Fetch calculation for coastal areas

TamsenByfield — Wed, 02 Jun 2010 03:41:47 GMT

Hello.

I would like to calculate fetch estimates for several sites along a coast. The sites are represented by a point shapefile and relevant coastlines by a line shapefile. There are no available small-scale oceanographic data available for this area and I am relatively new to ArcGIS so have no scripting abilities yet. Does anybody have any suggestions for how to calculate fetch with such limited input?

Thank you.

Re: Fetch calculation for coastal areas

BradPosthumus — Wed, 02 Jun 2010 20:27:08 GMT

Perhaps this script tool can help you get started: http://arcscripts.esri.com/details.asp?dbid=13686. Check out the link at the bottom of that page to see if there's an updated version - that site is blocked for me right now. For this script it sounds like you need to use a DEM, one that includes bathymetry. If you don't have a detailed DEM, you can still try using the the GEBCO world bathymetry dataset which has both land and water elevations, available here: http://www.gebco.net/data_and_products/gridded_bathymetry_data/ (Registration will be required). Here's the steps you need to follow:

Download the entire dataset (~ 1GB) - best resolution is 30 arc-second, and it's a zipped .nc file.

Download their Grid display software (http://www.gebco.net/data_and_products/grid_display_software/ ) and unzip it to a specified location.

Copy the .nc file to the same directory as the Grid display software

Run the software (GridViewer.exe)

Select the area or tile you want

Export it to an ESRI ASCII grid file (File -> Export Data -> Gridded data)

You may have to convert the ASCII grid file in ArcGIS and define the projection for it (WGS84?) first, I'm not sure. Also, you need to pre-define a scratch workspace (in ArcMap - Tools -> Options -> Geoprocessing -> Environments -> General Settings). Maybe this isn't required in later releases of the script tool.

At the very least you may be able to follow the logic of the included scripts to see how fetch was calculated.

Re: Fetch calculation for coastal areas

JavierLeon — Thu, 03 Jun 2010 01:19:12 GMT

Contact Dr Marji Puotinen from the School of Earth and Environmental Sciences - University of Wollongong. She has an AML and a python script to do exactly what you need.

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Fetch calculation for coastal areas

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