Joined: Fri Sep 11, 2009 1:48 pm Posts: 61 Location: nmefc

when i creat the grid file by EASYGRID, it report a error! In the easygrid.m files, I set % Geographical and Grid parameters  lat = 0.86; % Latitude (degrees) of the bottomleft corner of the grid. lon = 99; % Longitude (degrees) of the bottomleft corner of the grid. X = 3120000; % Width of domain (meters) 26.33 Y = 2800000; % Length of domain (meters) rotangle = 0; % Angle (degrees) to rotate the grid conterclockwise resol = 11000; % Cell width and height (i.e. Resolution)in meters. Grid cells are forced to be (almost) square. N = 10; % Number of vertical levelsAnd the *_bathy.mat file is created by myself, and the area is 0.8~26.5N 98.5~131 E,resolution is 2 minutes. ??? Error using ==> qhullmx qhull precision warning: The initial hull is narrow (cosine of min. angle is 1.0000000000000002). A coplanar point may lead to a wide facet. Options 'QbB' (scale to unit box) or 'Qbb' (scale last coordinate) may remove this warning. Use 'Pp' to skip this warning. See 'Limitations' in http://www.qhull.org/html/qhimpre.htm
qhull precision error: initial simplex is not convex. Distance=1.2e014
While executing:  qhull d Qt Qbb Qc
Options selected for Qhull 2003.1 2003/12/30: delaunay Qtriangulate Qbboundlast Qcoplanarkeep _premerge _zerocentrum Pgood Qinteriorkeep _maxwidth 35 Errorroundoff 1.6e013 _onemerge 1.2e012 Visibledistance 3.3e013 Ucoplanardistance 3.3e013 Widthoutside 6.6e013 _widefacet 2e012 _narrowhull 2.2e016
precision problems (corrected unless 'Q0' or an error)
1 flipped facets
The input to qhull appears to be less than 3 dimensional, or a computation has overflowed.
Qhull could not construct a clearly convex simplex from points:
The center point is coplanar with a facet, or a vertex is coplanar with a neighboring facet. The maximum round off error for computing distances is 1.6e013. The center point, facets and distances to the center point are as follows:
facet p160696 p378 p0 distance= 8.9e015
facet p161074 p378 p0 distance= 1.8e015
facet p161074 p160696 p0 distance= 1.8e015
facet p161074 p160696 p378 distance= 3.6e015
These points either have a maximum or minimum xcoordinate, or they maximize the determinant for k coordinates. Trial points are first selected from points that maximize a coordinate.
The min and max coordinates for each dimension are:
0: 99 130.5 difference= 31.5
1: 0.8333 36.17 difference= 35.33
2: 0 35.33 difference= 35.33
If the input should be full dimensional, you have several options that may determine an initial simplex:  use 'QJ' to joggle the input and make it full dimensional  use 'QbB' to scale the points to the unit cube  use 'QR0' to randomly rotate the input for different maximum points  use 'Qs' to search all points for the initial simplex  use 'En' to specify a maximum roundoff error less than 1.6e013.  trace execution with 'T3' to see the determinant for each point.
If the input is lower dimensional:  use 'QJ' to joggle the input and make it full dimensional  use 'Qbk:0Bk:0' to delete coordinate k from the input. You should pick the coordinate with the least range. The hull will have the correct topology.  determine the flat containing the points, rotate the points into a coordinate plane, and delete the other coordinates.  add one or more points to make the input full dimensional.
This is a Delaunay triangulation and the input is cocircular or cospherical:  use 'Qz' to add a point "at infinity" (i.e., above the paraboloid)  or use 'QJ' to joggle the input and avoid cocircular data
Error in ==> delaunayn at 117 t = qhullmx(x', 'd ', opt);
Error in ==> griddata>linear at 151 tri = delaunayn([x y]);
Error in ==> griddata at 120 zi = linear(x,y,z,xi,yi,opt);
Error in ==> south_sea_easygrid at 281 h = griddata(xbathy,ybathy,zbathy,lon_rho,lat_rho,'linear');But when I run easygrid.m and use the depth from ETOPO5 by [xbathy,ybathy,zbathy]=read_srtm30plus(lon_range+1,lat_range,300); %This reads in worldwide bathymetry at 60 second (1 minute) resolution, %30seconds max [xbathy,ybathy]=meshgrid(xbathy,ybathy); xbathy = xbathy(:); %columnize ybathy = ybathy(:); %columnize zbathy = zbathy(:); %columnize, and make depth positive % outname=strcat(name,'_bathy.mat','interpreter','none') save([name,'_bathy.mat'],'xbathy','ybathy','zbathy')it is OK. So I don't know the reasons when I use my depth mat file, it is created by dat=load('55.dat'); zbathy=dat(:,3); ybathy=dat(:,1); xbathy=dat(:,2); save south_sea_bathy xbathy ybathy zbathyWho can tell me the reasons for that? Thank you very much!!

