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#38 Singular matrix error when interpolating ground surface for output file
closed
nobody
fixed
program
critical
1.0rc3
defect
2011-05-13
2010-12-16
No
When running a batch file on 5 tiles, four of them yielded singular matrix errors when the program was interpolating the surface from the ground points for the output *.asc file. See the attached file "b61versionrc3.txt" for screen output.
Screen output showing singular matrix errors for 4 tiles
Suspect that the this error is caused by duplicate points. Tickets #34 and #35 fixed how the main classification algorithm handles duplicate points. Their solution is to set aside duplicate points so they are excluded from the classification process. Their exclusion prevents interpolation crashes during classification.
However, at the end of classification, the duplicate points are assigned the classification codes of their counterparts that went through the classification process. The ground surface is interpolated after the classification, so the duplicate points are no longer set aside, and thus, are incorrectly passed to the interpolation component.
Fixed in revision r172. The source of the error was, indeed, what was previously suspected -- duplicate ground points were causing the interpolation component to crash.
Related
Commit: [r172]