| selcld | Select classes according to a boolean expression |
| -c <cldata> | source classified data frame |
| -cout <trgcldata> | target classified data |
| -expr <expr>; | expression to be evaluated |
| [-v] | verbose evaluation |
| [-empty] | create also empty classes |
This operation selects classes from a source classified data to a target classified data. Because the names in the expression refer to a data frame, the source classified data has to correspond to this data frame. In other words, there must be a class in the source classified data for each data record referred to from the expression.
The flag -empty defines, that empty classes should be created for each class in the source classified data anyway. The other alternative is to pick only those classes that match the expression. More information about expressions can be found in section 4.3.1.
Example (ex4.6): Because TS-SOM has several layers, it is often necessary to pick only one of them. For instance, it is more sensible to use only one selected layer as a classifier. The following commands perform that:
# Perform typical sequence for training a SOM (som), # for creating a SOM classification (cld), # and so forth ... # Evaluate SOM layer indexes into a field NDA> somlayer -s som -fout somlay # Select classes from the 3rd layer NDA> selcld -c cld -cout cld3 -expr 'somlay' = 3; -empty