No worries!

You could also use 100% of labels for training. Of course this means that you 
cannot do the testing step.
The testing is there to evaluate the performance and quality of learned model. 
It is mostly used when developing new method, or tuning some parameters. It is 
not required if you just want the classification results. But without it, you 
will be unable to tell if it's a good one or not!

Some people even split the reference data into 3 subsets: training, validation 
and testing, for various reasons.
See this interesting page: http://stats.stackexchange.com/a/19051

There are other way to evaluate a classification model (leave-one-out, cross 
validation, etc.), but a 70/30 split into training and testing is a simple and 
common one.

Victor Poughon
________________________________
De : [email protected] [[email protected]] de la part de 
michel M [[email protected]]
Envoyé : mercredi 26 octobre 2016 14:13
À : otb-users
Objet : [otb-users] Re: exercice corrigé (training.shp et testing.shp)

Thanks victor but for me it's not again clear ...
For exemple I have a shape file  with data source corine land cover , i have a 
crop code , a label and a geometry
I put 70% of records in a testing file
and 30% of  others records in a training file
and after i don't understand the mécanism ....
why not just all records in a training shape file
many thanks


On Monday, October 24, 2016 at 5:54:38 PM UTC+2, michel M wrote:
Bonjour,
Suite au dernier corrigé de Montpellier (Theia) ,
a partir de la page 14 classification supervisée pour les séries 
multitemporelles
Je ne comprends pas la difference entre training et testing )
en effet  je suis en train de faire un petit test ( téléchargement de 9  images 
landsat sur THEIA de l'année 2014 , déja orthorectifié ... et corriger au 
niveau atmosphérique )  pour visualiser les  cultures sur une zone...
Dans les corrigés
ils ont 2 fichiers shapes training.shp et testing.shp
-- training contient la donnée d'apprentissage
-- testing contient la donnée de validation
( je comprends bien que training c'est les zones d'entraînement choisi par 
l'utilisateur )
et testing c'est quoi ??)

- si par exemple je vais  créer un fichier shape provenant des cultures de  
RPG2014 (recensement parcellaire graphique ) ,  je vais le mettre en training 
est ce OK ?
mais testing ( je ne vois pas )
Pouvez vous m'éclairer ?

merci
Michel


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