drainage Line Structures will create a rasterized version of those streams.

This tool also create StrLnk which you can use as input Str raster in DEM Reconditioning (this way we use the same raster).

Christine

AlexanderVentura · Answer

Hi Christine,

Thanks a lot for your reply. OK, I was following this manual:

http://downloads.esri.com/support/datamodels/Hydro/Comprehensive_terrain_preprocessing_using_Arc_Hydro_tools_2008.zip

and as far as I had understood it the "Adjust flow direction in streams" tool is used when burning in streams into my DEM but the streams have "braids", but I guess I had gotten this wrong.

So essentially I need to "burn in" streams (ditches or drainage systems rather) to "force" the water to flow in these. I have a detailed network of drainage lines available in vector (polyline) format. So far I have been using "DEM reconditioning" for this but you mention "Create Drainage Line Structures". Is this a process that should be performed before running the "DEM reconditioning"  tool? Or is "Create Drainage Line Structures" used when a vector of drainage lines is not available and needs to be created?

Thanks again,

Alex.

ChristineDartiguenave · Answer

You do not need to run the tool "Adjust flow direction in streams" when the streams are generated using Stream Definition based on the flow accumulation raster. This tool is used when the Streams (Drainage Line) are created using Create Drainage Line Structures, i.e. you are trying to match the geometry and digitized direction of input vector streams, which may not match the direction provided by the underlying terrain. This tool ensures that once the water gets into the stream, it follows the direction of the digitized input streams. In flat area, the water may not go the right way otherwise.

Christine Dartiguenave

Esri Water Resources Team