Stat I/O Routines

The statistics service routines can be called by an application program to manipulate data within a statistics file.

Statistics I/O utilizes a three-level tree structure. The three levels are:

Level 0 - Items associated with an entire image, e.g., eigenvectors, eigenvalues and the number of bands in the image.
Level 1 - Items associated with classes, e.g., number of training sites, class mean vector, covariance matrix and class name.
Level 2 - Items associated with training sites, e.g., vertices of the polygon defining the site, histogram of intensities within the polygon and site name.

Each statistical data item is made up of the following:

data_type -     The name of the data item.  This is a character string 
                of 26 characters including a null character at the end.
                Some examples are: "NAME," "HIST001," "COVARIANCE_MATRIX,"
                "POLYGON."  Two data_types are reserved by Stat I/O:
                "CLASSLIST" and "SITELIST."  

                Valid items for each level of a statistics file are:     

                                     Image   Class   Site
                NBANDS                 X
                NCLASSES               X
                CONFUSION_MATRIX       X
                MEAN_VECTOR            X       X       X
                COVARIANCE_MATRIX      X       X       X 
                CORRELATION_MATRIX     X       X       X
                HISTOGRAMS             X       X       X
                EIGENVALUES            X       X       X
                EIGENVECTORS           X       X       X
                NPOINTS                        X       X
                NSITES                         X
                BOUNDS                         X
                PROBABILITY                    X
                NAME                           X       X
                NVERTICES                              X 
                POLYGON                                X
                HORIZONTAL_MARK                        X 


shape -         A nine element integer array which describes the data
                in the record.  The first element specifies the data
                type.  The second element is the number of indices
                (dimensions) associated with the data.  For example,
                if the data is a matrix, then specify 2.  The range for
                this element is 1 through 7.  The remaining seven 
                elements are the ranges of the indices.  Permissible
                values are: 

                    = EBYTE:       byte data
                    = EWORD:       16-bit integer
                    = ELONG:       32-bit integer
                    = EREAL:       single-precision floating point number
                    = EDOUBLE:     double-precision floating point number
                    = ECOMP:       single-precision complex number
                    = EDCOMP:      double-precision complex number

data -          The actual statistical data.

An application program can access these routines by linking in the following object library:

     $LASLIB/las.a

This is a list of available Stat I/O Routines: