[Octave-bug-tracker] [bug #61961] Griddata cannot produce mesh on vertical vertices

[Razdvizh]

URL:
  <https://savannah.gnu.org/bugs/?61961>

                 Summary: Griddata cannot produce mesh on vertical vertices
                 Project: GNU Octave
            Submitted by: razdvizh
            Submitted on: Sat 29 Jan 2022 09:27:54 AM UTC
                Category: Octave Function
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: None
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
                 Release: 5.2.0
         Discussion Lock: Any
        Operating System: Any

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Details:

With some slope you could get decent result, but if slope became little or
none you've got blanks

Example is for cylinder. 
See also https://octave.discourse.group/t/strange-result-with-griddata/2147

clear all;clf
f2=fopen("c5.bin","rb+");coord=fread(f2,[47716,3],"double");fclose(f2);
f2=fopen("c6.bin","rb+");coordnum=fread(f2,[152,1],"double");fclose(f2);

limits = [min([coord(:,1)]), max([coord(:,1)]) ,...
min([coord(:,2)]), max([coord(:,2)]),...
min([coord(:,3)]), max([coord(:,3)])];
xlabel("x");ylabel("y");zlabel("z");

invs=@(n) line("xdata",coord(1+coordnum(n):coordnum(n+1),1), ...
"ydata",coord(1+coordnum(n):coordnum(n+1),2), ...
"zdata",coord(1+coordnum(n):coordnum(n+1),3),"color", "b", "marker", "none");

axis ("equal",limits);
view(3);
xlabel("x");ylabel("y");zlabel("z");

g_step=20;
Nr=1:g_step:rows(coordnum);
hl1=arrayfun(invs, Nr);
hold on;
 
 [xx,yy] = meshgrid (linspace (min(coord(:,1)),max(coord(:,1)),200));
  zz = griddata (coord(:,1),coord(:,2),coord(:,3),xx,yy);
 mesh(xx,yy,zz);
 hidden('off');



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File Attachments:


-------------------------------------------------------
Date: Sat 29 Jan 2022 09:27:54 AM UTC  Name: s6.png  Size: 51KiB   By:
razdvizh

<http://savannah.gnu.org/bugs/download.php?file_id=52772>
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Date: Sat 29 Jan 2022 09:27:54 AM UTC  Name: c6.bin  Size: 1KiB   By: razdvizh

<http://savannah.gnu.org/bugs/download.php?file_id=52773>
-------------------------------------------------------
Date: Sat 29 Jan 2022 09:27:54 AM UTC  Name: c5.bin  Size: 1MiB   By: razdvizh

<http://savannah.gnu.org/bugs/download.php?file_id=52774>

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  <https://savannah.gnu.org/bugs/?61961>

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