what's wrong with the seagrid spacer?

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leon
Posts: 78
Joined: Mon Mar 03, 2008 4:14 am

what's wrong with the seagrid spacer?

#1 Post by leon » Mon Jun 22, 2009 3:02 am

It is said that seagrid can change the space of the grid by change the position of the spacer. I did as the seagrid tutorial, but the spacing is not changing. What's wrong with the seagrid spcaer? Can someone tell me why it doesn't work for me? Thank you very much~

leon
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rsignell
Posts: 123
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Re: what's wrong with the seagrid spacer?

#2 Post by rsignell » Tue Jun 23, 2009 4:20 pm

Leon,

I just tried it, and it works for me. You are supposed to click-and-drag to move the spacers closer or further apart. I had to keep clicking on <toggle>=>refresh to keep the spacers visible, but other than that, it worked okay, and I used it to focus grids toward the center of a test grid as below:

Image

BTW, I just built a new version of the Seagrid Mex files for 2009a. They finally got serious about their threat to take away "finite", and also the mex file code needed all lines with "mxCreateFull" changed to "mxCreateDoubleMatrix". Seagrid is available on our SVN at:

Code: Select all

svn co http://svn1.hosted-projects.com/cmgsoft/m_cmg/trunk/seagrid  seagrid
and the new mex files are in the "mex_matlab78_win32" subdirectory.

-Rich

leon
Posts: 78
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Re: what's wrong with the seagrid spacer?

#3 Post by leon » Wed Jun 24, 2009 3:25 am

Thank you very much, rich. I know what's the problem. The seagrid that I use is from the RNT toolbox. Maybe it's different or old, so the spacer is not working. I download the one you told me. And the spacer works well. The RNT users should remeber that the RNT seagrid is to some extent different from the latest version. Thank you again,rich.

leon

hugobastos
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Re: what's wrong with the seagrid spacer?

#4 Post by hugobastos » Wed Jun 24, 2009 2:06 pm

I see this problem a long time ago, but i think u must try to disable the the mex checkbox .

:arrow: Open Seagrid, Select menu View, and uncheck the Mex box on the end of the window!

Check if works!

rsignell
Posts: 123
Joined: Fri Apr 25, 2003 9:22 pm
Location: USGS

Re: what's wrong with the seagrid spacer?

#5 Post by rsignell » Thu Jun 25, 2009 2:24 am

I do NOT recommend avoiding the mex files with SeaGrid. Chuck Denham, the author of this tool, tried to make non-mex versions of the elliptic solver and the other mex files, but it didn't work out so well. If you don't use the mex files, you will get a grid, but it may be wildly nonorthogonal.

leon
Posts: 78
Joined: Mon Mar 03, 2008 4:14 am

Re: what's wrong with the seagrid spacer?

#6 Post by leon » Thu Jun 25, 2009 3:13 am

Actually, when I use the seagrid in RNT toolbox to compute the land mask, it always costs such a long time. Why does it cost such a long time? I know it depends on the number of grids and the computing domain. Are there other reasons? Which process costs the longest time? Can we improve it ?

rsignell
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Location: USGS

Re: what's wrong with the seagrid spacer?

#7 Post by rsignell » Thu Jun 25, 2009 11:58 am

Is it really the land masking that is taking a long time, or the bathymetry gridding?

Seagrid uses a rather slow inverse distance algorithm for bathymetry interpolation, so if you have a large number of bathymetry points, it takes a long time.

There is really no need to do bathymetry gridding in Seagrid: there is an argument that it really should be done by a separate program as a 2nd step. Yet it's nice to see some representation of the bathymetry when you are fiddling with the grid. So I often subsample the bathymetry points so that gridding in Seagrid is quick, then after the file is saved, redo the bathymetry interpolation outside of Seagrid using the full set of bathymetric points or another method (interp2 from a high res DEM, etc.)

leon
Posts: 78
Joined: Mon Mar 03, 2008 4:14 am

Re: what's wrong with the seagrid spacer?

#8 Post by leon » Thu Jun 25, 2009 2:05 pm

Yes,it's the land mask computing which cousts a long time. But the seagrid I use is from the RNT toolbox( http://eros.eas.gatech.edu/RNT/ ). Maybe there are some different. I usually load the coastline first, then setup the grids and computing land mask. Finally, adding bathyment and editing land mask.

leon

hugobastos
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Re: what's wrong with the seagrid spacer?

#9 Post by hugobastos » Thu Jun 25, 2009 3:10 pm

rsignell wrote:I do NOT recommend avoiding the mex files with SeaGrid. Chuck Denham, the author of this tool, tried to make non-mex versions of the elliptic solver and the other mex files, but it didn't work out so well. If you don't use the mex files, you will get a grid, but it may be wildly nonorthogonal.
Nice to know. Thankz!

nacholibre
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Re: what's wrong with the seagrid spacer?

#10 Post by nacholibre » Thu Jul 09, 2009 9:37 pm

rsignell wrote:I do NOT recommend avoiding the mex files with SeaGrid. Chuck Denham, the author of this tool, tried to make non-mex versions of the elliptic solver and the other mex files, but it didn't work out so well. If you don't use the mex files, you will get a grid, but it may be wildly nonorthogonal.
You may find an exaggerated example of a grid generated with/without mex files. It is most likely that the grid generated without the mex files will be geographically incorrect in the end.
Attachments
without mex
without mex
with mex
with mex

stevekwan
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Location: hydraulic modeling concepts

Re: what's wrong with the seagrid spacer?

#11 Post by stevekwan » Fri Mar 19, 2010 9:29 pm

is it possible to get spacers to appear on all 4 sides? whenever i make change the spaces from sides 1 and 3 to 2 and 4, my grid gets all skewed. is there any way to stabilize the grid spacings before I change sides?

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kate
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Joined: Wed Jul 02, 2003 5:29 pm
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Re: what's wrong with the seagrid spacer?

#12 Post by kate » Sat Mar 20, 2010 12:50 am

This method doesn't let you have spacers on all four sides.

stone

Re: what's wrong with the seagrid spacer?

#13 Post by stone » Mon Nov 08, 2010 2:11 pm

Hi,
I download seagrid from http://svn1.hosted-projects.com/cmgsoft ... nk/seagrid
When I use spacing ,It does the spacing work,But Matlab always crash immediately with a error "terminate called after throwing an instance of 'Mathworks::System::SimpleException' "
My OS is Ubuntu i686 with Matlab 2008a
Mathworks support on http://www.mathworks.com/support/soluti ... n=1-36MHWQ does not work either.
What is wrong there?

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