ArcHydro: Python Script: Centroidal Flow Path

Question

I'm looking for assistance from the ESRI community to write a python script that will calculate the Centroidal Flow Path of  based on the Longest Flow Paths and Drainage Area Centroid. I need to project a line at right angles to the Longest Flow Path split the Longest Flow Paths, remove the segment upstream of the Drainage Area Centroid and report the remaining segments as the Centroidal Flow Paths for each Watershed. I've attached a image to better explain what I'm trying to accomplish. The reason for wanting to script this is that I would like to embed this into my current ArcGIS Model that I've developed using ModelBuilder.

Regards

CentroidalFlowPath.jpg

MarkBoucher · Answer

HEC-GeoHMS keeps crashing my ArcGIS as its currently only available in Beta for ArcGIS 10 at this stage.

Interesting. It does say GeoHMS for ArcGIS 10.0 is an "Early Access Preview (EAP)", but I've been using it for a while with little problem.

PeterWilson · Answer

Hi Mark

As soon as I've figured out how to compile a python script to accomplish Centroidal Flow Length, I'll post the code on the forum. HEC-GeoHMS keeps crashing my ArcGIS as its currently only available in Beta for ArcGIS 10 at this stage. I'm also running a later version of ArcHydro that not compatible with HEC-GeoHMS at this stage. I'll keep you posted.

Regards

MarkBoucher · Answer

There is a tool in HEC-GeoHMS that does this. The program is written by ESRI and I found you don't have to create a GeoHMS project to used the tool. You just have to set the layers in the Data Management setting.

Download it from the Corps of Engineer's HEC site (http://www.hec.usace.army.mil/software/hec-geohms/download.html) and install it. I believe HEC-GeoHMS 10 will, or will try, to install ArcHydro 10 also, so be aware of that in case you are working with an older version of ArcGIS.

For you ESRI folks who might be listening, it would be handy to have this tool in ArcHydro.