Hello,
I looked at this problem and the exception comes from a bug in TrainImagesClassifier. I made a fix that will be included in otb 7.1.0.
Oddly, the exception is caused by the presence of a OFTReal field in the in input vector data (the SURF field). This field is ignored in the first steps of the application but not in the learning step, where it is one of the field that can be used for classification. As a result the field list is messed up and the application tries to use the Nom_nomenc field for the learning, resulting in the conversion error.
OTB 7.1.0 will be available soon, in the meantime you can :
- Use
TrainVectorClassifierinstead ofTrainImagesClassifier, but you will to perform the sampling operations by yourself (PolygonClassStatistics,SampleSelectionandSampleExtraction, see the learning recipe - Alternatively, remove the
SURFfield before usingTrainImagesClassifier.
Cédric