Revision as of 13:56, 4 July 2019

Per pixel classification with QGIS and OTB processing plugin

In the search engine of Processing Toolbox, type TrainImages and open TrainImagesClassifer.
In the Input Image List select a (or optional: several) multispectral images: Subset_S2A_MSIL2A_20170619T_MUL.tif .
In the Validation Vector Data List and choose a vector polygon file with an independent sample of validation areas: lucc_validation.shp.
Type C_ID in the {button|text=Field Name}} text field.
Choose Support Vector Machine Classifer libsvm from the drop down list.
SVM Model Type is csvc
The SVM Kernel Type is Linear.
Switch checkbox Parameters optimization on.
In the Output model specify an model file: e.g. lucc_svm.model
Define an output file for Output confusion matrix or contingency table (e.g.lucc_svm_confusion.csv).
Click Run.
Click on the Log tab and inspect the quality measures: Precision, Recall, F-score and Kappa index.

In the search engine of Processing Toolbox, type ImageClassifier and double click ImageClassifier.
Set Subset_S2A_MSIL2A_20170619T_MUL.tif as Input image.
Set Input _mask to blank (top of drop-down list).
Set lucc_svm.model as Model file.
Set Output pixel type to uint8
Save the Output image as svm_classification.tif.
Uncheck Confidence map: Open output file after running algorithm.
Add svm_classification.tif to QGIS canvas.
Download the style file classifcation.qml from Stud.IP.
Right click svm_classification.tif in the TOC and select Properties --> Style --> Style --> Load Style.
Select the style file \lucc\classification.qml. OK.
Open the text file lucc_svm_confusion.csv with LibrOffice Calc or MS Excel and calculate overall, user, producer accuracy and kappa index.

Type into the search box of the Windows taskbar: mapla.bat. Click on mapla.bat to open Monteverdi Application Launcher.
In the search engine of mapla, type TrainImages and double click TrainImagesClassifer.
In the Input Image List click on + and select a (or optional: several) multispectral images: Subset_S2A_MSIL2A_20170619T_MUL.tif .
In the Input Vector Data List choose a vector polygon file with training areas: lucc_training_input.shp.
Activate the checkbox Validation Vector Data List and choose a vector polygon file with an independent sample of validation areas: lucc_validation.shp
In the Output model specify an output model file: e.g. lucc_svm.model
Activate the checkbox and save the Output confusion matrix or contingency table as lucc_svm_confusion.csv.
In the Bound sample number by minimum field type 1.
Set the training and validation sample ratio to 0. (0 = all training data).
Mark C_ID in the Field containing the class integer label (C_ID refers to the column that contains the LUC code in the training and validation vector file).
Choose LibSVM classifier from the drop down list as Classifier to use for the training.
The SVM Kernel Type is Linear.
The SVM Model Type is C support vector classification.
Switch the Parameters optimization to on.
Check user defined seed and enter an integer value.
Click on Execute.
Click on the Log tab and inspect the quality measures: Precision, Recall, F-score and Kappa index.

In the search engine of mapla, type ImageClassifier and double click ImageClassifier
Set Subset_S2A_MSIL2A_20170619T_MUL.tif as Input image.
Set SVM.model as Model file.
Save the Output image as svm_classification.tif.

Evaluate classification results:
Add svm_classification.tif to QGIS canvas.
Download the style file classifcation.qml from Stud.IP.
Right click svm_classification.tif in the TOC and select Properties --> Style --> Style --> Load Style.
Select the style file \lucc\classification.qml. OK.
Open the text file lucc_svm_confusion.csv with LibrOffice Calc or MS Excel and calculate overall, user, producer accuracy and kappa index.

@@ Line 27: / Line 27: @@
 * Right click ''svm_classification.tif'' in the [[TOC]] and select {{mitem|text=Properties --> Style --> Style --> Load Style}}.
 * Select the style file '''\lucc\classification.qml'''. {{button|text=OK}}.
 * Open the text file '''lucc_svm_confusion.csv''' with LibrOffice Calc or MS Excel and calculate overall, user, producer accuracy and kappa index.
+[[File:qgis_otb_imageclassifier.png|400px]]
 =Per pixel classification with OTB standalone=