grid error

[ykcho]

I'am using seagrid with Matlab 7 in windows envirnoment with mexnc and NetCDF_Toolbox.

matlba error massege

??? warning - tracking error

Error in ==> mexrect2grid at 98
zrect = feval('mexrect', zrect, length(zrect), ...

Error in ==> seagrid.gridcalc at 179
[w, err] = feval(theFcn, zti, [], ci, [m n]); % <Error> seagrid.dogrid at 64
gridcalc(self) % <Calculate> seagrid.doupdate at 92
dogrid(self, needsUpdate); % <== Step #2 <Error> seagrid.doevent at 188
doupdate(self)

Error in ==> psevent at 25
doevent(ps(gcbf), theEvent, theMessage);

??? Error while evaluating uimenu Callback.

can sombody help me to fix this...?

[wilkin]

Did you type "tracking error" in the ROMS Forum search? There are a number of postings related to this subject.

I repeat previous comments here:

The "tracking error" is a failure of the conformal mapping algorithm to map the irregular boundary to a rectangle. It is deep inside the Ives and Zacharias algorithm that underpins seagrid and other related grid generating tools.

It is true that this error does tend to occur more frequently if the boundary has a large number of points, but is also more likely to be triggered in grids with high aspect ratios or highly variable distributons of points along a long boundary. Are these features of your grid?

Do you get an acceptable looking grid with smaller numbers of boundary points?

Is the tracking error sensitive to the number of points along one particular boundary, more than the other?

If the boundary you specify is quite irregular, check whether you end up with some very small or very large cells. If you have an unacceptably large range of cell sizes (that will cause strict CFL time step limitations later) then consider smoothing out the input boundary curve a little. This generally reduces the demands on the conformal mapping step.

If you still have problems, include a small gif/jpeg of your boundary shape in your next post.

John.