[Qgis-user] Principal Components Analysis Problem

[Nyall Dawson]

On 11 April 2018 at 16:57, Grant Boxer <boxerg at iinet.net.au> wrote:
> I am trying to do a PCA on ASTER satellite data using bands 4 through 9 (all
> 30 m pixel size). I have tried using the Processing Toolbox > Grass >
> Imagery>i.pca but it continually fails.
>
>
>
> I get this at the end of processing.
>
> _____________________________________________________________________________________________________________
>
> Traceback (most recent call last):
> File
> "C:/PROGRA~1/QGIS3~1.0/apps/qgis/./python/plugins\processing\algs\grass7\Grass7Algorithm.py",
> line 395, in processAlgorithm
> if isinstance(out, QgsProcessingOutputHtml):
> NameError: name 'QgsProcessingOutputHtml' is not defined

Unfortunately this is a known bug in 3.0.1, fixed in the upcoming
3.0.2 version (along with a TON of other Processing GRASS plugin
fixes).

As a short-term fix you could try downloading the qgis-rel-dev package
via osgeo4w64 to get access to these fixes before the official release
of 3.0.2.

Nyall


>
> Execution failed after 16.32 seconds
>
>
>
> Loading resulting layers
>
> Algorithm 'i.pca - Principal components analysis (PCA) for image
> processing.' finished
>
> _____________________________________________________________________________________________________________
>
> When using the SemiAutomatic Classification PCA calculator I get the
> following error message.
>
>
>
> 2018-04-11T14:51:00 WARNING Traceback (most recent call last):
>
> File
> "C:/Users/Grant/AppData/Roaming/QGIS/QGIS3\profiles\default/python/plugins\SemiAutomaticClassificationPlugin\maininterface\pcaTab.py",
> line 46, in calculatePCAAction
>
> self.calculatePCA()
>
> File
> "C:/Users/Grant/AppData/Roaming/QGIS/QGIS3\profiles\default/python/plugins\SemiAutomaticClassificationPlugin\maininterface\pcaTab.py",
> line 97, in calculatePCA
>
> self.PCACalculation(rD, bL, outF, numbComp, None, batch)
>
> File
> "C:/Users/Grant/AppData/Roaming/QGIS/QGIS3\profiles\default/python/plugins\SemiAutomaticClassificationPlugin\maininterface\pcaTab.py",
> line 140, in PCACalculation
>
> comp, totalVariance, totalVarianceCumulative, eigenValues =
> self.calculateEigenVectors(covM)
>
> File
> "C:/Users/Grant/AppData/Roaming/QGIS/QGIS3\profiles\default/python/plugins\SemiAutomaticClassificationPlugin\maininterface\pcaTab.py",
> line 264, in calculateEigenVectors
>
> val, vect = cfg.np.linalg.eigh(matrix)
>
> File
> "C:\PROGRA~1\QGIS3~1.0\apps\Python36\lib\site-packages\numpy\linalg\linalg.py",
> line 1291, in eigh
>
> w, vt = gufunc(a, signature=signature, extobj=extobj)
>
> File
> "C:\PROGRA~1\QGIS3~1.0\apps\Python36\lib\site-packages\numpy\linalg\linalg.py",
> line 96, in _raise_linalgerror_eigenvalues_nonconvergence
>
> raise LinAlgError("Eigenvalues did not converge")
>
> numpy.linalg.linalg.LinAlgError: Eigenvalues did not converge
>
> _____________________________________________________________________________________________________________
>
> Can anyone shed any light on what is happening here?
>
>
>
> Cheers Grant
>
>
>
> Grant Boxer (FAIG RPGeo)
>
> Maylands, Western Australia, 6931
>
>
>
>
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