Supervised classification (Tutorial)

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(Training of per-pixel classifier)
(Training of per-pixel classifiers)
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* Type into the search box of the Windows taskbar: {{typed|text=mapla.bat}}. Click on mapla.bat to open  Monteverdi Application Launcher.
 
* 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=TrainImages}} and double click '''TrainImagesClassifer'''.
 
* In the search engine of mapla, type {{typed|text=TrainImages}} and double click '''TrainImagesClassifer'''.
* In the {{button|text=Input Image List}} click on {{button|text=+}} and select one (optional: several) multispectral images: '''Subset_S2A_MSIL2A_20170619T_MUL.tif '''.
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* In the {{button|text=Input Image List}} click on {{button|text=+}} and select a (or optional: several) multispectral images: '''Subset_S2A_MSIL2A_20170619T_MUL.tif '''.
 
* In the {{button|text=Input Vector Data List}} choose a vector polygon file with training areas: '''lab07_training_input.shp'''.
 
* In the {{button|text=Input Vector Data List}} choose a vector polygon file with training areas: '''lab07_training_input.shp'''.
 
* Activate the checkbox {{button|text=Validation Vector Data List}} and choose a vector polygon file with an independent sample of validation areas: '''lab07_validation_input.shp'''
 
* Activate the checkbox {{button|text=Validation Vector Data List}} and choose a vector polygon file with an independent sample of validation areas: '''lab07_validation_input.shp'''
* Set ''Subset_S2A_MSIL2A_20170619T_MUL_BOA.tif.xml'' as {{button|text=Input XML image statistics file}}.
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* In the {{button|text=Output model}} specify an output model file: e.g. '''svm.model'''
* Set {{button|text=Name of discrimination field}} to ''C_ID'' (C_ID refers to the column that contains the LUC code).
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* Activate the checkbox and save the {{button|text=Output confusion matrix or contingency table}} as '''ConfusionMatrixSVM.csv'''.
* Save the {{button|text=Output confusion matrix}} as ''ConfusionMatrixSVM.csv''.
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* In the {{button|text=Bound sample number by minimum}} field type {{typed|text=0}}.
* Save the {{button|text=Output model}} as ''SVM.model''.
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* Set the {{button|text=training and validation sample ratio}} to {{typed|text=0 }}. (0 = all training data).
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* Set {{button|text=Field containing the class integer label}} to ''C_ID'' (C_ID refers to the column that contains the LUC code in the training and validation vector file).
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* Choose {{button|text=LibSVM classifier}} from the drop down list as Classifier to use for the training.
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* The SVN Kernel Type is {{button|text=Gaussian radial basis function}}.
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* Switch the Parameters optimization to {{button|text=on}}.
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* Set user defined seed with an integer value.
 
* Click on {{button|text=Execute}}.
 
* Click on {{button|text=Execute}}.
* Calculation of accuracies :<br/> Open ''ConfusionMatrixSVM.csv'' in LibreOffice or MS Excel and calculate overall, producer and consumer accuracies.
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[[File:qgis_trainImagesClassifier_svm.png|500px]]
  
 
== Classification==
 
== Classification==

Revision as of 18:18, 8 December 2018

Contents

Classification with Orfeo Toolbox

Training of per-pixel classifiers

  • 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: lab07_training_input.shp.
  • Activate the checkbox Validation Vector Data List and choose a vector polygon file with an independent sample of validation areas: lab07_validation_input.shp
  • In the Output model specify an output model file: e.g. svm.model
  • Activate the checkbox and save the Output confusion matrix or contingency table as ConfusionMatrixSVM.csv.
  • In the Bound sample number by minimum field type 0.
  • Set the training and validation sample ratio to 0. (0 = all training data).
  • Set Field containing the class integer label to C_ID (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 SVN Kernel Type is Gaussian radial basis function.
  • Switch the Parameters optimization to on.
  • Set user defined seed with an integer value.
  • Click on Execute.

500px

Classification

  1. Open Orfeo Toolbox --> Image Classification (see figure C).
  2. Set Subset_S2A_MSIL2A_20170619T_MUL_BOA.tif as Input image.
  3. Set SVM.model as Model file.
  4. Set Subset_S2A_MSIL2A_20170619T_MUL_BOA.xml as Statistical file.
  5. Save the Output image as su_svm.tif.
  6. Evaluate classification results.
    1. Add the classification result su_svm.tif to QGIS.
    2. Right click su_svm.tif in the TOC and select Properties --> Style --> Style --> Load Style.
    3. Load lab05_MinDist.qml.

Compute a confusion matrix with independent reference data

  1. Open Orfeo Toolbox --> ComputeConfusionMatrix (Vector).
  2. Set su_svm.tif as Input image.
  3. Set lab05_validation.shp as Input reference vector data.
  4. Set Field name to C_ID.
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