Which software is better to make a curve orthogonal grid?

General scientific issues regarding ROMS

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zym1989
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Which software is better to make a curve orthogonal grid?

#1 Post by zym1989 » Wed May 21, 2014 9:12 am

QQ图片20140520234352.jpg
I am looking for a software which can make a curve orthogonal grid and it can adjust every grid cell .I mean that the software has high freedom to change every grid cell and focus point. Don't laugh at me.I'm new. I was using seagrid ,but it has many limit condition so the grid drawn by seagrid can't fit my requirements. How can I draw a grid like the picture by seagrid?

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kate
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Re: Which software is better to make a curve orthogonal grid

#2 Post by kate » Wed May 21, 2014 4:18 pm

I don't have any way to make that exact grid. Both Seagrid and my Fortran code are based on a routine called "rect" which requires your domain to map to a rectangle. Our Python tools instead use a routine called "gridgen" which can have a more complex boundary. However, I don't know how to get gridgen to make curved edges between the boundary points.

The model delft3d has a more capable grid generation tool which appears to be called RGF-grid. Lyon Lanerolle has had good luck with using it to make ROMS grids. I'm not sure what the licensing and costs are on it.

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wilkin
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Re: Which software is better to make a curve orthogonal grid

#3 Post by wilkin » Thu May 22, 2014 12:49 am

That's an intriguing grid with some obvious attractive features with respect to enhanced resolution in coastal Vietnam. If you have the numeric grid coordinates you can build the grid file directly by computing the lon/lat of u,v and rho points, and the grid metrics pm, pn, and construct a land/sea mask with other tools we have available.
John Wilkin: DMCS Rutgers University
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d.kobashi
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Re: Which software is better to make a curve orthogonal grid

#4 Post by d.kobashi » Thu May 22, 2014 4:09 am

If you are after a GUI tool easy to use and if you use Windows, Delft3D RGFGRID may be your best option so far. You can create detailed curvilinear grids using the tool.

Now you can even save grids as ROMS netcdf grid file with RGFGRID. But you will need to tweak a bit after you create a ROMS grid file (I had to do that a while ago for a older version of RGFGRID). You can get RGFGRID for free of charge until Deltares releases its source code (not sure when).
You can request the tool from the following site.
http://oss.deltares.nl/web/delft3d/sour ... 41089452C6
There is a Linux version as well, but it was not stable when I tried it; whereas, RGFGRID for Windows was (and probably still is) stable.

Also, there is a tool called pygridgen and according to the web site, it comes with GUI. I have never used it, though. You might want to check it out.
https://github.com/hetland/pygridgen

Hope this helps.

DJ

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kate
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Re: Which software is better to make a curve orthogonal grid

#5 Post by kate » Thu May 22, 2014 4:27 pm

Once you manage to create this grid, you should know that ROMS will want you to run it as multiple grid patches, as in the dogbone example. Otherwise, you would not be able to apply open boundary conditions where they should be applied. To run as one ROMS grid, you would have to create a much larger rectangular grid and mask out the portions that are not shown. ROMS would then see the boundaries as being internal to that larger grid, with solid walls on the boundaries.

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