View source for Principal component analysis

= Using QGIS OTB plugin =
Does currently not work in OTB plugin for QGIS 3.4.
* In the search engine of the Processing Toolbox, type PCA and select '''DimensionalityReduction(pca)''' under Image Filtering of the Orfeo Toolbox.
* Under the Parameter tab, select Multispectral band file as the input layer.
* Select '''pca''' under the Algorithm tab.
* Enter 4 as the number of components.
* Specify the directory to save the output file.
* Untick output file after running algorithm (inverse output image) option.
* Click on {{button|text=Run}} to execute the algorithm.

= Using OTB standalone =
* Type into the search box of the Windows taskbar: {{typed|text=mapla.bat}}. Click on mapla.bat to open  Monteverdi Application Launcher.
* In the search engine of Mapla, type {{typed|text=Dimension}} and double click '''Dimensionality Reduction'''.
* Specify a multispectral image as Input Image.
* Specify directory and name for the Output image. Select the output data type {{button|text=float}} from the pull-down list.
* Select '''PCA''' from the drop-down list as Algorithm.
* Enter 4 as number of components.
* Click on {{button|text=Execute}}.

[[File:pca_otb.png|500px]][[File:pca_result.png|400px]]

[[category:QGIS Tutorial]]